AAA Working Group Pat R. Calhoun Internet-Draft Black Storm Networks Category: Standards Track William Bulley <draft-ietf-aaa-diameter-nasreq-09.txt> Merit Network, Inc. | Allan C. Rubens Tut Systems, Inc. Jeff Haag Glen Zorn Cisco Systems, Inc. David Spence | Interlink Networks, Inc. | March 2002 | Diameter NASREQ Application Status of this Memo This document is an Internet-Draft and is subject to all provisions | of Section 10 of RFC2026. | Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at: http://www.ietf.org/1id-abstracts.html | The list of Internet-Draft Shadow Directories can be accessed at: http://www.ietf.org/shadow.html. This memo describes work in progress within the AAA Working Group. | Comments are welcome and should be submitted to aaa-wg@merit.edu. Distribution of this memo is unlimited. Copyright (C) The Internet Society 2002. All Rights Reserved. | Calhoun et al. expires September 2002 [Page 1]
Internet-Draft Diameter NASREQ Application March 2002 Abstract This document describes the Diameter application that is used for AAA in a PPP/SLIP Dial-Up and Terminal Server Access environment. This application, combined with the base protocol, satisfies the requirements defined in the NASREQ AAA criteria specification and the ROAMOPS AAA Criteria specification. Given that it is expected that initial deployments of the Diameter protocol in a dial-up environment will include legacy systems, this application was carefully designed to ease the burden of servers that must perform protocol conversion between RADIUS and Diameter. This is achieved by re-using the RADIUS address space, eliminating the need to perform attribute lookups. Table of Contents 1.0 Introduction 1.1 Requirements language 1.2 Advertising application support 2.0 Supported AVPs 2.1 Diameter AVPs 2.1.1 NAS-Filter-Rule AVP 2.1.2 NAS-Session-Key AVP 2.1.3 NAS-Key-Direction AVP 2.1.4 NAS-Key-Type AVP 2.1.5 NAS-Key-Data AVP 2.1.6 NAS-Key-Binding AVP 2.1.7 NAS-Key-Lifetime AVP 2.1.8 NAS-IV AVP 2.2 Legacy RADIUS Attributes 2.2.1 NAS-IP-Address AVP 2.2.2 NAS-Identifier AVP 2.2.3 State AVP 3.0 Legacy RADIUS Authentication Support 3.1 Command-Codes Values 3.1.1 AA-Request (AAR) Command 3.1.1.1 User-Password AVP 3.1.1.2 CHAP-Auth AVP 3.1.1.3 CHAP-Ident AVP 3.1.1.4 CHAP-Algorithm AVP 3.1.1.5 CHAP-Response AVP 3.1.1.6 CHAP-Challenge AVP 3.1.1.7 ARAP-Password AVP 3.1.2 AA-Answer (AAA) Command 3.1.2.1 ARAP-Challenge-Response AVP 3.1.2.2 Password-Retry AVP Calhoun et al. expires September 2002 [Page 2]
Internet-Draft Diameter NASREQ Application March 2002 3.1.2.3 Prompt AVP 3.2 Reply-Message AVP 4.0 Extensible Authentication Protocol Support 4.1 Alternative Uses 4.2 Command-Codes Values 4.2.1 Diameter-EAP-Request (DER) Command 4.2.2 Diameter-EAP-Answer (DEA) Command 4.3 EAP-Payload AVP 5.0 Diameter Session Termination 6.0 Call and Session Information 6.1 NAS-Port AVP 6.2 Filter-Id AVP 6.3 Callback-Number AVP 6.4 Callback-Id AVP 6.5 Idle-Timeout AVP 6.6 Called-Station-Id AVP 6.7 Calling-Station-Id AVP 6.8 NAS-Port-Type AVP 6.9 Port-Limit AVP 6.10 Connect-Info AVP 7.0 Service Specific Authorization AVPs 7.1 Service-Type AVP 7.2 Framed Access Authorization AVPs 7.2.1 Framed-Protocol AVP 7.2.2 Framed-Routing AVP 7.2.3 Framed-MTU AVP 7.2.4 Framed-Compression AVP 7.2.5 IP Access 7.2.5.1 Framed-IP-Address AVP 7.2.5.2 Framed-IP-Netmask AVP 7.2.5.3 Framed-IP-Route AVP 7.2.5.4 Framed-Interface-Id AVP 7.2.5.5 Framed-IPv6-Prefix AVP 7.2.5.6 Framed-IPv6-Route AVP 7.2.5.7 Framed-IPv6-Pool AVP 7.2.6 IPX Access 7.2.6.1 Framed-IPX-Network AVP 7.2.7 Appletalk Access 7.2.7.1 Framed-AppleTalk-Link AVP 7.2.7.2 Framed-AppleTalk-Network AVP 7.2.7.3 Framed-AppleTalk-Zone AVP 7.2.8 ARAP Access 7.2.8.1 ARAP-Features AVP 7.2.8.2 ARAP-Zone-Access AVP 7.2.8.3 ARAP-Security AVP 7.2.8.4 ARAP-Security-Data AVP 7.3 Non-Framed Access Authorization AVPs 7.3.1 Login-IP-Host AVP Calhoun et al. expires September 2002 [Page 3]
Internet-Draft Diameter NASREQ Application March 2002 7.3.2 Login-Service AVP 7.3.3 TCP Services 7.3.3.1 Login-TCP-Port AVP 7.3.4 LAT Services 7.3.4.1 Login-LAT-Service AVP 7.3.4.2 Login-LAT-Node AVP 7.3.4.3 Login-LAT-Group AVP 7.3.4.4 Login-LAT-Port AVP 7.4 Tunneling AVPs | 7.4.1 Tunnel-Type AVP 7.4.2 Tunnel-Medium-Type AVP 7.4.3 Tunnel-Client-Endpoint AVP 7.4.4 Tunnel-Server-Endpoint AVP 7.4.5 Tunnel-Password AVP 7.4.6 Tunnel-Private-Group-ID AVP 7.4.7 Tunnel-Assignment-ID AVP 7.4.8 Tunnel-Preference AVP 7.4.9 Tunnel-Client-Auth-ID AVP 7.4.10 Tunnel-Server-Auth-ID AVP 8.0 Accounting Considerations 8.1 Accounting-Input-Octets AVP | 8.2 Accounting-Output-Octets AVP | 8.3 Acct-Session-Time AVP | 8.4 Accounting-Input-Packets AVP | 8.5 Accounting-Output-Packets AVP | 8.6 Accounting-Authentication-Type AVP 8.7 Acct-Tunnel-Connection AVP 8.8 Acct-Tunnel-Packets-Lost AVP 8.9 Accounting-EAP-Auth-Method AVP 9.0 RADIUS/Diameter Protocol Interactions 9.1 RADIUS request forwarded as Diameter request 9.2 Diameter request forwarded as RADIUS request 10.0 AVP Occurrence Table 10.1 NASREQ Command AVP Table 10.2 Accounting AVP Table 10.2.1 Framed Access 10.2.2 Non-Framed Access 11.0 IANA Considerations 11.1 Command Codes 11.2 AVP Codes 11.3 Application Identifier 11.4 NAS-Key-Binding AVP Values 11.5 NAS-Key-Direction AVP Values 11.6 NAS-Key-Type AVP Values 11.7 CHAP-Algorithm AVP Values 12.0 Security Considerations 13.0 References 14.0 Acknowledgements Calhoun et al. expires September 2002 [Page 4]
Internet-Draft Diameter NASREQ Application March 2002 15.0 Authors' Addresses 16.0 Full Copyright Statement 1.0 Introduction This document describes the Diameter application that is used for AAA in a PPP/SLIP Dial-Up and Terminal Server Access environment. This application, combined with the base protocol [2], satisfies the requirements defined in the NASREQ AAA criteria specification [24] and the ROAMOPS AAA Criteria specification [4]. This document is divided into three main sections. The first section defines the Diameter Command-Codes and AVPs that are needed to support legacy authentication protocols, those that are typically supported by RADIUS [1] servers. The second section defines the Command-Codes and AVPs necessary for a Diameter node to support PPP's Extensible Authentication Protocol (EAP) [25]. The third section contains the Authorization AVPs that are needed for the various services offered by a NAS, such as PPP dial-in, terminal server and tunneling applications, such as L2TP [16]. Given that it is expected that initial deployments of the Diameter protocol in a dial-up environment will include legacy systems, this application was carefully designed to ease the burden of servers that must perform protocol conversion between RADIUS and Diameter. This is achieved by re-using the RADIUS address space, eliminating the need to perform attribute lookups. 1.1 Requirements language In this document, the key words "MAY", "MUST", "MUST NOT", | "OPTIONAL", "RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be | interpreted as described in [12]. 1.2 Advertising application support Diameter nodes conforming to this specification MAY advertise support by including the value of one (1) in the Auth-Application-Id or the Acct-Application-Id AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer command [2]. 2.0 Supported AVPs This section lists all of the Diameter AVPs and the legacy RADIUS Calhoun et al. expires September 2002 [Page 5]
Internet-Draft Diameter NASREQ Application March 2002 attributes supported by this application. 2.1 Diameter AVPs This section will define all of the AVPs that are not backward compatible with the RADIUS protocol [1]. A Diameter message that includes one of these AVPs MAY cause interoperability issues should the request traverse a AAA node that only supports the RADIUS | protocol. However, the Diameter protocol should not be hampered from future developments due to the existing installed base. The following table describes the Diameter AVPs defined in the NASREQ application, their AVP Code values, types, possible flag values and whether the AVP MAY be encrypted. Due to space constraints, the short form IPFiltrRule is used to represent IPFilterRule. Calhoun et al. expires September 2002 [Page 6]
Internet-Draft Diameter NASREQ Application March 2002 +---------------------+ | AVP Flag rules | |----+-----+----+-----|----+ AVP Section | | |SHLD| MUST|MAY | Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr| -----------------------------------------|----+-----+----+-----|----| Accounting- 363 8.1 Unsigned64 | M | P | | V | Y | | Input-Octets | | | | | | | Accounting- 365 8.4 Unsigned64 | M | P | | V | Y | | Input-Packets | | | | | | | Accounting- 364 8.2 Unsigned64 | M | P | | V | Y | | Output-Octets | | | | | | | Accounting- 366 8.5 Unsigned64 | M | P | | V | Y | | Output-Packets | | | | | | | Accounting-EAP- 401 8.9 Enumerated | M | P | | V | Y | | Auth-Method | | | | | | | CHAP-Auth 409 3.1.1.2 Grouped | M | P | | V | Y | | CHAP-Algorithm 412 3.1.1.4 Enumerated | M | P | | V | Y | | CHAP-Ident 410 3.1.1.3 OctetString| M | P | | V | Y | | CHAP-Response 411 3.1.1.5 OctetString| M | P | | V | Y | | EAP-Payload 402 4.3 OctetString| M | P | | V | Y | NAS-Filter-Rule 400 2.1.1 IPFiltrRule| M | P | | V | Y | NAS-Key-Binding 404 2.1.6 Enumerated | M | P | | V | Y | NAS-Key-Data 405 2.1.5 OctetString| M | P | | V | N | NAS-Key- 406 2.1.3 Enumerated | M | P | | V | N | Direction | | | | | | NAS-Key-Type 407 2.1.4 Enumerated | M | P | | V | N | NAS-Key-Lifetime 413 2.1.7 Unsigned32 | M | P | | V | N | | NAS-IV 414 2.1.8 OctetString| M | P | | V | N | | NAS-Session-Key 408 2.1.2 Grouped | M | P | | V | Y | Tunneling 403 7.4 Grouped | M | P | | V | N | 2.1.1 NAS-Filter-Rule AVP The NAS-Filter-Rule AVP (AVP Code 400) is of type IPFilterRule, and provides filter rules that need to be configured on the NAS for the user. One or more such AVPs MAY be present in an authorization response. 2.1.2 NAS-Session-Key AVP The NAS-Session-Key AVP (AVP Code 408) is of type Grouped, and contains a session key distributed from Diameter servers to clients. The keys MAY be used for integrity and/or confidentiality protection between the NAS and the user. The keys MAY be distributed to the user as part of an EAP authentication exchange. Its Data field has the Calhoun et al. expires September 2002 [Page 7]
Internet-Draft Diameter NASREQ Application March 2002 following ABNF grammar: NAS-Session-Key ::= < AVP Header: 408 > { NAS-Key-Direction } { NAS-Key-Type } { NAS-Key } { NAS-Key-Data } { NAS-Key-Binding } | [ NAS-Key-Lifetime ] [ NAS-IV ] * [ AVP ] If strong authentication and confidentiality of the session keys is required, it is recommended that the CMS security application [13] be used to protect the NAS-Session-Key AVP. The NAS-Session-Key AVP MAY appear zero or more times in the AAA and DEA messages. When more than one NAS-Session-Key AVP is present in a message, either the NAS-Key-Type or the NAS-Key-Direction AVPs MUST have different values. Otherwise, the AVPs would conflict with each other. If the optional NAS-Key-Lifetime AVP (see section 2.1.7, below) is not present, then the lifetime of the NAS-Session-Key AVP is found in the Authorization-Lifetime AVP. If a re-authorization request is received prior to the expiration of the lifetime, new keys will need to be established. 2.1.3 NAS-Key-Direction AVP The NAS-Key-Direction AVP (AVP Code 406) is of type Enumerated, and specifies the direction that the traffic is to be protected with the key. The following values are supported: BIDIRECTIONAL 1 The key is used in both directions UPLINK 2 The key is used for traffic from the user DOWNLINK 3 The key is used for traffic sent to user 2.1.4 NAS-Key-Type AVP The NAS-Key-Type AVP (AVP Code 407) is of type Enumerated, and Calhoun et al. expires September 2002 [Page 8]
Internet-Draft Diameter NASREQ Application March 2002 specifies how the key is to be used. The following values are supported: CIPHER_KEY 1 The key is used to encrypt data INTEGRITY_KEY 2 The key is used to authenticate the data MASTER_CIPHER_KEY 3 The master cipher is used to derive further cipher keys MASTER_INTEGRITY_KEY 4 The master integrity is used to derive further integrity keys MASTER_KEY 5 The master can be used to derive any type of keys, but is not guaranteed to be useful for any particular crypto system. Additional processing will be required, and is not specified in this document. 2.1.5 NAS-Key-Data AVP The NAS-Key-Data AVP (AVP Code 405) is of type OctetString and contains the session key to be used between the user and the access device. 2.1.6 NAS-Key-Binding AVP The NAS-Key-Binding AVP (AVP Code 404) is of type Enumerated, and specifies the purpose for the key. A Diameter client MAY include this AVP in a request to specify to the Diameter server the type of key it desires. Responses that include the NAS-Session-Key AVP MUST include this AVP which is used to specify the type of key found in the MAS- Key-Data AVP. The following values are supported: DES 1 The key created is used to secure links using DES 3DES 2 The key created is used to secure links using Triple DES RC4-40 3 The key created is used to secure links using RC4 using 40-bit keys Calhoun et al. expires September 2002 [Page 9]
Internet-Draft Diameter NASREQ Application March 2002 RC4-128 4 The key created is used to secure links using RC4 with 128-bit keys 2.1.7 NAS-Key-Lifetime AVP The NAS-Key-Lifetime AVP (AVP Code 413) is of type Unsigned32 and | represents the period of time (in seconds) for which the session key is valid. The session key MUST NOT be used if the lifetime has expired; if the key lifetime expires while the session to which it applies is still active, either the session key MUST be changed or the or the session MUST be terminated. 2.1.8 NAS-IV AVP The NAS-IV AVP (AVP Code 414) is of type OctetString. Its contents | MAY be used as an initialization vector (IV) by cryptographic algorithms (e.g., block ciphers). 2.2 Legacy RADIUS Attributes The Diameter protocol reserves the AVP Codes 0-255 for "legacy | RADIUS" support. The following table contains the RADIUS attributes supported by this Diameter application, their AVP code values, types, possible flag values and whether the AVP MAY be encrypted. RADIUS attributes not listed are not supported by the Diameter protocol. Due to space constraints, the short form DiamIdent is used to represent DiameterIdentity. Calhoun et al. expires September 2002 [Page 10]
Internet-Draft Diameter NASREQ Application March 2002 +---------------------+ | AVP Flag rules | |----+-----+----+-----|----+ AVP Section | | |SHLD| MUST|MAY | Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr| -----------------------------------------|----+-----+----+-----|----| Accounting- 45 8.6 Unsigned32 | M | P | | V | Y | Authentication-Type | | | | | | Acct-Session-Time 46 8.3 Unsigned32 | M | P | | V | Y | | Acct-Tunnel- 68 8.7 OctetString| M | P | | V | Y | Connection | | | | | | Acct-Tunnel- 86 8.8 Unsigned32 | M | P | | V | Y | Packets-Lost | | | | | | ARAP-Challenge- 84 3.1.2.1 OctetString| M | P | | V | Y | Response | | | | | | ARAP-Features 71 7.2.8.1 OctetString| M | P | | V | Y | ARAP-Password 70 3.1.1.7 OctetString| M | P | | V | Y | ARAP-Security 73 7.2.8.3 Unsigned32 | M | P | | V | Y | ARAP-Security- 74 7.2.8.4 OctetString| M | P | | V | Y | Data | | | | | | ARAP-Zone-Access 72 7.2.8.2 Enumerated | M | P | | V | Y | Callback-Id 20 6.4 UTF8String | M | P | | V | Y | Callback-Number 19 6.3 UTF8String | M | P | | V | Y | Called-Station-Id 30 6.6 UTF8String | M | P | | V | Y | Calling-Station- 31 6.7 UTF8String | M | P | | V | Y | Id | | | | | | CHAP-Challenge 60 3.1.1.6 OctetString| M | P | | V | Y | | Connect-Info 77 6.10 UTF8String | M | P | | V | Y | | Filter-Id 11 6.2 UTF8String | M | P | | V | Y | Framed-Appletalk- 37 7.2.7.1 Unsigned32 | M | P | | V | Y | Link | | | | | | Framed-Appletalk- 38 7.2.7.2 Unsigned32 | M | P | | V | Y | Network | | | | | | Framed-Appletalk- 39 7.2.7.3 OctetString| M | P | | V | Y | Zone | | | | | | Framed- 13 7.2.4 Enumerated | M | P | | V | Y | Compression | | | | | | Framed- 96 7.2.5.4 Unsigned64 | M | P | | V | Y | Interface-Id | | | | | | Framed-IPv6-Pool 100 7.2.5.7 UTF8String | M | P | | V | Y | Framed-IPv6- 97 7.2.5.5 IPAddress | M | P | | V | Y | Prefix | | | | | | Framed-IPv6- 99 7.2.5.6 UTF8String | M | P | | V | Y | Route | | | | | | Framed-IP-Address 8 7.2.5.1 IPAddress | M | P | | V | Y | Framed-IP-Netmask 9 7.2.5.2 IPAddress | M | P | | V | Y | Framed-IP-Route 22 7.2.5.3 UTF8String | M | P | | V | Y | Calhoun et al. expires September 2002 [Page 11]
Internet-Draft Diameter NASREQ Application March 2002 +---------------------+ | AVP Flag rules | |----+-----+----+-----|----+ AVP Section | | |SHLD| MUST|MAY | Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr| -----------------------------------------|----+-----+----+-----|----| Framed-IPX- 23 7.2.6.1 UTF8String | M | P | | V | Y | Network | | | | | | Framed-MTU 12 7.2.3 Unsigned32 | M | P | | V | Y | Framed-Protocol 7 7.2.1 Enumerated | M | P | | V | Y | Framed-Routing 10 7.2.2 Enumerated | M | P | | V | Y | Idle-Timeout 28 6.5 Unsigned32 | M | P | | V | Y | Login-IP-Host 14 7.3.1 IPAddress | M | P | | V | Y | Login-LAT-Group 36 7.3.4.3 OctetString| M | P | | V | Y | Login-LAT-Node 35 7.3.4.2 OctetString| M | P | | V | Y | Login-LAT-Port 63 7.3.4.4 OctetString| M | P | | V | Y | Login-LAT-Service 34 7.3.4.1 OctetString| M | P | | V | Y | Login-Service 15 7.3.2 Enumerated | M | P | | V | Y | Login-TCP-Port 16 7.3.3.1 Unsigned32 | M | P | | V | Y | NAS-Identifier 32 2.2.2 UTF8String | M | P | | V | Y | | NAS-IP-Address 4 2.2.1 IPAddress | M | P | | V | Y | NAS-Port 5 6.1 Unsigned32 | M | P | | V | Y | NAS-Port-Type 61 6.8 Unsigned32 | M | P | | V | Y | Password-Retry 75 3.1.2.2 Unsigned32 | M | P | | V | Y | Port-Limit 62 6.9 Unsigned32 | M | P | | V | Y | Prompt 76 3.1.2.3 Enumerated | M | P | | V | Y | Reply-Message 18 3.2 UTF8String | M | P | | V | Y | Service-Type 6 7.1 Enumerated | M | P | | V | Y | State 24 2.2.3 OctetString| M | P | | V | Y | Tunnel- 82 7.4.7 OctetString| M | P | | V | Y | Assignment-Id | | | | | | Tunnel-Client- 90 7.4.9 Unsigned32 | M | P | | V | Y | Auth-ID | | | | | | Tunnel-Client- 66 7.4.3 UTF8String | M | P | | V | Y | Endpoint | | | | | | Tunnel-Medium- 65 7.4.2 Enumerated | M | P | | V | Y | Type | | | | | | Tunnel-Password 69 7.4.5 OctetString| M | P | | V | Y | Tunnel-Preference 83 7.4.8 Unsigned32 | M | P | | V | Y | Tunnel-Private- 81 7.4.6 UTF8String | M | P | | V | Y | Group-ID | | | | | | Tunnel-Server- 91 7.4.10 OctetString| M | P | | V | Y | Auth-ID | | | | | | Tunnel-Server- 67 7.4.4 UTF8String | M | P | | V | Y | Endpoint | | | | | | Tunnel-Type 64 7.4.1 Enumerated | M | P | | V | Y | User-Password 2 3.1.1.1 OctetString| M | P | | V | Y | Calhoun et al. expires September 2002 [Page 12]
Internet-Draft Diameter NASREQ Application March 2002 The AVPs defined in this section SHOULD only used when a Diameter/RADIUS gateway function is invoked, and are not used in the Diameter protocol. 2.2.1 NAS-IP-Address AVP The NAS-IP-Address AVP (AVP Code 4) [1] is of type IPAddress, and contains the IP Address of the NAS providing service to the user. When this AVP is present, the Origin-Host AVP DOES NOT represent the NAS providing service to the user. Note that this AVP SHOULD only added by a RADIUS/Diameter protocol gateway (see Section 9.0). 2.2.2 NAS-Identifier AVP The NAS-Identifier AVP (AVP Code 32) [1] is of type UTF8String and | contains the identity of the NAS providing service to the user. When this AVP is present, the Origin-Host AVP DOES NOT represent the NAS providing service to the user. Note that this AVP SHOULD only added by a RADIUS/Diameter protocol gateway (see Section 9.0). This AVP | may only be used in AAR and DER messages. 2.2.3 State AVP The State AVP (AVP Code 24) is of type OctetString and is used to transmit the contents of the RADIUS State attribute, and no interpretation of the contents should be made. Note that this AVP SHOULD only added by a RADIUS/Diameter protocol gateway (see Section 9.0). 3.0 Legacy RADIUS Authentication Support This section defines the new Command-Code [2] values required to support the legacy authentication protocols (i.e. PAP, CHAP), as well as the AVPs that are necessary to carry the authentication information in the Diameter protocol. The functionality defined here provides a RADIUS-like AAA service, over a more reliable and secure transport, as defined in the base protocol [2]. Unlike the RADIUS protocol [1], the Diameter protocol does not require authentication information to be contained in a request from the client. Therefore, it is possible to send a request for authorization only. The type of service depends upon the Auth- Request-Type AVP. This difference MAY cause operational issues in environments that need RADIUS interoperability, and it MAY be Calhoun et al. expires September 2002 [Page 13]
Internet-Draft Diameter NASREQ Application March 2002 necessary that protocol conversion gateways add some authentication information when transmitting to a RADIUS server. The Diameter protocol allows for users to be periodically re- authenticated and/or re-authorized. In such instances, the Session-Id AVP in the AAR message MUST be the same as the one present in the original authentication/authorization message. A Diameter server informs the NAS of the maximum time allowed before re-authentication | or re-authorization via the Authorization-Lifetime AVP [1]. Note, | however, that the Authorization-Lifetime AVP SHOULD NOT be used if | the AAR or DER message contained a NAS-IP-Address or NAS-Identifier | AVP since this would mean that the NAS is using RADIUS which does not | support re-authentication or re-authorization. A NAS MUST re-authenticate and/or authorize after the period provided by the server. Furthermore, it is possible for Diameter servers to issue an unsolicited re-authentication and/or re-authorization by issuing an Re-Auth-Request message to the NAS. Upon receipt of such a message, the NAS is instructed to issue a request to re-authenticate and/or re-authorize the client. 3.1 Command-Codes Values This section defines new Command-Code [2] values that MUST be supported by all Diameter implementations that conform to this specification. The following Command Codes are defined in this section: Command-Name Abbrev. Code Reference -------------------------------------------------------- AA-Answer AAA 265 3.1.2 AA-Request AAR 265 3.1.1 3.1.1 AA-Request (AAR) Command The AA-Request message (AAR), indicated by the Command-Code field set to 265 and the 'R' bit set in the Command Flags field, is used in order to request authentication and/or authorization for a given PPP user. The type of request is identified through the Auth-Request-Type AVP, and the default mode is both authentication and authorization. If Authentication is requested the User-Name attribute SHOULD be present, as well as any additional authentication AVPs that would carry the password information. A request for authorization only SHOULD include the information from which the authorization will be | performed, such as the User-Name, Called-Station-Id, or Calling- | Calhoun et al. expires September 2002 [Page 14]
Internet-Draft Diameter NASREQ Application March 2002 Station-Id AVPs. Certain networks MAY use different AVPs for authorization purposes. A request for authorization will include some AVPs defined in sections 2.0, 6.0 and 7.0. It is possible for a single session to be authorized first, then | followed by an authentication request. However, the inverse SHOULD NOT be permitted. This AA-Request message MAY be the result of a multi-round authentication exchange, which occurs when the AAA is received with the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH. A subsequent AAR message SHOULD be sent, with the User-Password AVP that includes the user's response to the prompt, and MUST include any State AVPs that were present in the AAA. Message Format <AA-Request> ::= < Diameter Header: 265, REQ, PXY > < Session-Id > { Auth-Application-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Auth-Request-Type } [ NAS-Port ] | [ Origin-State-Id ] [ Destination-Host ] [ NAS-IP-Address ] | [ NAS-Identifier ] [ NAS-Port-Type ] [ Port-Limit ] [ User-Name ] [ User-Password ] [ Service-Type ] | [ Idle-Timeout ] [ State ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] [ Auth-Session-State ] [ Session-Timeout ] [ NAS-Key-Binding ] [ Callback-Number ] [ Called-Station-Id ] [ Calling-Station-Id ] [ Connect-Info ] [ CHAP-Auth ] [ CHAP-Challenge ] * [ Framed-Compression ] Calhoun et al. expires September 2002 [Page 15]
Internet-Draft Diameter NASREQ Application March 2002 [ Framed-Interface-Id ] * [ Framed-IPv6-Prefix ] [ Framed-IP-Address ] | [ Framed-IP-Netmask ] [ Framed-MTU ] | [ Framed-Protocol ] [ ARAP-Password ] | [ ARAP-Security ] * [ ARAP-Security-Data ] * [ Login-IP-Host ] [ Login-LAT-Group ] [ Login-LAT-Node ] [ Login-LAT-Port ] [ Login-LAT-Service ] * [ Tunneling ] * [ Proxy-Info ] * [ Route-Record ] * [ AVP ] 3.1.1.1 User-Password AVP The User-Password AVP (AVP Code 2) is of type OctetString and contains the password of the user to be authenticated, or the user's input in a multi-round authentication exchange. The User-Password AVP MUST be encrypted using the methods described in [13], or where [13] isn't applied, the whole DIAMETER message flow MUST be encrypted using IPsec and/or TLS as described in [2]. Unless this AVP is used for one-time passwords, the User-Password AVP SHOULD NOT be used in non-trusted proxy environments. The clear-text password (prior to encryption) MUST NOT be longer than 128 bytes in length. 3.1.1.2 CHAP-Auth AVP The CHAP-Auth AVP (AVP Code 409) is of type Grouped and contains the information necessary to authenticate a user using the PPP Challenge- Handshake Authentication Protocol (CHAP) [6]. If the CHAP-Auth AVP is found in a message, the CHAP-Challenge AVP (see section 3.1.1.6) MUST be present as well. The AVP containing the CHAP response depends upon the value of the CHAP-Algorithm AVP (see section 3.1.1.4 for more info). Its Data field has the following ABNF grammar: CHAP-Auth ::= < AVP Header: 409 > { CHAP-Algorithm } Calhoun et al. expires September 2002 [Page 16]
Internet-Draft Diameter NASREQ Application March 2002 { CHAP-Ident } [ CHAP-Response ] * [ AVP ] | 3.1.1.3 CHAP-Ident AVP The CHAP-Ident AVP (AVP Code 410) is of type OctetString and contains the one octet CHAP Identifier used in the computation of the CHAP response [6]. 3.1.1.4 CHAP-Algorithm AVP The CHAP-Algorithm AVP (AVP Code 412) is of type Enumerated and contains the algorithm identifier used in the computation of the CHAP response [6]. The following values are currently supported: CHAP with MD5 5 The CHAP response is computed using the procedure described in | [6]. The CHAP-Response AVP MUST be present in the CHAP-Auth AVP. 3.1.1.5 CHAP-Response AVP The CHAP-Response AVP (AVP Code 411) is of type OctetString and contains the 16 octet authentication data provided by the user in response to the CHAP challenge [16]. The actual computation of the CHAP response can be found in [6]. 3.1.1.6 CHAP-Challenge AVP The CHAP-Challenge AVP (AVP Code 60) is of type OctetString and contains the CHAP Challenge sent by the NAS to a PPP Challenge- Handshake Authentication Protocol (CHAP) [6] user. 3.1.1.7 ARAP-Password AVP The ARAP-Password AVP (AVP Code 70) is of type OctetString and is only present when the Framed-Protocol AVP (see Section 7.2.1) is included in the message and is set to ARAP. This AVP MUST NOT be present if either the User-Password or the CHAP-Auth AVP is present. See [32] for more information on the contents of this AVP. Calhoun et al. expires September 2002 [Page 17]
Internet-Draft Diameter NASREQ Application March 2002 3.1.2 AA-Answer (AAA) Command The AA-Answer (AAA) message, indicated by the Command-Code field set to 265 and the 'R' bit cleared in the Command Flags field, is sent in response to the AA-Request message. If authorization was requested, a successful response will include the authorization AVPs appropriate for the service being provided, as defined in section 2.0, 6.0 and 7.0 For authentication exchanges that require more than a single round trip, the server MUST set the Result-Code AVP to DIAMETER_MULTI_ROUND_AUTH. An AAA message with this result code MAY include one or more Reply-Message and MAY include zero or one State AVPs. When possible, authentication mechanisms that include more than a single authentication round trip SHOULD use EAP (see section 4.0) If the Reply-Message AVP was present, the access device SHOULD display the text message to the user, and MUST prompt the user for a response. If the access device is unable to prompt the user for a new response, which could be achieved via PAP, it MUST treat this answer as an error, and deny access. Message Format <AA-Answer> ::= < Diameter Header: 265, PXY > < Session-Id > { Auth-Application-Id } { Auth-Request-Type } { Result-Code } { Origin-Host } { Origin-Realm } [ User-Name ] [ Service-Type ] | [ Error-Message ] [ Error-Reporting-Host ] [ Idle-Timeout ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] [ Auth-Session-State ] [ Re-Auth-Request-Type ] [ Session-Timeout ] [ State ] * [ Reply-Message ] [ Origin-State-Id ] * [ Filter-Id ] * [ NAS-Session-Key ] [ Password-Retry ] Calhoun et al. expires September 2002 [Page 18]
Internet-Draft Diameter NASREQ Application March 2002 [ Port-Limit ] | [ Prompt ] [ ARAP-Challenge-Response ] [ ARAP-Features ] [ ARAP-Security ] | * [ ARAP-Security-Data ] | [ ARAP-Zone-Access ] [ Callback-Id ] [ Callback-Number ] [ Framed-Appletalk-Link ] * [ Framed-Appletalk-Network ] [ Framed-Appletalk-Zone ] * [ Framed-Compression ] [ Framed-Interface-Id ] * [ Framed-IPv6-Prefix ] [ Framed-IPv6-Pool ] * [ Framed-IPv6-Route ] [ Framed-IP-Address ] [ Framed-IP-Netmask ] * [ Framed-IP-Route ] | [ Framed-IPX-Network ] | [ Framed-MTU ] | [ Framed-Protocol ] | [ Framed-Routing ] | * [ Login-IP-Host ] [ Login-LAT-Group ] [ Login-LAT-Node ] [ Login-LAT-Port ] [ Login-LAT-Service ] [ Login-Service ] | [ Login-TCP-Port ] | * [ NAS-Filter-Rule ] * [ Tunneling ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Max-Cache-Time ] * [ Proxy-Info ] * [ AVP ] 3.1.2.1 ARAP-Challenge-Response AVP The ARAP-Challenge-Response AVP (AVP Code 84) is of type OctetString and is only present when the Framed-Protocol AVP (see Section 7.2.1) is included in the message and is set to ARAP. This AVP contains an 8 octet response to the dial-in client's challenge. The RADIUS server calculates this value by taking the dial-in client's challenge from the high order 8 octets of the ARAP-Password AVP and performing DES Calhoun et al. expires September 2002 [Page 19]
Internet-Draft Diameter NASREQ Application March 2002 encryption on this value with the authenticating user's password as the key. If the user's password is less than 8 octets in length, the password is padded at the end with NULL octets to a length of 8 before using it as a key. 3.1.2.2 Password-Retry AVP The Password-Retry AVP (AVP Code 75) is of type Unsigned32 and MAY be included in the AA-Answer if the Result-Code indicates an authentication failure. The value of this AVP indicates how many authentication attempts a user may be permitted before being disconnected. This AVP is primarily intended for use when the Framed- Protocol AVP (see Section 7.2.1) is set to ARAP. 3.1.2.3 Prompt AVP The Prompt AVP (AVP Code 76) is of type Enumerated, and MAY be present in the AA-Answer message. When present, it is used by the NAS to determine whether the user's response, when entered, should be echoed. The supported values are listed in [33]. 3.2 Reply-Message AVP The Reply-Message AVP (AVP Code 18) is of type UTF8String, and contains text which MAY be displayed to the user. When used in an AA-Answer message with a successful Result-Code AVP it indicates the success message. When found in the same message with a Result-Code other than Diameter-SUCCESS it contains the failure message. The Reply-Message AVP MAY indicate a dialog message to prompt the user before another AA-Request attempt. When used in an AA-Answer, it MAY indicate a dialog message to prompt the user for a response. Multiple Reply-Message's MAY be included and if any are displayed, they MUST be displayed in the same order as they appear in the message. 4.0 Extensible Authentication Protocol Support The Extensible Authentication Protocol (EAP), described in [25], provides a standard mechanism for support of extensible authentication methods. Through the use of EAP, support for a number Calhoun et al. expires September 2002 [Page 20]
Internet-Draft Diameter NASREQ Application March 2002 of authentication schemes may be added, including smart and token cards, Kerberos, Public Key, One Time Passwords, and others. This section describes the Command-Codes values and AVPs that are required for an EAP payload to be encapsulated within the Diameter protocol. Since authentication occurs between the EAP client and its home Diameter server, end-to-end authentication is achieved, reducing the possibility for fraudulent authentication, such as replay and man-in-the-middle attacks. End-to-end authentication also provides for mutual (bi-directional) authentication, which is not possible with PAP and CHAP in a roaming PPP environment. The EAP conversation between the authenticating peer and the access device begins with the initiation of EAP within a link layer, such as PPP or 802.1x. Once EAP has been initiated, the access device will typically send to the Diameter server a Diameter-EAP-Request message with a NULL EAP-Payload AVP, signifying an EAP-Start. The Port number and the identity of the access device (e.g. Origin-Host or NAS- Identifier) MUST be included in the Diameter-EAP-Request message. If the Diameter home server supports EAP, it MUST respond with a Diameter-EAP-Answer message containing an EAP-Payload AVP that includes an encapsulated EAP payload [25], and the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH, signifying that a subsequent request is expected. The EAP payload is forwarded by the access device to the EAP client. The initial Diameter-EAP-Answer in a multi-round exchange normally includes an EAP-Request/Identity, requesting the EAP client to identify itself. Upon receipt of the EAP client's EAP-Response [25], the access device will then issue a second Diameter-EAP-Request message, with the client's EAP payload encapsulated within the EAP- Payload AVP. A preferred approach is for the access device to issue the EAP- Request/Identity message to the EAP client, and forward the EAP- Response/Identity packet, encapsulated within the EAP-Payload AVP, as a Diameter-EAP-Request to the Diameter server. This alternative reduces the number of Diameter message round trips, and is compatible with roaming environments, since the Destination-Realm is needed by Diameter agents for routing purposes. Note that this alternative cannot be universally employed, as there are circumstances where a user's identity is not needed (such as when authorization occurs based on a calling or called phone number). The conversation continues until the Diameter server sends a Diameter-EAP-Answer with a Result-Code AVP indicating success or failure, and an optional EAP-Payload. The Result-Code AVP is used by Calhoun et al. expires September 2002 [Page 21]
Internet-Draft Diameter NASREQ Application March 2002 the access device to determine whether service is to be provided to the EAP client. The access device MUST NOT rely on the contents of the optional EAP-Payload to determine whether service is to be provided. A Diameter-EAP-Answer message containing an EAP-Payload of type EAP- Success or EAP-Failure MUST NOT have the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH. If authorization was requested, a successful Diameter-EAP-Answer MUST also include the appropriate authorization AVPs required for the service requested (see sections 2.0, 6.0 and 7.0). Diameter-EAP- Answer messages whose Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH MAY include authorization AVPs. Unless the access device interprets the EAP-Response/Identity packet returned by the authenticating peer, it will not have access to the user's identity. Therefore, the Diameter Server SHOULD return the user's identity by inserting it in the User-Name attribute of subsequent Diameter-EAP-Answer packets. Without the user's identity, the Session-Id AVP MAY be used for accounting and billing, however operationally this MAY be very difficult to manage. A home Diameter server MAY request EAP re-authentication by issuing the Re-Auth-Request [2] message to the Diameter client. Should an EAP authentication session be interrupted due to a home server failure, the session MAY be directed to an alternate server, but the authentication session will have to be restarted from the beginning. If a response is received with the Result-Code set to DIAMETER_COMMAND_UNSUPPORTED [2], it is an indication that the Diameter server in the home realm does not support EAP. If possible, the access device MAY attempt to negotiate another authentication protocol, such as PAP or CHAP. An access device SHOULD be cautious when determining whether a less secure authentication protocol will be used, since this could be a result of a bidding down attack. 4.1 Alternative uses Currently the conversation between the backend authentication server and the Diameter server is proprietary because of lack of standardization. In order to increase standardization and provide interoperability between Diameter vendors and backend security vendors, it is recommended that Diameter-encapsulated EAP be used for this conversation. Calhoun et al. expires September 2002 [Page 22]
Internet-Draft Diameter NASREQ Application March 2002 This has the advantage of allowing the Diameter server to support EAP without the need for authentication-specific code within the Diameter server. Authentication-specific code can then reside on a backend authentication server instead. In the case where Diameter-encapsulated EAP is used in a conversation between a Diameter server and a backend authentication server, the latter will typically return an Diameter-EAP-Answer/EAP-Payload/EAP- Success message without inclusion of the expected authorization AVPs required in a successful response. This means that the Diameter server MUST add these attributes prior to sending an Diameter-EAP- Answer/EAP-Payload/EAP-Success message to the access device. 4.2 Command-Codes Values This section defines new Command-Code [2] values that MUST be supported by all Diameter implementations conforming to this specification. The following Command Codes are defined in this section: Command-Name Abbrev. Code Reference -------------------------------------------------------- Diameter-EAP-Answer DEA 268 4.2.2 Diameter-EAP-Request DER 268 4.2.1 4.2.1 Diameter-EAP-Request (DER) Command The Diameter-EAP-Request (DER) command, indicated by the Command-Code field set to 268 and the 'R' bit set in the Command Flags field, is sent by a Diameter client to a Diameter server and conveys an EAP- Response [25] from the EAP client. The Diameter-EAP-Request MUST contain one EAP-Payload AVP, which contains the actual EAP payload. An EAP-Payload AVP with no data MAY be sent to the Diameter server to initiate an EAP authentication session. The DER message MAY be the result of a multi-round authentication exchange, which occurs when the DEA is received with the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH. A subsequent DER message MUST include any State AVPs that were present in the DEA. For re- authentication, it is recommended that the Identity request be skipped in order to reduce the number of authentication round trips. This is only possible when the user's identity is already known by the home Diameter server. Calhoun et al. expires September 2002 [Page 23]
Internet-Draft Diameter NASREQ Application March 2002 Message Format <Diameter-EAP-Request> ::= < Diameter Header: 268, REQ, PXY > < Session-Id > { Auth-Application-Id } { Origin-Host } { Origin-Realm } { Destination-Realm } { Auth-Request-Type } { EAP-Payload } [ NAS-Port ] | [ Destination-Host ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] [ Auth-Session-State ] [ Session-Timeout ] [ User-Name ] [ Service-Type ] | [ Idle-Timeout ] [ NAS-IP-Address ] | [ NAS-Identifier ] [ NAS-Port-Type ] [ Port-Limit ] [ State ] [ Origin-State-Id ] [ NAS-Key-Binding ] [ Callback-Number ] [ Called-Station-Id ] [ Calling-Station-Id ] [ Connect-Info ] * [ Framed-Compression ] [ Framed-Interface-Id ] * [ Framed-IPv6-Prefix ] [ Framed-IP-Address ] | [ Framed-IP-Netmask ] [ Framed-MTU ] | [ Framed-Protocol ] * [ Tunneling ] | * [ Proxy-Info ] * [ Route-Record ] * [ AVP ] 4.2.2 Diameter-EAP-Answer (DEA) Command The Diameter-EAP-Answer (DEA) message, indicated by the Command-Code field set to 268 and the 'R' bit cleared in the Command Flags field, is sent by the Diameter server to the client for one of the following Calhoun et al. expires September 2002 [Page 24]
Internet-Draft Diameter NASREQ Application March 2002 reasons: 1) The message is part of a multi-round authentication exchange, and the server is expecting a subsequent Diameter-EAP-Request. This is indicated by setting the Result-Code to DIAMETER_MULTI_ROUND_AUTH, and MAY include zero or more State AVPs. 2) the EAP client has been successfully authenticated and authorized, in which case the message MUST include the Result- Code AVP indicating success, and SHOULD include an EAP-Payload of type EAP-Success. This event MUST cause the access device to provide service to the EAP client. 3) The EAP client has not been successfully authenticated and/or authorized, and the Result-Code AVP is set to indicate failure. This message SHOULD include an EAP-Payload, but this AVP is not used to determine whether service is to be provided. If the message from the Diameter client included a request for authorization, a successful response MUST include the authorization AVPs that are relevant to the service being provided. Message Format <Diameter-EAP-Answer> ::= < Diameter Header: 268, PXY > < Session-Id > { Auth-Application-Id } { Result-Code } { Origin-Host } { Origin-Realm } { Auth-Request-Type } [ Error-Reporting-Host ] [ EAP-Payload ] [ User-Name ] [ Service-Type ] | [ Idle-Timeout ] [ Authorization-Lifetime ] [ Auth-Grace-Period ] [ Auth-Session-State ] [ Re-Auth-Request-Type ] [ Session-Timeout ] [ State ] | [ Origin-State-Id ] * [ Filter-ID ] | * [ NAS-Session-Key ] [ Callback-Id ] [ Callback-Number ] [ Framed-Appletalk-Link ] * [ Framed-Appletalk-Network ] Calhoun et al. expires September 2002 [Page 25]
Internet-Draft Diameter NASREQ Application March 2002 [ Framed-Appletalk-Zone ] * [ Framed-Compression ] [ Framed-Interface-Id ] * [ Framed-IPv6-Prefix ] [ Framed-IPv6-Pool ] * [ Framed-IPv6-Route ] [ Framed-IP-Address ] [ Framed-IP-Netmask ] * [ Framed-IP-Route ] [ Framed-IPX-Network ] [ Framed-MTU ] [ Framed-Protocol ] | [ Framed-Routing ] | * [ NAS-Filter-Rule ] * [ Tunneling ] * [ Redirect-Host ] [ Redirect-Host-Usage ] [ Redirect-Max-Cache-Time ] [ Port-Limit ] | * [ Proxy-Info ] * [ AVP ] 4.3 EAP-Payload AVP The EAP-Payload AVP (AVP Code 402) is of type OctetString and is used to encapsulate the actual EAP payload [25] that is being exchanged between the EAP client and the home Diameter server. 5.0 Diameter Session Termination When a Network Access Server (NAS) receives an indication that a user's session is being disconnected (e.g. LCP Terminate is received), the NAS MUST issue a Session-Termination-Request (STR) [2] to its Diameter Server. This will ensure that any resources maintained on the servers is freed appropriately. Further, a NAS that receives a Abort-Session-Request (ASR) [2] MUST issue an STR if the session requested is active, and disconnect the PPP (or tunneling) session. 6.0 Call and Session Information This section contains the authorization AVPs that are needed to identify call and session information, and allows the server to set constraints on a session. Calhoun et al. expires September 2002 [Page 26]
Internet-Draft Diameter NASREQ Application March 2002 6.1 NAS-Port AVP The NAS-Port AVP (AVP Code 5) is of type Unsigned32 and contains the physical port number of the NAS which is authenticating the user, and is normally only present in an authentication and/or authorization request. Note that this is using "port" in its sense of a physical connection on the NAS, not in the sense of a TCP or UDP port number. Either NAS-Port or NAS-Port-Type (AVP Code 61) or both SHOULD be present in the request, if the NAS differentiates among its ports. 6.2 Filter-Id AVP The Filter-Id AVP (AVP Code 11) is of type UTF8String, and contains the name of the filter list for this user. Zero or more Filter-Id AVPs MAY be sent in an authorization answer. Identifying a filter list by name allows the filter to be used on different NASes without regard to filter-list implementation details. However, this AVP is not roaming friendly since filter naming differs from one service provider to another. In non-RADIUS environments, it is RECOMMENDED that the NAS-Filter- | Rule AVP be used instead. 6.3 Callback-Number AVP The Callback-Number AVP (AVP Code 19) is of type UTF8String, and contains a dialing string to be used for callback. It MAY be used in an authentication and/or authorization request as a hint to the server that a Callback service is desired, but the server is not required to honor the hint in the corresponding response. The codification of the range of allowed usage of this field is outside the scope of this specification. 6.4 Callback-Id AVP The Callback-Id AVP (AVP Code 20) is of type UTF8String, and contains the name of a place to be called, to be interpreted by the NAS. This AVP MAY be present in an authentication and/or authorization response. This AVP is not roaming friendly since it assumes that the Callback- Id is configured on the NAS. It is therefore preferable to use the Callback-Number AVP instead. Calhoun et al. expires September 2002 [Page 27]
Internet-Draft Diameter NASREQ Application March 2002 6.5 Idle-Timeout AVP The Idle-Timeout AVP (AVP Code 28) is of type Unsigned32 and sets the maximum number of consecutive seconds of idle connection allowed to the user before termination of the session or prompt. It MAY be used in an authentication and/or authorization request (or challenge) as a hint to the server that an idle timeout is desired, but the server is not required to honor the hint in the corresponding response. 6.6 Called-Station-Id AVP The Called-Station-Id AVP (AVP Code 30) is of type UTF8String, and allows the NAS to send in the request the phone number that the user called, using Dialed Number Identification (DNIS) or a similar technology. Note that this may be different from the phone number the call comes in on. It SHOULD only be present in authentication and/or authorization requests. If the Auth-Request-Type AVP is set to authorization-only and the User-Name AVP is absent, the Diameter Server MAY perform authorization based on this field. This can be used by a NAS to request whether a call should be answered based on the DNIS. The codification of the range of allowed usage of this field is outside the scope of this specification. 6.7 Calling-Station-Id AVP The Calling-Station-Id AVP (AVP Code 31) is of type UTF8String, and allows the NAS to send in the request the phone number that the call came from, using Automatic Number Identification (ANI) or a similar technology. It SHOULD only be present in authentication and/or authorization requests. If the Auth-Request-Type AVP is set to authorization-only and the User-Name AVP is absent, the Diameter Server MAY perform authorization based on this field. This can be used by a NAS to request whether a call should be answered based on the ANI. The codification of the range of allowed usage of this field is outside the scope of this specification. 6.8 NAS-Port-Type AVP Calhoun et al. expires September 2002 [Page 28]
Internet-Draft Diameter NASREQ Application March 2002 The NAS-Port-Type AVP (AVP Code 61) is of type Unsigned32 and contains the type of the physical port of the NAS which is authenticating the user. It can be used instead of or in addition to the NAS-Port (5) AVP. This AVP SHOULD only be used in authentication and/or authorization requests. This AVP MAY be combined with the NAS- Port AVP to assist in differentiating its ports. The supported values are defined in [33]. 6.9 Port-Limit AVP The Port-Limit AVP (AVP Code 62) is of type Unsigned32 and sets the maximum number of ports to be provided to the user by the NAS. It MAY be used in an authentication and/or authorization request as a hint to the server that multilink PPP [9] service is desired, but the server is not required to honor the hint in the corresponding response. 6.10 Connect-Info AVP The Connect-Info AVP (AVP Code 77) is of type UTF8String, and is sent in the AA-Request message, and indicates the nature of the user's connection. The connection speed SHOULD be included at the beginning of the first Connect-Info AVP in the message. If the transmit and receive connection speeds differ, they may both be included in the first AVP with the transmit speed first (the speed the NAS modem transmits at), a slash (/), the receive speed, then optionally other information. 7.0 Service Specific Authorization AVPs This section contains the RADIUS authorization AVPs that are supported in the Diameter protocol. The Service-Type AVP SHOULD be | present in all messages, and based on the value of the Service-Type AVP, additional AVPs defined in sections 7.2, 7.3 and 7.4 MAY be present. 7.1 Service-Type AVP The Service-Type AVP (AVP Code 6) is of type Enumerated and contains the type of service the user has requested, or the type of service to be provided. One such AVP MAY be present in an authentication and/or authorization request or response. A NAS is not required to implement all of these service types, and MUST treat unknown or unsupported Calhoun et al. expires September 2002 [Page 29]
Internet-Draft Diameter NASREQ Application March 2002 Service-Types as though a response with a Result-Code other than Diameter-SUCCESS had been received instead. When used in a request, the Service-Type AVP SHOULD be considered to be a hint to the server that the NAS has reason to believe the user would prefer the kind of service indicated, but the server is not required to honor the hint. The following values have been defined for the Service-Type AVP: The complete list of defined values can be found in [1] and [33]. The following values are extracted from [1], and are listed here since they are further qualified: Login 1 The user should be connected to a host. The message MAY include additional AVPs defined in section 7.3. Framed 2 A Framed Protocol should be started for the User, such as PPP or SLIP. The message MAY include additional AVPs defined in section 7.2, or 7.4 for tunneling services. Callback Login 3 The user should be disconnected and called back, then connected to a host. The message MAY include additional AVPs defined in section 7.3. Callback Framed 4 The user should be disconnected and called back, then a Framed Protocol should be started for the User, such as PPP or SLIP. The message MAY include additional AVPs defined in section 7.2, or 7.4 for tunneling services. 7.2 Framed Access Authorization AVPs This section contains the authorization AVPs that are necessary to support framed access, such as PPP, SLIP, etc. AVPs defined in this section MAY be present in a message if the Service-Type AVP was set to "Framed" or "Callback Framed". 7.2.1 Framed-Protocol AVP The Framed-Protocol AVP (AVP Code 7) is of type Enumerated and contains the framing to be used for framed access. This AVP MAY be present in both requests and responses. The supported values are listed in [33]. Calhoun et al. expires September 2002 [Page 30]
Internet-Draft Diameter NASREQ Application March 2002 7.2.2 Framed-Routing AVP The Framed-Routing AVP (AVP Code 10) is of type Enumerated and contains the routing method for the user, when the user is a router to a network. This AVP SHOULD only be present in authorization responses. The supported values are listed in [33]. 7.2.3 Framed-MTU AVP The Framed-MTU AVP (AVP Code 12) is of type Unsigned32 and contains the Maximum Transmission Unit to be configured for the user, when it is not negotiated by some other means (such as PPP). This AVP SHOULD only be present in authorization responses. The MTU value MUST be between the range of 64 and 65535. 7.2.4 Framed-Compression AVP The Framed-Compression AVP (AVP Code 13) is of type Enumerated and contains the compression protocol to be used for the link. It MAY be used in an authorization request as a hint to the server that a specific compression type is desired, but the server is not required to honor the hint in the corresponding response. More than one compression protocol AVP MAY be sent. It is the responsibility of the NAS to apply the proper compression protocol to appropriate link traffic. The supported values are listed in [33]. 7.2.5 IP Access The AVPs defined in this section are used when the user requests, or is being granted, access to IP. They are only present if the Framed- Protocol AVP (see Section 7.2.1) is set to PPP, SLIP, Gandalf proprietarySingleLink/MultiLink protocol, or X.75 Synchronous. 7.2.5.1 Framed-IP-Address AVP The Framed-IP-Address AVP (AVP Code 8) is of type IPAddress and contains the address to be configured for the user. It MAY be used in an authorization request as a hint to the server that a specific address is desired, but the server is not required to honor the hint in the corresponding response. Calhoun et al. expires September 2002 [Page 31]
Internet-Draft Diameter NASREQ Application March 2002 Two addresses have special significance; 0xFFFFFFFF and 0xFFFFFFFE. The value 0xFFFFFFFF indicates that the NAS should allow the user to select an address (e.g. Negotiated). The value 0xFFFFFFFE indicates that the NAS should select an address for the user (e.g. Assigned from a pool of addresses kept by the NAS). 7.2.5.2 Framed-IP-Netmask AVP The Framed-IP-Netmask AVP (AVP Code 9) is of type IPAddress and contains the IP netmask to be configured for the user when the user is a router to a network. It MAY be used in an authorization request as a hint to the server that a specific netmask is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST be present in a response if the request included this AVP with a value of 0xFFFFFFFF. 7.2.5.3 Framed-IP-Route AVP The Framed-IP-Route AVP (AVP Code 22) is of type UTF8String, and contains the routing information to be configured for the user on the NAS. Zero or more such AVPs MAY be present in an authorization response. The string MUST contain a destination prefix in dotted quad form optionally followed by a slash and a decimal length specifier stating how many high order bits of the prefix should be used. That is followed by a space, a gateway address in dotted quad form, a space, and one or more metrics separated by spaces. For example, "192.168.1.0/24 192.168.1.1 1". The length specifier may be omitted in which case it should default to 8 bits for class A prefixes, 16 bits for class B prefixes, and 24 bits for class C prefixes. For example, "192.168.1.0 192.168.1.1 1". Whenever the gateway address is specified as "0.0.0.0" the IP address of the user SHOULD be used as the gateway address. 7.2.5.4 Framed-Interface-Id AVP The Framed-Interface-Id AVP (AVP Code 96) is of type Unsigned64 and contains the IPv6 interface identifier to be configured for the user. It MAY be used in authorization requests as a hint to the server that a specific interface id is desired, but the server is not required to honor the hint in the corresponding response. Calhoun et al. expires September 2002 [Page 32]
Internet-Draft Diameter NASREQ Application March 2002 7.2.5.5 Framed-IPv6-Prefix AVP The Framed-IPv6-Prefix AVP (AVP Code 97) is of type IPAddress and contains the IPv6 prefix to be configured for the user. One or more AVPs MAY be used in authorization requests as a hint to the server that a specific IPv6 prefixes are desired, but the server is not required to honor the hint in the corresponding response. 7.2.5.6 Framed-IPv6-Route AVP The Framed-IPv6-Route AVP (AVP Code 99) is of type UTF8String, and contains the routing information to be configured for the user on the NAS. Zero or more such AVPs MAY be present in an authorization response. The string MUST contain an IPv6 address prefix followed by a slash and a decimal length specifier stating how many high order bits of the prefix should be used. That is followed by a space, a gateway address in hexadecimal notation, a space, and one or more metrics separated by spaces. For example: "2000:0:0:106::/64 2000::106:a00:20ff:fe99:a998 1". Whenever the gateway address is the IPv6 unspecified address the IP address of the user SHOULD be used as the gateway address, such as: "2000:0:0:106::/64 :: 1". 7.2.5.7 Framed-IPv6-Pool AVP The Framed-IPv6-Pool AVP (AVP Code 100) is of type UTF8String, and contains the name of an assigned pool that SHOULD be used to assign an IPv6 prefix for the user. If the access device does not support multiple prefix pools, it MUST ignore this AVP. 7.2.6 IPX Access The AVPs defined in this section are used when the user requests, or is being granted, access to IPX. They are only present if the Framed- Protocol AVP (see Section 7.2.1) is set to PPP, Xylogics proprietary IPX/SLIP, Gandalf proprietarySingleLink/MultiLink protocol, or X.75 Synchronous. 7.2.6.1 Framed-IPX-Network AVP The Framed-IPX-Network AVP (AVP Code 23) is of type UTF8String, and Calhoun et al. expires September 2002 [Page 33]
Internet-Draft Diameter NASREQ Application March 2002 contains the IPX Network number to be configured for the user. It MAY be used in an authorization request as a hint to the server that a specific address is desired, but the server is not required to honor the hint in the corresponding response. Two addresses have special significance; 0xFFFFFFFF and 0xFFFFFFFE. The value 0xFFFFFFFF indicates that the NAS should allow the user to select an address (e.g. Negotiated). The value 0xFFFFFFFE indicates that the NAS should select an address for the user (e.g. assigned from a pool of one or more IPX networks kept by the NAS). 7.2.7 Appletalk Access The AVPs defined in this section are used when the user requests, or is being granted, access to Appletalk. They are only present if the Framed-Protocol AVP (see Section 7.2.1) is set to PPP, Gandalf proprietary SingleLink/MultiLink protocol, or X.75 Synchronous. 7.2.7.1 Framed-AppleTalk-Link AVP The Framed-AppleTalk-Link AVP (AVP Code 37) is of type Unsigned32 and contains the AppleTalk network number which should be used for the serial link to the user, which is another AppleTalk router. This AVP MUST only be present in an authorization response and is never used when the user is not another router. Despite the size of the field, values range from zero to 65535. The special value of zero indicates that this is an unnumbered serial link. A value of one to 65535 means that the serial line between the NAS and the user should be assigned that value as an AppleTalk network number. 7.2.7.2 Framed-AppleTalk-Network AVP The Framed-AppleTalk-Network AVP (AVP Code 38) is of type Unsigned32 and contains the AppleTalk Network number which the NAS should probe to allocate an AppleTalk node for the user. This AVP MUST only be present in an authorization response and is never used when the user is not another router. Multiple instances of this AVP indicate that the NAS may probe using any of the network numbers specified. Despite the size of the field, values range from zero to 65535. The special value zero indicates that the NAS should assign a network for the user, using its default cable range. A value between one and 65535 (inclusive) indicates the AppleTalk Network the NAS should Calhoun et al. expires September 2002 [Page 34]
Internet-Draft Diameter NASREQ Application March 2002 probe to find an address for the user. 7.2.7.3 Framed-AppleTalk-Zone AVP The Framed-AppleTalk-Zone AVP (AVP Code 39) is of type OctetString and contains the AppleTalk Default Zone to be used for this user. This AVP MUST only be present in an authorization response. Multiple instances of this AVP in the same message are not allowed. The codification of the range of allowed usage of this field is outside the scope of this specification. 7.2.8 ARAP Access The AVPs defined in this section are used when the user requests, or is being granted, access to ARAP. They are only present if the Framed-Protocol AVP (see Section 7.2.1) is set to AppleTalk Remote Access Protocol (ARAP). 7.2.8.1 ARAP-Features AVP The ARAP-Features AVP (AVP Code 71) is of type OctetString, and MAY be present in the AA-Accept message if the Framed-Protocol AVP is set to the value of ARAP. See [32] for more information of the format of this AVP. 7.2.8.2 ARAP-Zone-Access AVP The ARAP-Zone-Access AVP (AVP Code 72) is of type Enumerated, and MAY be present in the AA-Accept message if the Framed-Protocol AVP is set to the value of ARAP. The supported values are listed in [33], and are defined in [32]. 7.2.8.3 ARAP-Security AVP The ARAP-Security AVP (AVP Code 73) is of type Unsigned32, and MAY be present in the AA-Answer message if the Framed-Protocol AVP is set to the value of ARAP, and the Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH. See [32] for more information of the format of this AVP. Calhoun et al. expires September 2002 [Page 35]
Internet-Draft Diameter NASREQ Application March 2002 7.2.8.4 ARAP-Security-Data AVP The ARAP-Security AVP (AVP Code 74) is of type OctetString, and MAY be present in the AA-Request or AA-Answer message if the Framed- Protocol AVP is set to the value of ARAP, and the Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH. This AVP contains the security module challenge or response associated with the ARAP Security Module specified in ARAP-Security. 7.3 Non-Framed Access Authorization AVPs This section contains the authorization AVPs that are needed to support terminal server functionality. AVPs defined in this section MAY be present in a message if the Service-Type AVP was set to "Login" or "Callback Login". 7.3.1 Login-IP-Host AVP The Login-IP-Host AVP (AVP Code 14) is of type IPAddress and contains the system with which to connect the user, when the Login-Service AVP is included. It MAY be used in an authorization request as a hint to the server that a specific host is desired, but the server is not required to honor the hint in the corresponding response. Two addresses have special significance; 0xFFFFFFFF and 0xFFFFFFFE. The value 0xFFFFFFFF indicates that the NAS SHOULD allow the user to select an address. The value zero indicates that the NAS SHOULD select a host to connect the user to. 7.3.2 Login-Service AVP The Login-Service AVP (AVP Code 15) is of type Enumerated and contains the service which should be used to connect the user to the login host. This AVP SHOULD only be present in authorization responses. The supported values are listed in [33]. 7.3.3 TCP Services The AVP described in this section MAY be present if the Login-Service AVP is set to Telnet, Rlogin, TCP Clear or TCP Clear Quiet. Calhoun et al. expires September 2002 [Page 36]
Internet-Draft Diameter NASREQ Application March 2002 7.3.3.1 Login-TCP-Port AVP The Login-TCP-Port AVP (AVP Code 16) is of type Unsigned32 and contains the TCP port with which the user is to be connected, when the Login-Service AVP is also present. This AVP SHOULD only be present in authorization responses. The value MUST NOT be greater than 65535. 7.3.4 LAT Services The AVP described in this section MAY be present if the Login-Service AVP is set to LAT. 7.3.4.1 Login-LAT-Service AVP The Login-LAT-Service AVP (AVP Code 34) is of type OctetString and contains the system with which the user is to be connected by LAT. It MAY be used in an authorization request as a hint to the server that a specific service is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST only be present in the response if the Login-Service AVP states that LAT is desired. Administrators use the service attribute when dealing with clustered systems, such as a VAX or Alpha cluster. In such an environment several different time sharing hosts share the same resources (disks, printers, etc.), and administrators often configure each to offer access (service) to each of the shared resources. In this case, each host in the cluster advertises its services through LAT broadcasts. Sophisticated users often know which service providers (machines) are faster and tend to use a node name when initiating a LAT connection. Alternately, some administrators want particular users to use certain machines as a primitive form of load balancing (although LAT knows how to do load balancing itself). The String field contains the identity of the LAT service to use. The LAT Architecture allows this string to contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper and lower case alphabetics, and the ISO Latin-1 character set extension [8]. All LAT string comparisons are case insensitive. 7.3.4.2 Login-LAT-Node AVP The Login-LAT-Node AVP (AVP Code 35) is of type OctetString and Calhoun et al. expires September 2002 [Page 37]
Internet-Draft Diameter NASREQ Application March 2002 contains the Node with which the user is to be automatically connected by LAT. It MAY be used in an authorization request as a hint to the server that a specific LAT node is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST only be present in a response if the Service- Type AVP is set to LAT. The String field contains the identity of the LAT service to use. The LAT Architecture allows this string to contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper and lower case alphabetics, and the ISO Latin-1 character set extension [8]. All LAT string comparisons are case insensitive. 7.3.4.3 Login-LAT-Group AVP The Login-LAT-Group AVP (AVP Code 36) is of type OctetString and contains a string identifying the LAT group codes which this user is authorized to use. It MAY be used in an authorization request as a hint to the server that a specific group is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST only be present in a response if the Service-Type AVP is set to LAT. LAT supports 256 different group codes, which LAT uses as a form of access rights. LAT encodes the group codes as a 256 bit bitmap. Administrators can assign one or more of the group code bits at the LAT service provider; it will only accept LAT connections that have these group codes set in the bit map. The administrators assign a bitmap of authorized group codes to each user; LAT gets these from the operating system, and uses these in its requests to the service providers. The codification of the range of allowed usage of this field is outside the scope of this specification. 7.3.4.4 Login-LAT-Port AVP The Login-LAT-Port AVP (AVP Code 63) is of type OctetString and contains the Port with which the user is to be connected by LAT. It MAY be used in an authorization request as a hint to the server that a specific port is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST only be present in a response if the Service-Type AVP is set to LAT. The String field contains the identity of the LAT service to use. Calhoun et al. expires September 2002 [Page 38]
Internet-Draft Diameter NASREQ Application March 2002 The LAT Architecture allows this string to contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper and lower case alphabetics, and the ISO Latin-1 character set extension [8]. All LAT string comparisons are case insensitive. 7.4 Tunneling AVPs | The Tunneling AVP (AVP Code 403) is of type Grouped and contains AVPs used to describe a tunnel. Its Data field has the following ABNF grammar: Tunneling ::= < AVP Header: 403 > { Tunnel-Type } { Tunnel-Medium-Type } { Tunnel-Client-Endpoint } { Tunnel-Server-Endpoint } [ Tunnel-Preference ] [ Tunnel-Client-Auth-ID ] [ Tunnel-Server-Auth-ID ] [ Tunnel-Assignment-ID ] [ Tunnel-Password ] [ Tunnel-Private-Group-ID ] 7.4.1 Tunnel-Type AVP The Tunnel-Type AVP (AVP Code 64) is of type Enumerated and contains the tunneling protocol(s) to be used (in the case of a tunnel initiator) or the tunneling protocol in use (in the case of a tunnel terminator). It MAY be used in an authorization request as a hint to the server that a specific tunnel type is desired, but the server is not required to honor the hint in the corresponding response. The Tunnel-Type AVP SHOULD also be included in Accounting-Request | messages. A tunnel initiator is not required to implement any of these tunnel types; if a tunnel initiator receives a response that contains only unknown or unsupported Tunnel-Types, the tunnel initiator MUST behave as though a response was received with the Result-Code indicating a failure. The supported values are listed in [33]. 7.4.2 Tunnel-Medium-Type AVP Calhoun et al. expires September 2002 [Page 39]
Internet-Draft Diameter NASREQ Application March 2002 The Tunnel-Medium-Type AVP (AVP Code 65) is of type Enumerated and contains the transport medium to use when creating a tunnel for those protocols (such as L2TP) that can operate over multiple transports. It MAY be used in an authorization request as a hint to the server that a specific medium is desired, but the server is not required to honor the hint in the corresponding response. The Value field contains one of the values listed under "Address Family Numbers" in [10]. The value of most importance is (1) for IPv4 and (2) for IPv6. 7.4.3 Tunnel-Client-Endpoint AVP The Tunnel-Client-Endpoint AVP (AVP Code 66) is of type UTF8String, and contains the address of the initiator end of the tunnel. It MAY be used in an authorization request as a hint to the server that a specific endpoint is desired, but the server is not required to honor the hint in the corresponding response. This AVP SHOULD be included in the corresponding Accounting-Request | messages, in which case it indicates the address from which the tunnel was initiated. This AVP, along with the Tunnel-Server-Endpoint and Session-Id AVP [2], MAY be used to provide a globally unique means to identify a tunnel for accounting and auditing purposes. If Tunnel-Medium-Type is IPv4 (1), then this string is either the fully qualified domain name (FQDN) of the tunnel client machine, or it is a "dotted-decimal" IP address. Conformant implementations MUST support the dotted-decimal format and SHOULD support the FQDN format for IP addresses. If Tunnel-Medium-Type is IPv6 (2), then this string is either the FQDN of the tunnel client machine, or it is a text representation of the address in either the preferred or alternate form [5]. Conformant implementations MUST support the preferred form and SHOULD support both the alternate text form and the FQDN format for IPv6 addresses. If Tunnel-Medium-Type is neither IPv4 nor IPv6, this string is a tag referring to configuration data local to the Diameter client that describes the interface and medium-specific address to use. 7.4.4 Tunnel-Server-Endpoint AVP The Tunnel-Server-Endpoint AVP (AVP Code 67) is of UTF8String, and contains the address of the server end of the tunnel. It MAY be used Calhoun et al. expires September 2002 [Page 40]
Internet-Draft Diameter NASREQ Application March 2002 in an authorization request as a hint to the server that a specific endpoint is desired, but the server is not required to honor the hint in the corresponding response. This AVP SHOULD be included in the corresponding Accounting-Request | messages, in which case it indicates the address from which the tunnel was initiated. This AVP, along with the Tunnel-Client-Endpoint and Session-Id AVP [2], MAY be used to provide a globally unique means to identify a tunnel for accounting and auditing purposes. If Tunnel-Medium-Type is IPv4 (1), then this string is either the fully qualified domain name (FQDN) of the tunnel client machine, or it is a "dotted-decimal" IP address. Conformant implementations MUST support the dotted-decimal format and SHOULD support the FQDN format for IP addresses. If Tunnel-Medium-Type is IPv6 (2), then this string is either the FQDN of the tunnel client machine, or it is a text representation of the address in either the preferred or alternate form [5]. Conformant implementations MUST support the preferred form and SHOULD support both the alternate text form and the FQDN format for IPv6 addresses. If Tunnel-Medium-Type is not IPv4 or IPv6, this string is a tag referring to configuration data local to the Diameter client that describes the interface and medium-specific address to use. 7.4.5 Tunnel-Password AVP The Tunnel-Password AVP (AVP Code 69) is of type OctetString and may contain a password to be used to authenticate to a remote server. This AVP MUST only be present in authorization responses in an encrypted form, using one of the methods described in [2] and [13]. 7.4.6 Tunnel-Private-Group-ID AVP The Tunnel-Private-Group-ID AVP (AVP Code 81) is of type UTF8String, and contains the group ID for a particular tunneled session. The Tunnel-Private-Group-ID AVP MAY be included in an authorization request if the tunnel initiator can pre-determine the group resulting from a particular connection and SHOULD be included in the authorization response if this tunnel session is to be treated as belonging to a particular private group. Private groups may be used to associate a tunneled session with a particular group of users. For example, it MAY be used to facilitate routing of unregistered IP addresses through a particular interface. This AVP SHOULD be | Calhoun et al. expires September 2002 [Page 41]
Internet-Draft Diameter NASREQ Application March 2002 included in the Accounting-Request messages which pertain to the | tunneled session. 7.4.7 Tunnel-Assignment-ID AVP The Tunnel-Assignment-ID AVP (AVP Code 82) is of type OctetString and is used to indicate to the tunnel initiator the particular tunnel to which a session is to be assigned. Some tunneling protocols, such as PPTP [14] and L2TP, allow for sessions between the same two tunnel endpoints to be multiplexed over the same tunnel and also for a given session to utilize its own dedicated tunnel. This attribute provides a mechanism for Diameter to be used to inform the tunnel initiator (e.g. PAC, LAC) whether to assign the session to a multiplexed tunnel or to a separate tunnel. Furthermore, it allows for sessions sharing multiplexed tunnels to be assigned to different multiplexed tunnels. A particular tunneling implementation may assign differing characteristics to particular tunnels. For example, different tunnels may be assigned different QOS parameters. Such tunnels may be used to carry either individual or multiple sessions. The Tunnel- Assignment-ID attribute thus allows the Diameter server to indicate that a particular session is to be assigned to a tunnel that provides an appropriate level of service. It is expected that any QOS-related Diameter tunneling attributes defined in the future that accompany this attribute will be associated by the tunnel initiator with the ID given by this attribute. In the meantime, any semantic given to a particular ID string is a matter left to local configuration in the tunnel initiator. The Tunnel-Assignment-ID AVP is of significance only to Diameter and the tunnel initiator. The ID it specifies is intended to be of only local use to Diameter and the tunnel initiator. The ID assigned by the tunnel initiator is not conveyed to the tunnel peer. This attribute MAY be included in authorization responses. The tunnel initiator receiving this attribute MAY choose to ignore it and assign the session to an arbitrary multiplexed or non-multiplexed tunnel | between the desired endpoints. This AVP SHOULD also be included in | the Accounting-Request messages which pertain to the tunneled | session. If a tunnel initiator supports the Tunnel-Assignment-ID AVP, then it should assign a session to a tunnel in the following manner: - If this AVP is present and a tunnel exists between the specified endpoints with the specified ID, then the session should be Calhoun et al. expires September 2002 [Page 42]
Internet-Draft Diameter NASREQ Application March 2002 assigned to that tunnel. - If this AVP is present and no tunnel exists between the specified endpoints with the specified ID, then a new tunnel should be established for the session and the specified ID should be associated with the new tunnel. - If this AVP is not present, then the session is assigned to an unnamed tunnel. If an unnamed tunnel does not yet exist between the specified endpoints then it is established and used for this and subsequent sessions established without the Tunnel- Assignment-ID attribute. A tunnel initiator MUST NOT assign a session for which a Tunnel-Assignment-ID AVP was not specified to a named tunnel (i.e. one that was initiated by a session specifying this AVP). Note that the same ID may be used to name different tunnels if such tunnels are between different endpoints. 7.4.8 Tunnel-Preference AVP The Tunnel-Preference AVP (AVP Code 83) is of type Unsigned32 and is used to identify the relative preference assigned to each tunnel when more than one set of tunneling AVPs is returned within separate Grouped-AVP AVPs. It MAY be used in an authorization request as a hint to the server that a specific preference is desired, but the server is not required to honor the hint in the corresponding response. For example, suppose that AVPs describing two tunnels are returned by the server, one with a Tunnel-Type of PPTP and the other with a Tunnel-Type of L2TP. If the tunnel initiator supports only one of the Tunnel-Types returned, it will initiate a tunnel of that type. If, however, it supports both tunnel protocols, it SHOULD use the value of the Tunnel-Preference AVP to decide which tunnel should be started. The tunnel having the numerically lowest value in the Value field of this AVP SHOULD be given the highest preference. The values assigned to two or more instances of the Tunnel-Preference AVP within a given authorization response MAY be identical. In this case, the tunnel initiator SHOULD use locally configured metrics to decide which set of AVPs to use. 7.4.9 Tunnel-Client-Auth-ID AVP The Tunnel-Client-Auth-ID AVP (AVP Code 90) is of type Unsigned32 and specifies the name used by the tunnel initiator during the Calhoun et al. expires September 2002 [Page 43]
Internet-Draft Diameter NASREQ Application March 2002 authentication phase of tunnel establishment. It MAY be used in an authorization request as a hint to the server that a specific preference is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST be present in the authorization response if an authentication name other than the default is desired. This AVP SHOULD be included in the Accounting- | Request messages which pertain to the tunneled session. 7.4.10 Tunnel-Server-Auth-ID AVP The Tunnel-Server-Auth-ID AVP (AVP Code 91) is of type OctetString and specifies the name used by the tunnel terminator during the authentication phase of tunnel establishment. It MAY be used in an authorization request as a hint to the server that a specific preference is desired, but the server is not required to honor the hint in the corresponding response. This AVP MUST be present in the authorization response if an authentication name other than the default is desired. This AVP SHOULD be included in the the | Accounting-Request messages which pertain to the tunneled session. 8.0 Accounting AVPs This section contains a description of the AVPs defined in this document that are to be included in Diameter accounting messages [2]. 8.1 Accounting-Input--Octets AVP | The Accounting-Input-Octets AVP (AVP Code 363) is of type Unsigned64, | and contains the number of octets received from the user. | For NASREQ usage, this AVP indicates how many octets have been | received from the port in the course of this session and can only be | present in ACR messages with an Accounting-Record-Type of | INTERIM_RECORD or STOP_RECORD. 8.2 Accounting-Output-Octets AVP | The Accounting-Output-Octets AVP (AVP Code 364) is of type | Unsigned64, and contains the number of octets sent to the user. | For NASREQ usage, this AVP indicates how many octets have been sent | to the port in the course of this session and can only be present in | ACR messages with an Accounting-Record-Type of INTERIM_RECORD or | STOP_RECORD. Calhoun et al. expires September 2002 [Page 44]
Internet-Draft Diameter NASREQ Application March 2002 8.3 Acct-Session-Time AVP | The Acct-Session-Time AVP (AVP Code 46) is of type Unsigned32, and | indicates the length of the current session in seconds. It can only | be present in ACR messages with an Accounting-Record-Type of | INTERIM_RECORD or STOP_RECORD. 8.4 Accounting-Input-Packets AVP | The Accounting-Input-Packets (AVP Code 365) is of type Unsigned64, | and contains the number of packets received from the user. | For NASREQ usage, this AVP indicates how many packets have been | received from the port over the course of a session being provided to | a Framed User and can only be present in ACR messages with an | Accounting-Record-Type of INTERIM_RECORD or STOP_RECORD. 8.5 Accounting-Output-Packets AVP | The Accounting-Output-Packets (AVP Code 366) is of type Unsigned64, | and contains the number of IP packets sent to the user. | For NASREQ usage, this AVP indicates how many packets have been sent | to the port over the course of a session being provided to a Framed | User and can only be present in ACR messages with an Accounting- | Record-Type of INTERIM_RECORD or STOP_RECORD. 8.6 Accounting-Authentication-Type AVP The Accounting-Authentication-Type AVP (AVP Code 45) is of type Unsigned32, and specifies how the user was authenticated. The supported values are listed in [33]. 8.7 Acct-Tunnel-Connection AVP The Acct-Tunnel-Connection AVP (AVP Code 68) is of type OctetString, and contains the identifier assigned to the tunnel session. This AVP, along with the Tunnel-Client-Endpoint and Tunnel-Server-Endpoint AVPs, may be used to provide a means to uniquely identify a tunnel session for auditing purposes. The format of the identifier in this AVP depends upon the value of the Tunnel-Type AVP. For example, to fully identify an L2TP tunnel connection, the L2TP Tunnel ID and Call ID might be encoded in this Calhoun et al. expires September 2002 [Page 45]
Internet-Draft Diameter NASREQ Application March 2002 field. The exact encoding of this field is implementation dependent. 8.8 Acct-Tunnel-Packets-Lost AVP The Acct-Tunnel-Packets-Lost AVP (AVP Code 86) is of type Unsigned32 and contains the number of packets lost on a given link. 8.9 Accounting-EAP-Auth-Method AVP This Accounting-EAP-Auth-Method AVP (AVP Code 401) is of type Enumerated, and uses the EAP Type name space defined in [25]. 9.0 RADIUS/Diameter Protocol Interactions This section describes some basic guidelines that may be used by servers that act as protocol gateways. Note that this document does not restrict implementations from creating other methods, as long as the bridging function doesn't break the RADIUS nor the Diameter protocol. There are essentially two different situations that must be handled; one where a RADIUS request is received that must be forwarded as a Diameter request, and the inverse. Note that this section uses two different terms; AVP and attribute. The former is used to signify a Diameter AVP, while the latter is used to signify a RADIUS attribute. 9.1 RADIUS request forwarded as Diameter request This section describes the actions that should be followed when a protocol Gateway receives a RADIUS message that is to be translated to a Diameter message. It is important to note that RADIUS servers are inherently stateless, and this section maintains that assumption. It is quite possible for the RADIUS messages that comprises the session (i.e. authentication and accounting messages) be handled by different protocol gateways in the proxy network. Therefore a RADIUS->Diameter protocol gateway cannot maintain session state information. When a protocol gateway receives a RADIUS message, the following steps should be taken: - If the NAS-IP-Address attribute is present in the RADIUS message, the name MUST be translated to its corresponding FQDN, Calhoun et al. expires September 2002 [Page 46]
Internet-Draft Diameter NASREQ Application March 2002 and encoded in the Diameter message's Origin-Host AVP. If the NAS-Identifier attribute is present, the data can be used in the Origin-Host AVP. - The Origin-Host AVP is added with the local server's identity. This will ensure that the corresponding response will be returned to the correct gateway server. The aaa protocol specified in the identity would be set to "radius". - The Destination-Realm AVP is created from the information found in the RADIUS User-Name attribute. - If the RADIUS CHAP-Password attribute is present, the Ident and Data portion of the attribute are used to create the CHAP-Auth Grouped AVP. - The Gateway Server must maintain state information relevant to the RADIUS request, such as the Identifier field in the RADIUS header, any existing RADIUS Proxy-State attribute as well as the source IP address and port number of the UDP packet. These may be maintained locally in a state table, or may be saved in a Proxy-Info AVP. - If the Acct-Session-Id attribute was found in the request, the contents are inserted in the Acct-Session-Id AVP. - If the RADIUS request contained a State attribute, and the prefix of the data is "Diameter/", the data following the prefix contains the Diameter Session-Id. If no such attributes are present, and the RADIUS command is an Access-Request, a new Session-Id is created. The Session-Id is included in the Session-Id AVP. - If the RADIUS message received is an Accounting-Request, with the Acct-Status-Type attribute set to STOP, the local server MUST issue a Session-Termination-Request message once the Diameter Accounting-Answer has been received. - If the RADIUS message contains the Accounting-Input-Octets, Accounting-Input-Packets, Accounting-Output-Octets or Accounting-Output-Packets, these attributes must be converted to the Diameter equivalent ones. Further, if the Acct-Input- Gigawords or Acct-Output-Gigawords attributes are present, these must be used to properly compute the Diameter accounting AVPs. The corresponding Diameter response is always guaranteed to be received by the same protocol gateway that translated the original request, due to the contents of the Origin-Host AVP in the Diameter request. The following steps are applied to the response message during the Diameter to RADIUS translation: - If the Diameter Command-Code is set to AA-Answer and the Result- Code AVP is set to DIAMETER_MULTI_ROUND_AUTH, the gateway must send a RADIUS Access-Challenge with the Diameter Session-Id and the Origin-Host AVPs encapsulated in the RADIUS State attribute, with the prefix "Diameter/". This is necessary in order to Calhoun et al. expires September 2002 [Page 47]
Internet-Draft Diameter NASREQ Application March 2002 ensure that the protocol gateway that will receive the subsequent RADIUS Access-Request will have access to the Session Identifier, and be able to set the Destination-Host to the correct value. If the Multi-Round-Time-Out AVP is present, the value of the AVP MUST be inserted in the RADIUS Session-Timeout AVP. - If the Command-Code is set to AA-Answer, the Diameter Session-Id AVP is saved in a new RADIUS Class attribute, whose format consists of the string "Diameter/" followed by the Diameter Session Identifier. This will ensure that the subsequent Accounting messages, which could be received by any protocol gateway, would have access to the original Diameter Session Identifier. - If a Proxy-State attribute was present in the RADIUS request, the same attribute is added in the response. This information may be found in the Proxy-Info AVP, or in a local state table. - If state information regarding the RADIUS request was saved in a Proxy-Info AVP, the RADIUS Identifier and UDP IP Address and port number are extracted and used in issuing the RADIUS reply. 9.2 Diameter request forwarded as RADIUS request When a server receives a Diameter request that is to be forwarded to a RADIUS entity, the following steps are an example of the steps that may be followed: - The Origin-Host AVP's value is inserted in the NAS-Identifier attribute. - The following information MUST be present in the corresponding Diameter response, and therefore MUST be saved either in a local state table, or it MAY be encoded in a RADIUS Proxy-State attribute: 1. Origin-Host AVP 2. Session-Id AVP 3. Proxy-Info AVP 4. Route-Record AVPs (in the proper order) 5. Any other AVP that MUST be present in the response, and has no corresponding RADIUS attribute. - If the CHAP-Auth AVP is present, the Grouped AVPs are used to create the RADIUS CHAP-Password. | - If the Accounting-Input-Octets, Accounting-Input-Packets, | Accounting-Output-Octets or Accounting-Output-Packets AVPs are present, these must be translated to the corresponding RADIUS attributes. Further, the the Diameter AVPs do not fit within a 32-bit RADIUS attribute, the RADIUS Acct- Input-Gigawords and Acct-Output-Gigawords must be used. Calhoun et al. expires September 2002 [Page 48]
Internet-Draft Diameter NASREQ Application March 2002 When the corresponding response is received by the gateway server, which is guaranteed in the RADIUS protocol, the following steps may be followed: - If the RADIUS code is set to Access-Challenge, a Diameter AA- Answer message is created with the Result-Code set to DIAMETER_MULTI_ROUND_AUTH. If the Session-Timeout AVP is present in the RADIUS message, its value is inserted in the Multi-Round- Time-Out AVP. - If a Proxy-Info AVP is present, extract the encoded information, otherwise retrieve the information from the local state table. - The request's Origin-Host information is added to the Destination-Host AVP. - The Session-Id information is added to the Session-Id AVP. - The Route-Record AVPs MUST be added to the Diameter message, in the same order they were present in the request. - If a Proxy-Info AVP was present in the request, the same AVP MUST be added to the response. - If the RADIUS State attributes are present, these attributes must be present in the Diameter response. - Any other AVPs that were saved, and MUST be present in the response, are added to the message. 10.0 AVP Occurrence Table The following tables presents the AVPs defined in this document, and specifies in which Diameter messages they MAY, or MAY NOT be present. Note that AVPs that can only be present within a Grouped AVP are not represented in this table. The table uses the following symbols: 0 The AVP MUST NOT be present in the message. 0+ Zero or more instances of the AVP MAY be present in the message. 0-1 Zero or one instance of the AVP MAY be present in the message. 1 One instance of the AVP MUST be present in the message. 10.1 NASREQ Command AVP Table The table in this section is limited to the Command Codes defined in this specification. Calhoun et al. expires September 2002 [Page 49]
Internet-Draft Diameter NASREQ Application March 2002 +-----------------------+ | Command-Code | |-----+-----+-----+-----+ Attribute Name | AAR | AAA | DER | DEA | ------------------------------|-----+-----+-----+-----| ARAP-Challenge-Response | 0 | 0-1 | 0 | 0 | | ARAP-Features | 0 | 0-1 | 0 | 0 | | ARAP-Password | 0-1 | 0 | 0 | 0 | ARAP-Security | 0-1 | 0-1 | 0 | 0 | | ARAP-Security-Data | 0+ | 0+ | 0 | 0 | | ARAP-Zone-Access | 0 | 0-1 | 0 | 0 | | Auth-Application-Id | 1 | 1 | 1 | 1 | Auth-Grace-Period | 0-1 | 0-1 | 0-1 | 0-1 | Auth-Request-Type | 1 | 1 | 1 | 1 | | Auth-Session-State | 0-1 | 0-1 | 0-1 | 0-1 | Authorization-Lifetime | 0-1 | 0-1 | 0-1 | 0-1 | Callback-Id | 0 | 0-1 | 0 | 0-1 | Callback-Number | 0-1 | 0-1 | 0-1 | 0-1 | Called-Station-Id | 0-1 | 0 | 0-1 | 0 | Calling-Station-Id | 0-1 | 0 | 0-1 | 0 | CHAP-Auth | 0-1 | 0 | 0 | 0 | CHAP-Challenge | 0-1 | 0 | 0 | 0 | Connect-Info | 0-1 | 0 | 0-1 | 0 | Destination-Host | 0-1 | 0 | 0-1 | 0 | | Destination-Realm | 1 | 0 | 1 | 0 | EAP-Payload | 0 | 0 | 1 | 0-1 | | Error-Message | 0 | 0-1 | 0 | 0-1 | Error-Reporting-Host | 0 | 0-1 | 0 | 0+ | Filter-Id | 0 | 0+ | 0 | 0+ | Framed-Appletalk-Link | 0 | 0-1 | 0 | 0-1 | Framed-Appletalk-Network | 0 | 0+ | 0 | 0+ | Framed-Appletalk-Zone | 0 | 0-1 | 0 | 0-1 | Framed-Compression | 0+ | 0+ | 0+ | 0+ | Framed-Interface-Id | 0-1 | 0-1 | 0-1 | 0-1 | Framed-IP-Address | 0-1 | 0-1 | 0-1 | 0-1 | Framed-IP-Netmask | 0-1 | 0-1 | 0-1 | 0-1 | Framed-IP-Route | 0 | 0+ | 0 | 0+ | Framed-IPv6-Prefix | 0+ | 0+ | 0+ | 0+ | Framed-IPv6-Pool | 0 | 0-1 | 0 | 0-1 | | Framed-IPv6-Route | 0 | 0+ | 0 | 0+ | | Framed-IPX-Network | 0 | 0-1 | 0 | 0-1 | Framed-MTU | 0-1 | 0-1 | 0-1 | 0-1 | | Framed-Protocol | 0-1 | 0-1 | 0-1 | 0-1 | | Framed-Routing | 0 | 0-1 | 0 | 0-1 | | Idle-Timeout | 0-1 | 0-1 | 0-1 | 0-1 | Login-IP-Host | 0+ | 0+ | 0 | 0 | Login-LAT-Group | 0-1 | 0-1 | 0 | 0 | Login-LAT-Node | 0-1 | 0-1 | 0 | 0 | Calhoun et al. expires September 2002 [Page 50]
Internet-Draft Diameter NASREQ Application March 2002 +-----------------------+ | Command-Code | |-----+-----+-----+-----+ Attribute Name | AAR | AAA | DER | DEA | ------------------------------|-----+-----+-----+-----| Login-LAT-Port | 0-1 | 0-1 | 0 | 0 | Login-LAT-Service | 0-1 | 0-1 | 0 | 0 | Login-Service | 0 | 0-1 | 0 | 0 | | Login-TCP-Port | 0 | 0-1 | 0 | 0 | | NAS-Filter-Rule | 0 | 0+ | 0 | 0+ | NAS-Identifier | 0-1 | 0 | 0-1 | 0 | | NAS-IP-Address | 0-1 | 0 | 0-1 | 0 | | NAS-Key-Binding | 0-1 | 0 | 0-1 | 0 | NAS-Port | 0-1 | 0 | 0-1 | 0 | | NAS-Port-Type | 0-1 | 0 | 0-1 | 0 | NAS-Session-Key | 0 | 0+ | 0 | 0+ | Origin-Host | 1 | 1 | 1 | 1 | Origin-Realm | 1 | 1 | 1 | 1 | Origin-State-Id | 0-1 | 0-1 | 0-1 | 0-1 | Password-Retry | 0 | 0-1 | 0 | 0 | Port-Limit | 0-1 | 0-1 | 0-1 | 0-1 | | Prompt | 0 | 0-1 | 0 | 0 | Proxy-Info | 0+ | 0+ | 0+ | 0+ | Redirect-Host | 0 | 0+ | 0 | 0+ | Redirect-Host-Usage | 0 | 0-1 | 0 | 0-1 | Redirect-Max-Cache-Time | 0 | 0-1 | 0 | 0-1 | Reply-Message | 0 | 0+ | 0 | 0 | | Result-Code | 0 | 1 | 0 | 1 | Re-Auth-Request-Type | 0 | 0-1 | 0 | 0-1 | Route-Record | 0+ | 0 | 0+ | 0 | Service-Type | 0-1 | 0-1 | 0-1 | 0-1 | | Session-Id | 1 | 1 | 1 | 1 | Session-Timeout | 0-1 | 0-1 | 0-1 | 0-1 | | State | 0-1 | 0-1 | 0-1 | 0-1 | | Tunneling | 0+ | 0+ | 0+ | 0+ | User-Name | 0-1 | 0-1 | 0-1 | 0-1 | User-Password | 0-1 | 0 | 0 | 0 | 10.2 Accounting AVP Table The tables in this section are used to represent which AVPs defined in this document are to be present in the Accounting messages, defined in [1]. 10.2.1 Framed Access Calhoun et al. expires September 2002 [Page 51]
Internet-Draft Diameter NASREQ Application March 2002 The table in this section is used when the Service-Type specifies Framed Access. +-----------+ | Command | | Code | |-----+-----+ Attribute Name | ACR | ACA | ---------------------------------------|-----+-----+ Accounting-Authentication-Type | 1 | 0-1 | Accounting-EAP-Auth-Method | 1 | 0-1 | Accounting-Input-Octets | 1 | 1 | | Accounting-Input-Packets | 1 | 1 | | Accounting-Output-Octets | 1 | 1 | | Accounting-Output-Packets | 1 | 1 | | Acct-Session-Time | 1 | 1 | | Accounting-State | 0 | 0 | Acct-Tunnel-Connection | 0-1 | 0-1 | Acct-Tunnel-Packets-Lost | 0-1 | 0-1 | Framed-AppleTalk-Link | 0-1 | 0-1 | Framed-AppleTalk-Network | 0-1 | 0-1 | Framed-AppleTalk-Zone | 0-1 | 0-1 | Framed-Compression | 0-1 | 0-1 | Framed-IP-Address | 0-1 | 0-1 | Framed-IP-Netmask | 0-1 | 0-1 | Framed-IPX-Network | 0-1 | 0-1 | Framed-MTU | 0-1 | 0-1 | Framed-Protocol | 0-1 | 0-1 | Framed-Route | 0-1 | 0-1 | Framed-Routing | 0-1 | 0-1 | NAS-Filter-Rule | 0-1 | 0-1 | | NAS-Identifier | 0-1 | 0-1 | | NAS-IP-Address | 0-1 | 0-1 | | NAS-Key-Binding | 0 | 0 | | NAS-Port | 0-1 | 0-1 | | NAS-Port-Type | 0-1 | 0-1 | | NAS-Session-Key | 0 | 0 | | Service-Type | 0-1 | 0-1 | State | 0 | 0 | | Tunnel-Assignment-ID | 0-1 | 0-1 | Tunnel-Client-Endpoint | 0-1 | 0-1 | Tunnel-Medium-Type | 0-1 | 0-1 | Tunnel-Private-Group-ID | 0-1 | 0-1 | Tunnel-Server-Endpoint | 0-1 | 0-1 | Tunnel-Type | 0-1 | 0-1 | ---------------------------------------|-----+-----+ Calhoun et al. expires September 2002 [Page 52]
Internet-Draft Diameter NASREQ Application March 2002 10.2.2 Non-Framed Access The table in this section is used when the Service-Type specifies Non-Framed Access. +-----------+ | Command | | Code | |-----+-----+ Attribute Name | ACR | ACA | ---------------------------------------|-----+-----+ Accounting-Authentication-Type | 1 | 0-1 | Accounting-Input-Octets | 1 | 1 | | Accounting-Input-Packets | 0 | 0 | | Accounting-Output-Octets | 1 | 1 | | Accounting-Output-Packets | 0 | 0 | | Acct-Session-Time | 1 | 1 | | Accounting-State | 0 | 0 | Login-IP-Host | 0-1 | 0-1 | Login-LAT-Service | 0-1 | 0-1 | Login-LAT-Node | 0-1 | 0-1 | Login-LAT-Group | 0-1 | 0-1 | Login-LAT-Port | 0-1 | 0-1 | Login-Service | 0-1 | 0-1 | Login-TCP-Port | 0-1 | 0-1 | NAS-Filter-Rule | 0 | 0 | | NAS-Identifier | 0-1 | 0-1 | | NAS-IP-Address | 0-1 | 0-1 | | NAS-Key-Binding | 0 | 0 | | NAS-Port | 0-1 | 0-1 | | NAS-Port-Type | 0-1 | 0-1 | | NAS-Session-Key | 0 | 0 | | Service-Type | 0-1 | 0-1 | State | 0 | 0 | | ---------------------------------------|-----+-----+ 11.0 IANA Considerations This section contains the namespaces that have either been created in this specification, or the values assigned to existing namespaces managed by IANA. 11.1 Command Codes This specification assigns the values 265 and 268 from the Command Code namespace defined in [2]. See sections 3.1 and 4.2 for the Calhoun et al. expires September 2002 [Page 53]
Internet-Draft Diameter NASREQ Application March 2002 assignment of the namespace in this specification. 11.2 AVP Codes This specification assigns the values 363-366 and 400-414 from the | AVP Code namespace defined in [2]. See section 2.1 for the assignment of the namespace in this specification. Note that the values 363-366 | are jointly, but consistently, assigned in [30]. This specification also makes use of AVPs in the 0-255 range, which are defined in [33]. 11.3 Application Identifier This specification assigns the value one (1) to the Application Identifier namespace defined in [1]. See section 1.2 for more information. 11.4 NAS-Key-Binding AVP Values As defined in Section 2.1.6, the NAS-Key-Binding AVP (AVP Code 404) defines the values 1-4. All remaining values, other than zero, are available for assignment via a Designated Expert [12]. 11.5 NAS-Key-Direction AVP Values As defined in Section 2.1.3, the NAS-Key-Direction AVP (AVP Code 406) defines the values 1-3. All remaining values, other than zero, are available for assignment via IETF Consensus [12]. 11.6 NAS-Key-Type AVP Values As defined in Section 2.1.4, the NAS-Key-Type AVP (AVP Code 407) defines the values 1-5. All remaining values, other than zero, are available for assignment via IETF Consensus [12]. 11.7 CHAP-Algorithm AVP Values As defined in Section 3.1.1.4, the CHAP-Algorithm AVP (AVP Code 412) uses the values of the "PPP AUTHENTICATION ALGORITHMS" namespace defined in [6]. Calhoun et al. expires September 2002 [Page 54]
Internet-Draft Diameter NASREQ Application March 2002 12.0 Security Considerations This document does not contain any security protocol, but does discuss how PPP authentication protocols can be carried within the Diameter protocol. The PPP authentication protocols that are described are PAP, CHAP and EAP. The use of PAP SHOULD be discouraged, since it exposes user's passwords to possibly non-trusted entities. PAP is also frequently used for use with One-Time Passwords (OTP), which does not expose any security risks. However, it is highly recommended that OTP be supported through the EAP protocol. This document also describes how CHAP can be carried within the Diameter protocol, which is required for backward RADIUS compatibility. The CHAP protocol, as used in a RADIUS environment, facilitates authentication replay attacks, and therefore SHOULD NOT be used when EAP is available. This specification also defines a method by which the home Diameter server can create and distribute registration keys to be used to authenticate link layer messages (e.g. PPP ECP). The keys SHOULD be be protected using the methods defined in [13]. 13.0 References [1] C. Rigney, A. Rubens, W. Simpson, S. Willens, "Remote Authentica- tion Dial In User Service (RADIUS)", RFC 2865, June 2000. | [2] P. Calhoun, H. Akhtar, J. Arkko, E. Guttman, A. Rubens, J. Lough- | ney, "Diameter Base Protocol", draft-ietf-aaa-diameter-10.txt, IETF | work in progress, March 2002. [3] Aboba, Beadles, "The Network Access Identifier." RFC 2486. January 1999. [4] Aboba, Zorn, "Criteria for Evaluating Roaming Protocols", RFC 2477, January 1999. [5] Hinden, R., Deering, S., "IP Version 6 Addressing Architecture", RFC 2373, July 1998 [6] W. Simpson, "PPP Challenge Handshake Authentication Protocol (CHAP)", RFC 1994, August 1996. Calhoun et al. expires September 2002 [Page 55]
Internet-Draft Diameter NASREQ Application March 2002 [7] Jacobson, "Compressing TCP/IP headers for low-speed serial links", RFC 1144, February 1990. [8] ISO 8859. International Standard -- Information Processing -- 8-bit Single-Byte Coded Graphic Character Sets -- Part 1: Latin Alphabet No. 1, ISO 8859-1:1987. <URL:http://www.iso.ch/cate/d16338.html> [9] Sklower, Lloyd, McGregor, Carr, "The PPP Multilink Protocol (MP)", RFC 1717, November 1994. [10] Reynolds, J., Postel, J., "Assigned Numbers", STD 2, RFC 1700, October 1994 [11] G. Zorn, B. Aboba, D. Mitton, "RADIUS Accounting Modifications for Tunnel Protocol Support", RFC 2867, June 2000. [12] S. Bradner, "Key words for use in RFCs to Indicate Requirement Lev- els", BCP 14, RFC 2119, March 1997. | [13] P. Calhoun, W. Bulley, S. Farrell, "Diameter CMS Security Applica- | tion", draft-ietf-aaa-diameter-cms-sec-04.txt, IETF work in | progress, March 2002. [14] Hamzeh, K., Pall, G., Verthein, W., Taarud, J., Little, W., Zorn, G., "Point-to-Point Tunneling Protocol (PPTP)", RFC 2637, July 1999 [15] Valencia, A., Littlewood, M., Kolar, T., "Cisco Layer Two Forward- ing (Protocol) 'L2F'", RFC 2341, May 1998 [16] Townsley, W. M., Valencia, A., Rubens, A., Pall, G. S., Zorn, G., Palter, B., "Layer Two Tunneling Protocol (L2TP)", RFC 2661, August 1999 [17] Hamzeh, K., "Ascend Tunnel Management Protocol - ATMP", RFC 2107, February 1997 [18] Kent, S., Atkinson, R., "Security Architecture for the Internet Protocol", RFC 2401, November 1998 [19] Perkins, C., "IP Encapsulation within IP", RFC 2003, October 1996 [20] Perkins, C., "Minimal Encapsulation within IP", RFC 2004, October 1996 [21] Atkinson, R., "IP Encapsulating Security Payload (ESP)", RFC 1827, August 1995 Calhoun et al. expires September 2002 [Page 56]
Internet-Draft Diameter NASREQ Application March 2002 [22] Hanks, S., Li, T., Farinacci, D., Traina, P., "Generic Routing Encapsulation (GRE)", RFC 1701, October 1994 [23] Simpson, W., "IP in IP Tunneling", RFC 1853, October 1995 [24] M. Beadles, D. Mitton, "Criteria for Evaluating Network Access Server Protocols", RFC 3169, September 2001. [25] L. J. Blunk, J. R. Vollbrecht, "PPP Extensible Authentication Pro- tocol (EAP)." RFC 2284, March 1998. [26] G. Pall, G. Zorn, "Microsoft Point-To-Point Encryption (MPPE) Pro- tocol", RFC 3078, March 2001. [27] Narten, Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998 [28] G. Zorn, D. Mitton, B. Aboba, "RADIUS Accounting Modifications for Tunnel Protocol Support", RFC 2867, June 2000. [29] F. Yergeau, "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998. | [30] P. Calhoun, C. Perkins, T. Johansson, "Diameter Mobile IP Applica- | tion", draft-ietf-aaa-diameter-mobileip-09.txt, IETF work in | progress, March 2002. [31] G. Zorn, D. Leifer, A. Rubens, J. Shriver, M. Holdrege, I. Goyret, "RADIUS Attributes for Tunnel Protocol Support", RFC 2868, June 2000. [32] C. Rigney, W. Willats, P. Calhoun, "RADIUS Extensions", RFC 2869, June 2000. | [33] IANA, "RADIUS Types", http://www.isi.edu/in-notes/iana/assign- | ments/radius-types [34] C. Rigney, "RADIUS Accounting", RFC 2866, June 2000. [35] K. Sklower, G. Meyer, "The PPP DES Encryption Protocol, Version 2 (DESE-bis)", RFC 2419, September 1998. [36] H. Kummert, "The PPP Triple-DES Encryption Protocol (3DESE)", RFC 2402, September 1998. [37] B. Aboba, G. Zorn, D. Mitton, "RADIUS and IPv6", RFC 3162, August 2001. Calhoun et al. expires September 2002 [Page 57]
Internet-Draft Diameter NASREQ Application March 2002 [38] Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE Std. 802.11-1999, 1999. 14.0 Acknowledgements The authors would like to thank Carl Rigney, Allan C. Rubens, William Allen Simpson, and Steve Willens for their work on the original RADIUS, from which much of the concepts in this specification were derived; Carl Rigney and Ward Willats for [32]; Bernard Aboba and Dave Mitton for [38]; Dory Leifer, John Shriver, Matt Holdrege and Ignacio Goyret for their work on [33]. This document stole text and concepts from both [32] and [33]. Thanks goes to Carl Williams for providing IPv6 specific text. The authors would also like to acknowledge the following people for their contributions in the development of the Diameter protocol: Bernard Aboba, Jari Arkko, William Bulley, Daniel C. Fox, Lol Grant, Nancy Greene, Peter Heitman, Paul Krumviede, Fergal Ladley, Ryan Moats, Victor Muslin, Kenneth Peirce, Sumit Vakil, John R. Vollbrecht and Jeff Weisberg Finally, Pat Calhoun would like to thank Sun Microsystems since most of the effort put into this document was done while he was in their employ. 15.0 Authors' Addresses Questions about this memo can be directed to: Pat R. Calhoun Black Storm Networks 250 Cambridge Avenue, Suite 200 Palo Alto, California, 94306 USA Phone: +1 650-617-2932 Fax: +1 650-786-6445 E-mail: pcalhoun@diameter.org William Bulley Merit Network, Inc. Calhoun et al. expires September 2002 [Page 58]
Internet-Draft Diameter NASREQ Application March 2002 Building One, Suite 2000 4251 Plymouth Road Ann Arbor, Michigan 48105-2785 USA Phone: +1 734-764-9993 Fax: +1 734-647-3185 E-mail: web@merit.edu Allan C. Rubens Tut Systems, Inc. 220 E. Huron, Suite 260 Ann Arbor, MI 48104 USA Phone: +1 734-995-1697 E-Mail: arubens@tutsys.com Jeff Haag Cisco Systems 7025 Kit Creek Road PO Box 14987 Research Triangle Park, NC 27709 Phone: 1-919-392-2353 E-Mail: haag@cisco.com Glen Zorn Cisco Systems, Inc. 500 108th Avenue N.E., Suite 500 Bellevue, WA 98004 USA Phone: +1 425 471 4861 E-Mail: gwz@cisco.com David Spence | Interlink Networks, Inc. | 775 Technology Drive, Suite 200 | Ann Arbor, MI 48108 | USA | Phone: +1 734 821 1203 | Fax: +1 734 821 1235 | Calhoun et al. expires September 2002 [Page 59]
Internet-Draft Diameter NASREQ Application March 2002 EMail: dspence@interlinknetworks.com | 16.0 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. | This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this docu- ment itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of develop- ing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The lim- ited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DIS- CLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. | Calhoun et al. expires September 2002 [Page 60]
