RADIUS Extensions for Port Control Protocol
draft-maglione-pcp-radius-ext-03
The information below is for an old version of the document.
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|---|---|---|---|
| Authors | Dean Cheng , Roberta Maglione | ||
| Last updated | 2011-12-22 (Latest revision 2011-06-23) | ||
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draft-maglione-pcp-radius-ext-03
pcp R. Maglione
Internet-Draft Telecom Italia
Intended status: Standards Track D. Cheng
Expires: June 24, 2012 Huawei Technologies
December 22, 2011
RADIUS Extensions for Port Control Protocol
draft-maglione-pcp-radius-ext-03
Abstract
This memo proposes a new Remote Authentication Dial In User Service
(RADIUS) attribute to carry the Fully Qualified Domain Name (FQDN) of
a Port Control Protocol (PCP) server, such that while the PCP server
information is configured on a RADIUS server, the information can be
conveyed to Network Access Server (NAS) via RADIUS protocol, and the
co-located Dynamic Host Configuration Protocol (DHCP/DHCPv6) server
can then populate the information to PCP client.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on June 24, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. PCP Server Configuration using RADIUS and DHCP/DHCPv6 . . . . 4
4. RADIUS Attribute . . . . . . . . . . . . . . . . . . . . . . . 8
5. Table of attributes . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References . . . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Introduction
Port Control Protocol (PCP) [I-D.ietf-pcp-base] provides a mechanism
to control how incoming packets are forwarded by upstream devices
such as NATs and firewalls. PCP is a client-server protocol where a
PCP client may reside on a host, a Customer Premises Equipment (CPE),
etc., which communicates with a PCP server that may reside anywhere
in a network.
A PCP client must know the Fully Qualified Domain Name (FQDN) of a
PCP server, before it can communicate with the later in order to
perform the relevant PCP functions.
[I-D.ietf-pcp-dhcp] defines DHCPv6 and DHCP options which are meant
to be used by a PCP client to discover a PCP server name. However,
provisioning for name of the PCP server is required on a DHCP/DHCPv6
server before it can populate these information.
Auto-configuration on a DHCP/DHCPv6 is possible in a broadband
network, where typically, user profile is maintained on a Remote
Authentication Dial In User Service (RADIUS) server and RADIUS
protocol [RFC2865] is used to convey user related information to
other network elements including a host and CPE.
[I-D.ietf-radext-ipv6-access] describes a typical broadband network
scenario in which the Network Access Server (NAS) acts as the access
gateway for the users (hosts or CPEs) and the NAS embeds a DHCPv6
Server function that allows it to locally handle any DHCPv6 requests
issued by the clients.
In such environment, PCP server's name can be configured on a RADIUS
server, which then passes the information to a NAS that co-locates
with the DHCP/DHCPv6 server, which in turn populates the location of
the PCP server.
This memo defines a new RADIUS attribute that can be used to carry
the FQDN of a PCP server.
The approach described above is already used for providing the FQDN
of the AFTR in the DS-Lite scenario and the equivalent RADIUS
attribute for the DS-Lite Tunnel Name is defined
[I-D.ietf-softwire-dslite-radius-ext].
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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The following terms are defined in [I-D.ietf-pcp-base]:
- Port forwarding
- PCP
- PCP client
- PCP Server
3. PCP Server Configuration using RADIUS and DHCP/DHCPv6
Figure 1 illustrates how RADIUS protocol works together with DHCPv6,
to allow a host to learn automatically the FQDN of a PCP server in
case of a PPP session that carries IPv6 traffic.
The Network Access Server (NAS) operates as a client of RADIUS and
co-locates with a DHCPv6 Server for DHCPv6 protocol. The NAS
initially sends a RADIUS Access Request message to the RADIUS server,
requesting authentication. Once the RADIUS server receives the
request, it validates the sending client and if the request is
approved, the RADIUS server replies with an Access Accept message
including a list of attribute-value pairs that describe the
parameters to be used for this session. This list MAY also contain
the name of a PCP server. When the co-located DHCPv6 server receives
a DHCPv6 message containing the PCP Server Option, it SHALL use the
name returned in the RADIUS attribute as defined in this memo to
populate the DHCPv6 PCP Server option defined in [I-D.ietf-pcp-dhcp]
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PCP/DHCPv6 NAS AAA
Client DHCPv6 Server Server
| | |
|----PPP LCP Config Request------> | |
| | |
| |----Access-Request ---->|
| | |
| |<-Access-Accept---------|
| | (PCP-server-name) |
|<-----PPP LCP Config ACK ----- | |
| | |
| | |
|------ PPP IPV6CP Config Req ---->| |
| | |
|<----- PPP IPV6CP Config ACK -----| |
| | |
|------- DHCPv6 Solicit -------->| |
| | |
|<-------DHCPv6 Advertisement------| |
| (PCP server FQDN DHCPv6 Option) | |
| | |
|------- DHCPv6 Request -------->| |
| (PCP server FQDN DHCPv6 Option) | |
| | |
|<-------- DHCPv6 Reply --------- | |
| (PCP server FQDN DHCPv6 Option) | |
| | |
DHCPv6 RADIUS
Figure 1: RADIUS and DHCPv6 Message Flow for a PPP Session
The Figure 2 illustrates how the RADIUS protocol and DHCPv6 work
together to accomplish PCP client configuration when DHCPv6 is used
to provide connectivity to the user.
The difference between this message flow and previous one is that in
this scenario the interaction between NAS and AAA/ RADIUS Server is
triggered by the DHCPv6 Solicit message received by the NAS from the
B4 acting as DHCPv6 client, while in case of a PPP Session the
trigger is the PPP LCP Config Request message received by the NAS.
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PCP/DHCPv6 NAS AAA
Client DHCPv6 Server Server
| | |
|------ DHCPv6 Solicit ---------> | |
| | |
| |----Access-Request ---->|
| | |
| |<-Access-Accept---------|
| | (PCP-server-name) |
| | |
|<-------DHCPv6 Advertisement------| |
| (PCP server FQDN DHCPv6 Option) | |
| | |
|------- DHCPv6 Request -------->| |
| (PCP server FQDN DHCPv6 Option) | |
| | |
| <-------- DHCPv6 Reply --------- | |
| (PCP server FQDN DHCPv6 Option) | |
DHCPv6 RADIUS
Figure 2: RADIUS and DHCPv6 Message Flow for an IP Session
In the scenario depicted in Figure 2 the Access-Request packet
contains a Service-Type attribute with the value Authorize Only (17),
thus according to [RFC5080] the Access-Request packet MUST contain a
State attribute.
A similar message flow also applies to the IPv4 scenario when DHCPv4
is used to provide connectivity to the user (Figure 3).
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PCP/DHCP NAS AAA
Client DHCP Server Server
| | |
|-------- DHCP Discovery --------> | |
| | |
| |----Access-Request ---->|
| | |
| |<-Access-Accept---------|
| | (PCP-server-name) |
| | |
|<--------- DHCP Offer ------------| |
| (PCP server FQDN Sub-Option) | |
| | |
|--------- DHCP Request -------->| |
| (PCP server FQDN Sub-Option) | |
| | |
| <--------- DHCP Ack -------------| |
| (PCP server FQDN Sub-Option) | |
DHCPv4 RADIUS
Figure 3: RADIUS and DHCPv4 Message Flow for an IP Session
After receiving the PCP server name in the initial Access-Accept the
NAS MUST store the received PCP Server Name locally. When the PCP
Client sends a DHCP message to request an extension of the lifetimes
for the assigned address or prefix, the NAS does not have to initiate
a new Access-Request towards the AAA server to request the PCP server
name. The NAS retrieves the previously stored PCP Server name and
uses it in its reply.
If the DHCP server to which the DHCP Renew message was sent at time
T1 has not responded, the DHCP client initiates a Rebind/Reply
exchange with any available server. In this scenario the NAS MUST
initiate a new Access-Request towards the AAA server, after the co-
located DHCP server receives the DHCP message. The NAS MAY include
the PCP Server Name attribute in its Access-Request.
If the NAS does not receive the PCP server name attribute in the
Access-Accept it MAY fallback to a pre-configured default tunnel
name, if any. If the NAS does not have any pre-configured default
tunnel name or if the NAS receives an Access-Reject, the PCP client
can not be configured by the NAS.
The scenario with PPP Session and IPv4 only connectivity does not
require the DHCP protocol: the whole configuration of the client is
performed by PPP. This case is out of scope of this document because
in order to complete the configuration of the PCP client a new PPP
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IPC option would be required.
4. RADIUS Attribute
A new RADIUS attribute, called PCP-Server-Name, along with its format
is defined below.
Description
The PCP-server-name attribute contains a Fully Qualified Domain Name
(FQDN) that refers to a PCP server the client requests to establish a
connection to for PCP related service. The NAS shall use the name
returned in the RADIUS PCP-server-name attribute to populate the PCP
Server FQDN DHCP Sub-Option in IPv4 addressing context, or the PCP
Server FQDN DHCPv6 Option in IPv6 addressing context, as determined
by the DHCP server [I-D.ietf-pcp-dhcp]
The PCP-server-name attribute MAY appear in an Access-Accept packet.
This attribute MAY be used in Access-Request packets as a hint to the
RADIUS server; for example if the NAS is pre-configured with a
default PCP server name, this name MAY be inserted in the attribute.
The RADIUS server MAY ignore the hint sent by the NAS and it MAY
assign a different PCP Server name. If the NAS includes the PCP
Server Name attribute, but the AAA server does not recognize it, this
attribute MUST be ignored by the AAA Server. If the NAS does not
receive PCP Server Name attribute in the Access-Accept it MAY
fallback to a pre-configured default PCP server name, if any. If the
NAS is pre-provisioned with a default PCP server name and the PCP
server name received in Access-Accept is different from the
configured default, then the PCP server name received in the Access-
Accept message MUST be used for the session.
The PCP server Name RADIUS attribute MAY be present in Accounting-
Request records where the Acct-Status-Type is set to Start, Stop or
Interim-Update. The PCP Server Name RADIUS attribute MUST NOT appear
more than once in a message.
A summary of the PCP-Server-Name RADIUS attribute format is shown
below. The fields are transmitted from left to right.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | PCP-Server-Name (FQDN) ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type:
TBA1 for PCP-Server-Name.
Length:
This field indicates the total length in octets of this
attribute including the Type, the Length fields and the length
in octets of the PCP-Server-Name field
PCP-Server-Name:
A single Fully Qualified Domain Name of the PCP-Server. The
domain name is encoded as specified in [RFC1035]
The data type of PCP Server Name is a string with opaque
encapsulation, according to section 2.1 of [RFC6158]
5. Table of attributes
The following table provides a guide to which attributes may be found
in which kinds of packets, and in what quantity.
Request Accept Reject Challenge Accounting # Attribute
Request
0-1 0-1 0 0 0-1 TBA1 PCP-Server-Name
The following table defines the meaning of the above table entries.
0 This attribute MUST NOT be present in packet.
0+ Zero or more instances of this attribute MAY be present in
packet.
0-1 Zero or one instance of this attribute MAY be present in packet.
6. Security Considerations
This document has no additional security considerations beyond those
already identified in [RFC2865].
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7. IANA Considerations
This document requests the allocation of a new Radius attribute types
from the IANA registry "Radius Attribute Types" located at
http://www.iana.org/assignments/radius-types
PCP-Server-Name - TBA1
8. Acknowledgments
The authors would like to thank Mohamed Boucadair and Mario Ullio for
their valuable comments.
9. References
9.1. Normative References
[I-D.ietf-pcp-base]
Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
Selkirk, "Port Control Protocol (PCP)",
draft-ietf-pcp-base-19 (work in progress), December 2011.
[I-D.ietf-pcp-dhcp]
Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
the Port Control Protocol (PCP)", draft-ietf-pcp-dhcp-01
(work in progress), November 2011.
[I-D.ietf-softwire-dslite-radius-ext]
Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", draft-ietf-softwire-dslite-radius-ext-07
(work in progress), October 2011.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[RFC5080] Nelson, D. and A. DeKok, "Common Remote Authentication
Dial In User Service (RADIUS) Implementation Issues and
Suggested Fixes", RFC 5080, December 2007.
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[RFC6158] DeKok, A. and G. Weber, "RADIUS Design Guidelines",
BCP 158, RFC 6158, March 2011.
9.2. Informative References
[I-D.ietf-radext-ipv6-access]
Lourdelet, B., Dec, W., Sarikaya, B., Zorn, G., and D.
Miles, "RADIUS attributes for IPv6 Access Networks",
draft-ietf-radext-ipv6-access-06 (work in progress),
November 2011.
Authors' Addresses
Roberta Maglione
Telecom Italia
Via Reiss Romoli 274
Torino 10148
Italy
Phone:
Email: roberta.maglione@telecomitalia.it
Dean Cheng
Huawei Technologies
2330 Central Expressway
Santa Clara, CA 95050
USA
Phone: +1 408 330 4754
Fax:
Email: Chengd@huawei.com
URI:
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