Network Working Group S. Bhandari
Internet-Draft S. Gundavelli
Intended status: Standards Track M. Grayson
Expires: August 10, 2015 B. Volz
Cisco Systems
J. Korhonen
Broadcom Communications
February 6, 2015
Access Network Identifier Option in DHCP
draft-ietf-dhc-access-network-identifier-06
Abstract
This document specifies the format and mechanism that is to be used
for encoding access network identifiers in DHCPv4 and DHCPv6 messages
by defining new access network identifier options and sub-options.
Requirements Language
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 RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on August 10, 2015.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. DHCPv4 Access-Network-Identifier Option . . . . . . . . . . . 5
4.1. DHCPv4 Access-Network-Identifier Sub-options . . . . . . 5
4.2. DHCPv4 Access-Technology-Type Sub-option . . . . . . . . 6
4.3. DHCPv4 Network-Identifier Sub-options . . . . . . . . . . 7
4.3.1. DHCPv4 Network Name Sub-option . . . . . . . . . . . 7
4.3.2. DHCPv4 Access-Point Name Sub-option . . . . . . . . . 8
4.3.3. DHCPv4 Access-Point BSSID Sub-option . . . . . . . . 8
4.4. DHCPv4 Operator Identifier Sub-options . . . . . . . . . 9
4.4.1. DHCPv4 Operator Enterprise ID Sub-option . . . . . . 9
4.4.2. DHCPv4 Operator Realm Sub-option . . . . . . . . . . 9
5. DHCPv6 Access-Network-Identifier Options . . . . . . . . . . 10
5.1. DHCPv6 Access-Technology-Type Option . . . . . . . . . . 11
5.2. DHCPv6 Network-Identifier Options . . . . . . . . . . . . 11
5.2.1. DHCPv6 Network Name Option . . . . . . . . . . . . . 11
5.2.2. DHCPv6 Access-Point Name Option . . . . . . . . . . . 12
5.2.3. DHCPv6 Access-Point BSSID Option . . . . . . . . . . 12
5.3. DHCPv6 Operator Identifier Options . . . . . . . . . . . 13
5.3.1. DHCPv6 Operator Enterprise ID Option . . . . . . . . 13
5.3.2. DHCPv6 Operator Realm Option . . . . . . . . . . . . 13
6. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 14
7. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . 14
8. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
10. Security Considerations . . . . . . . . . . . . . . . . . . . 16
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
12.1. Normative References . . . . . . . . . . . . . . . . . . 17
12.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
Access network identification (ANI) of a network device has a range
of applications. For example the local mobility anchor in a Proxy
Mobile IPv6 domain is able to provide access network and access
operator specific handling or policing of the mobile node traffic
using information about the access network to which the mobile node
is attached.
This document specifies Dynamic Host Configuration Protocol for IPv4
(DHCPv4) [RFC2131] and Dynamic Host Configuration Protocol for IPv6
(DHCPv6) [RFC3315] options for access network identification that is
added by Client or Relay agent in the DHCPv4 or DHCPv6 messages
towards the Server.
Dynamic Host Configuration Protocol (DHCP) client or DHCP relay agent
aware of the access network and access operator add this information
in the DHCP messages. This information can be used to provide
differentiated services and policing of traffic based on the access
network to which a client is attached. Examples of how this
information can be used in mobile networks can be found in [RFC6757].
2. Motivation
Proxy mobile IPv6 [RFC5213] can be used for supporting network-based
mobility management in various types of network deployments. The
network architectures, such as Service provider Wi-Fi access
aggregation or, WLAN integrated mobile packet core are examples where
Proxy Mobile IPv6 is a component of the overall architecture. Some
of these architectures require the ability of the local mobility
anchor (LMA) [RFC5213] to provide differentiated services and
policing of traffic to the mobile nodes based on the access network
to which they are attached. Policy systems in mobility architectures
such as PCC [TS23203] and ANDSF [TS23402] in 3GPP system allow
configuration of policy rules with conditions based on the access
network information. For example, the service treatment for the
mobile node's traffic may be different when they are attached to a
access network owned by the home operator than when owned by a
roaming partner. The service treatment can also be different based
on the configured Service Set Identifiers (SSID) in case of IEEE
802.11 based access networks. Other examples of services include the
operator's ability to apply tariff based on the location.
The PMIPv6 extension as specified in [RFC6757] defines PMIPv6 options
to carry access network identifiers in PMIPv6 signaling from Mobile
Access Gateway (MAG) to LMA. MAG can learn this information from
DHCP options as inserted by DHCP client or Relay agent before MAG.
If MAG relays DHCP messages to LMA as specified in [RFC5844] this
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information can be inserted by MAG towards LMA in the forwarded DHCP
messages.
Figure 1 illustrates an example Proxy Mobile IPv6 deployment where
Access Points (AP) acting as a DHCP relay agent inserts access
network identifiers in DHCP messages relayed from the connected
clients. The mobile access gateway learns this information over DHCP
and delivers the information elements related to the access network
to the local mobility anchor over Proxy Mobile IPv6 signaling
messages. In this example, the additional information could comprise
the SSID of the used IEEE 802.11 network and the identities of the
operators running the IEEE 802.11 access network infrastructure.
SSID: IETF-1
Operator-Id: provider1.example
+--+ DHCP
|AP|-------. {Access Specific Policies)
+--+ | _-----_ |
+-----+ _( )_ +-----+
| MAG |-=====( PMIPv6 )======-| LMA |-
+-----+ (_ Tunnel_) +-----+
+--+ DHCP | '-----'
|AP|-------'
+--+
SSID: IETF-2
Operator-Id: provider2.example
Access Networks attached to MAG
3. Terminology
All the DHCP related terms used in this document are to be
interpreted as defined in the Dynamic Host Configuration Protocol
(DHCPv4) [RFC2131] and Dynamic Host Configuration Protocol for IPv6
(DHCPv6) [RFC3315] specifications. DHCP message refers to both
DHCPv4 and DHCPv6 messages throughout this document.
All the mobility related terms used in this document are to be
interpreted as defined in the Proxy Mobile IPv6 specifications
[RFC5213] and [RFC5844]. Additionally, this document uses the
following abbreviations:
Service Set Identifier (SSID)
Service Set Identifier (SSID) identifies the name of the IEEE
802.11 network. SSID differentiates from one network to the
other.
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Vendor ID
The Vendor ID is the SMI Network Management Private Enterprise
Code of the IANA-maintained Private Enterprise Numbers registry
[SMI].
4. DHCPv4 Access-Network-Identifier Option
The Access Network Identifier option carries information to identify
the access network to which the client is attached. This information
includes access technology type, network identifier, and access-
network operator identifiers.
The format of the DHCPv4 Access-Network-Identifier option is shown
below.
Code Len ANI Sub-options
+------+------+------+------+------+-- --+-----+
| code | len | s1 | s2 | s2 | ... | sN |
+------+------+------+------+------+-- --+-----+
Code
OPTION_ACCESS_NETWORK_ID (<IANA-0>).
Len
The length of the ANI Sub-options field.
ANI Sub-Options (s1 to sN)
The sub-option(s).
The client inserts the Access Network Identifier option that contains
one or more sub-options, as defined in Section 4.1.
Relay agents that want to include Access Network Identifier
information include one or more sub-options (see Section 4.1) in the
Relay Agent Information option [RFC3046].
Note that both the client and Relay agent sub-options codes are the
same and are allocated from the DHCP Relay Agent Sub-Option Codes.
4.1. DHCPv4 Access-Network-Identifier Sub-options
The access network identifier information will be defined in multiple
sub-options, allocated from the DHCP Relay Agent Sub-Option Codes.
ANI Sub-options: The ANI Sub-options consists of a sequence of Sub-
Option Code, Length, and Value tuples for each sub-option, encoded in
the following manner:
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SubOpt Len Sub-option Data
+------+------+------+------+------+------+--...-+------+
| code | N | s1 | s2 | s3 | s4 | | sN |
+------+------+------+------+------+------+--...-+------+
Subopt code
The 1-octet code for the sub-options defined in the following
sections.
Len
An unsigned 8-bit integer giving the length of the Sub-option Data
field in this sub-option in octets.
Sub-option Data (s1 to sN)
The data area for the sub-option.
The initial assignment of DHCP access network identifier sub-options
is as follows:
+=================+=======================================+
| SUB-OPTION CODE | SUB-OPTION DESCRIPTION |
+=================+=======================================+
| <IANA-1> | Access Technology Type Sub-option |
+=========================================================+
| <IANA-2> | Access Network Name Sub-option |
+=========================================================+
| <IANA-3> | Access Point Name Sub-option |
+=========================================================+
| <IANA-4> | Access Point BSSID Sub-option |
+=========================================================+
| <IANA-5> | Operator-Identifier Sub-option |
+=========================================================+
| <IANA-6> | Operator-Realm Sub-option |
+=========================================================+
4.2. DHCPv4 Access-Technology-Type Sub-option
This sub-option is used for exchanging the type of the access
technology of the network to which the client is attached. Its
format is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | Reserved | ATT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
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<IANA-1>.
Length
2.
Reserved
An 8-bit field that is unused for now. The value MUST be
initialized to 0 by the sender and MUST be ignored by the
receiver.
Access-Technology-Type (ATT)
An 8-bit field that specifies the access technology through which
the client is connected to the access link from the IANA name
space Access Technology Type Option type value registry defined in
[RFC5213].
4.3. DHCPv4 Network-Identifier Sub-options
These sub-options are used for carrying the name of the access
network (e.g., a SSID in case of IEEE 802.11 Access Network, or PLMN
Identifier [TS23003] in case of 3GPP access) and Access Point name to
which the client is attached. The format of these sub-options is
defined the following sections.
4.3.1. DHCPv4 Network Name Sub-option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
. .
. Network Name (e.g., SSID or PLMNID) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-2>.
Length
The length of the Network Name field.
Network Name
The name of the access network to which the mobile node is
attached. The encoding MUST be UTF-8 as described in [RFC3629].
The type of the Network Name is dependent on the access technology
to which the mobile node is attached. If it is 802.11 access, the
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Network Name MUST be the SSID of the network. If the access
network is 3GPP access, the Network Name is the PLMN Identifier of
the network. If the access network is 3GPP2 access, the Network
Name is the Access Network Identifier [ANI].
When encoding the PLMN Identifier, both the Mobile Network Code
(MNC) [TS23003] and Mobile Country Code (MCC) [TS23003] MUST be 3
digits. If the MNC in use only has 2 digits, then it MUST be
preceded with a '0'.
4.3.2. DHCPv4 Access-Point Name Sub-option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
. .
. Access-Point Name .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-3>.
Length
The length of the Access-Point Name field.
Access-Point Name
The name of the access point (physical device name) to which the
mobile node is attached. This is the identifier that uniquely
identifies the access point. While Network Name (e.g., SSID)
identifies the operator's access network, Access-Point Name
identifies a specific network device in the network to which the
mobile node is attached. In some deployments, the Access-Point
Name can be set to the string representation of the Media Access
Control (MAC) address as specified in [RFC6021] mac-address string
type of the device or some unique identifier that can be used by
the policy systems in the operator network to unambiguously
identify the device. The encoding MUST be UTF-8 as described in
[RFC3629].
4.3.3. DHCPv4 Access-Point BSSID Sub-option
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Access-Point BSSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-4>.
Length
6.
Access-Point BSSID
The 48-bit Basic Service Set Identification (BSSID) of the access
point to which the mobile node is attached.
4.4. DHCPv4 Operator Identifier Sub-options
The Operator identifier sub-options can be used for carrying the
operator identifier of the access network to which the client is
attached. The format of these sub-options is defined below.
4.4.1. DHCPv4 Operator Enterprise ID Sub-option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Operator Enterprise ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-5>.
Length
4.
Operator Enterprise ID (4-Octets)
The operator's Vendor ID.
4.4.2. DHCPv4 Operator Realm Sub-option
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subopt Code | Length | |
|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
. .
. Operator Realm .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-6>.
Length
The length of the Operator Realm field.
Operator Realm
Realm of the operator. Realm names are required to be unique, and
are piggybacked on the administration of the DNS namespace.
Realms are encoded using a domain name encoding defined in
[RFC1035].
5. DHCPv6 Access-Network-Identifier Options
The Access Network Identifier options defined here may be added by
the DHCPv6 client in upstream DHCPv6 messages or by the Relay agent
in Relay-forward messages.
+=================+=======================================+
| OPTION CODE | OPTION DESCRIPTION |
+=================+=======================================+
| <IANA-7> | OPTION_ANI_ATT |
+=========================================================+
| <IANA-8> | OPTION_ANI_NETWORK_NAME |
+=========================================================+
| <IANA-9> | OPTION_ANI_AP_NAME |
+=========================================================+
| <IANA-10> | OPTION_ANI_AP_BSSID |
+=========================================================+
| <IANA-11> | OPTION_ANI_OPERATOR_ID |
+=========================================================+
| <IANA-12> | OPTION_ANI_OPERATOR_REALM |
+=========================================================+
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5.1. DHCPv6 Access-Technology-Type Option
This option is used for exchanging the type of the access technology
the client is attached to the network. Its format is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_ATT | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | ATT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_ATT (<IANA-7>).
Option-Len
2.
Reserved
An 8-bit field that is unused for now. The value MUST be
initialized to 0 by the sender and MUST be ignored by the
receiver.
Access Technology Type (ATT):
The contents of this field is the same as the ATT field described
in Section 4.2.
5.2. DHCPv6 Network-Identifier Options
These options can be used for carrying the name of the access network
(e.g., a SSID in case of IEEE 802.11 Access Network, or PLMN
Identifier [TS23003] in case of 3GPP access) and Access Point name to
which the client is attached. The format of these options is defined
below.
5.2.1. DHCPv6 Network Name Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_NETWORK_NAME | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Network Name (e.g., SSID or PLMNID) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Option-Code
OPTION_ANI_NETWORK_NAME (<IANA-8>).
Option-Len
The length of the Network Name field.
Network Name
The contents of this field is the same as the Network Name field
described in Section 4.3.1.
5.2.2. DHCPv6 Access-Point Name Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_AP_NAME | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Access-Point Name .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_AP_NAME (<IANA-9>).
Option-Len
The length of the Access-Point Name field.
Access-Point Name
The contents of this field is the same as the Access-Point Name
field described in Section 4.3.2.
5.2.3. DHCPv6 Access-Point BSSID Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_AP_BSSID | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Point BSSID |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_AP_BSSID (<IANA-10>).
Option-Len
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6.
Access-Point BSSID
The contents of this field is the same as the Access-Point BSSID
field described in Section 4.3.3.
5.3. DHCPv6 Operator Identifier Options
The Operator Identifier options can be used for carrying the operator
identifier of the access network to which the client is attached.
The format of these options is defined below.
5.3.1. DHCPv6 Operator Enterprise ID Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_OPERATOR_ID | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operator Enterprise ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_OPERATOR_ID (<IANA-11>).
Option-Len
4.
Operator Enterprise ID
The operator's Vendor ID.
5.3.2. DHCPv6 Operator Realm Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ANI_OPERATOR_REALM | Option-Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Operator Realm .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_OPERATOR_REALM (<IANA-12>).
Option-Len
The length of the Operator Realm field.
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Operator Realm
The contents of this field is the same as the Operator Realm field
described in Section 4.4.2.
6. Client Behavior
DHCPv4 clients MAY include the DHCPv4 ANI option define in Section 4,
including one or more sub-options within the option, as defined in
sections 4.1 through 4.4 in all the upstream DHCPv4 messages to
inform the receiver about the access network it is attached to.
DHCPv6 clients MAY include DHCPv6 ANI options, as defined in
Section 5.
It is implementation specific as which ANI options and sub-options
the client includes.
7. Relay Agent Behavior
DHCPv4 Relay Agents MAY include sub-options defined in section 4.2
through 4.4 in the Relay Agent Information option as defined in
[RFC3046] before forwarding the DHCP message to provide information
about the access network over which DHCP messages from the client is
received. DHCPv4 Relay agent MAY include the sub-options in Relay
Agent Information option even if the DHCPv4 ANI option is inserted by
the DHCPv4 client in the received DHCPv4 message based on its
configured policy.
DHCPv6 Relay Agents MAY include options defined in Section 5 in
Relay-forward message when forwarding any DHCPv6 message type from
clients to the servers to provide information about the access
network over which DHCPv6 messages from the client is received.
DHCPv6 Relay Agent MAY include options defined in Section 5 in Relay-
forward message even if the same options have been included by the
DHCPv6 client in the received DHCPv6 message based on its configured
policy.
8. Server Behavior
If DHCPv4 server does not understand the option defined in Section 4
it must ignore the DHCPv4 Access Network Identifier option received.
If the DHCPv4 server does not understand the received sub-option
defined in sections 4.1 through 4.4 either in the DHCPv4 Access
Network Identifier option or in Relay Agent Information option (82)
it must ignore those sub-options only. If DHCPv4 Server is able to
process the DHCPv4 Access Network Identifier and sub-options defined
in sections 4.1 through 4.4 received in DHCPv4 Access Network
Identifier or Relay Agent Information option, it MAY use this
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information for address pool selection policy decisions as per its
configured policy. The DHCPv4 server MAY store this information
along with the lease for logging and audit purpose. The DHCPv4
server MAY use the sub-options defined in sections 4.1 through
section 4.4 inserted by the DHCPv4 client in the DHCPv4 Access
Network Identifier option or by the DHCPv4 relay agent in the Relay
Agent Information option based on its configured policy. When
generating a response, the server echoes back Relay Agent Information
options with all received sub-options in it, as specified in
Section 2.2 of [RFC3046].
If the DHCPv6 server receives the options defined in Section 5 and is
configured to store or use the options defined in Section 5, it
SHOULD look for the DHCPv6 Access Network identifier options in the
Relay-forward message of the DHCPv6 relay agent(s) or from the DHCPv6
client based on its configured policy. The server MAY use received
ANI options for its address pool selection policy decisions as per
its configured policy.
9. IANA Considerations
This document defines DHCPv4 Access Network Identifier option which
requires assignment of DHCPv4 option code IANA-0 assigned from "BOOTP
Vendor Extensions and DHCP Options" registry
<http://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-
parameters.xml>, as specified in [RFC2939].
IANA is requested to assign Sub-option codes for the following DHCPv4
Sub-options from the "DHCP Relay Agent Sub-Option Codes":
+=================+=======================================+
| SUB-OPTION CODE | SUB-OPTION DESCRIPTION |
+=================+=======================================+
| <IANA-1> | Access Technology Type Sub-option |
+=========================================================+
| <IANA-2> | Access Network Name Sub-option |
+=========================================================+
| <IANA-3> | Access Point Name Sub-option |
+=========================================================+
| <IANA-4> | Access Point BSSID Sub-option |
+=========================================================+
| <IANA-5> | Operator-Identifier Sub-option |
+=========================================================+
| <IANA-6> | Operator-Realm Sub-option |
+=========================================================+
IANA is requested to assign option codes for the following DHCPv6
options from the "Option Codes registry for DHCPv6" registry
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<http://www.iana.org/assignments/dhcpv6-parameters/
dhcpv6-parameters.xml>, as specified in [RFC3315]:
+=================+=======================================+
| OPTION CODE | OPTION DESCRIPTION |
+=================+=======================================+
| <IANA-7> | OPTION_ANI_ATT |
+=========================================================+
| <IANA-8> | OPTION_ANI_NETWORK_NAME |
+=========================================================+
| <IANA-9> | OPTION_ANI_AP_NAME |
+=========================================================+
| <IANA-10> | OPTION_ANI_AP_BSSID |
+=========================================================+
| <IANA-11> | OPTION_ANI_OPERATOR_ID |
+=========================================================+
| <IANA-12> | OPTION_ANI_OPERATOR_REALM |
+=========================================================+
10. Security Considerations
Since there is no privacy protection for DHCP messages, an
eavesdropper who can monitor the link between the DHCP server, relay
agent and client can discover access network information.
To minimize the unintended exposure of this information, this option
SHOULD be included by DHCP entities only when it is configured.
Where critical decisions might be based on the value of this option,
DHCP authentication as defined in "Authentication for DHCP Messages"
[RFC3118] and "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)"
[RFC3315] SHOULD be used to protect the integrity of the DHCP
options. Link-layer confidentiality and integrity protection may
also be employed to reduce the risk of disclosure and tampering.
Security issues related DHCPv6 are described in section 23 of
[RFC3315].
DHCP clients can fake its Access Network Identifier option values to
gain better service. DHCP Servers and Relay agents should be
configured with suitable policy to override or trust the access
network information received from DHCP clients.
It is possible for a rogue DHCP relay agent to insert or overwrite
with incorrect access network identifier options for malicious
purposes. A DHCP client can also pose as a rogue DHCP relay agent by
sending incorrect access network identifier options. While the
introduction of fraudulent DHCP relay agent information options can
be prevented by a perimeter defense that blocks these options unless
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the DHCP relay agent is trusted, a deeper defense using the
authentication sub-option for DHCPv4 relay agent information option
[RFC4030] SHOULD be deployed as well. DHCP server administrators are
strongly advised to configure DHCP servers that use this option to
communicate with their relay agents using IPsec, as described in
Section 21.1 of [RFC3315].
11. Acknowledgements
The authors would like to thank Kim Kinnear, Ted Lemon, Gaurav
Halwasia, Hidetoshi Yokota and Sheng Jiang for their valuable inputs.
And, to Tomek Mrugalski for a thorough review of the document.
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.
[RFC3046] Patrick, M., "DHCP Relay Agent Information Option", RFC
3046, January 2001.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
12.2. Informative References
[ANI] "Interoperability Specification (IOS) for High Rate Packet
Data (HRPD) Radio Access Network Interfaces with Session
Control in the Access Network, A.S0008-A v3.0", October
2008.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition
of New DHCP Options and Message Types", BCP 43, RFC 2939,
September 2000.
[RFC3118] Droms, R. and W. Arbaugh, "Authentication for DHCP
Messages", RFC 3118, June 2001.
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[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[RFC4030] Stapp, M. and T. Lemon, "The Authentication Suboption for
the Dynamic Host Configuration Protocol (DHCP) Relay Agent
Option", RFC 4030, March 2005.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
October 2010.
[RFC6757] Gundavelli, S., Korhonen, J., Grayson, M., Leung, K., and
R. Pazhyannur, "Access Network Identifier (ANI) Option for
Proxy Mobile IPv6", RFC 6757, October 2012.
[SMI] "PRIVATE ENTERPRISE NUMBERS, SMI Network Management
Private Enterprise Codes", February 2011.
[TS23003] "Numbering, addressing and identification", 2011.
[TS23203] "Policy and Charging Control Architecture", 2012.
[TS23402] "Architecture enhancements for non-3GPP accesses", 2012.
Authors' Addresses
Shwetha Bhandari
Cisco Systems
Cessna Business Park, Sarjapura Marathalli Outer Ring Road
Bangalore, KARNATAKA 560 087
India
Phone: +91 80 4426 0474
Email: shwethab@cisco.com
Sri Gundavelli
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
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Mark Grayson
Cisco Systems
11 New Square Park
Bedfont Lakes, FELTHAM TW14 8HA
ENGLAND
Email: mgrayson@cisco.com
Bernie Volz
Cisco Systems
1414 Massachusetts Ave
Boxborough,, MA 01719
USA
Email: volz@cisco.com
Jouni Korhonen
Broadcom Communications
Porkkalankatu 24
FIN-00180 Helsinki
Finland
Email: jouni.nospam@gmail.com
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