Internet DRAFT - draft-ietf-dhc-access-network-identifier
draft-ietf-dhc-access-network-identifier
Network Working Group S. Bhandari
Internet-Draft S. Gundavelli
Intended status: Standards Track M. Grayson
Expires: August 4, 2016 B. Volz
Cisco Systems
J. Korhonen
Broadcom Communications
February 01, 2016
Access Network Identifier Option in DHCP
draft-ietf-dhc-access-network-identifier-13
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.
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
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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 4, 2016.
Copyright Notice
Copyright (c) 2016 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
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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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 . . . . . . . . . 9
4.4. DHCPv4 Operator Identifier Sub-options . . . . . . . . . . 9
4.4.1. DHCPv4 Operator-Identifier Sub-option . . . . . . . . 9
4.4.2. DHCPv4 Operator-Realm Sub-option . . . . . . . . . . . 10
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-Identifier Option . . . . . . . . . . 13
5.3.2. DHCPv6 Operator-Realm Option . . . . . . . . . . . . . 13
6. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . 14
7. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 14
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
11.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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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 Relay agent in the DHCPv4 or DHCPv6 messages towards the
Server. The scope of applicability for this option is between a DHCP
relay agent and a mobile access gateway where the same operator
typically operates both these functions
Dynamic Host Configuration Protocol (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
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Access Gateway (MAG) to LMA. MAG can learn this information from
DHCP options as inserted by DHCP Relay agent before MAG. If MAG
relays DHCP messages to LMA as specified in [RFC5844] this
information can be inserted by MAG towards LMA in the forwarded DHCP
messages.
Figure 1, illustrates an example Proxy Mobile IPv6 deployment. In
this example, the access network is IEEE 802.11 based access-network,
the DHCP Relay Agent function is located on the access point (AP),
and the DHCP Server function is located on the MAG. The MAG delivers
the information elements related to the access network to the LMA
over Proxy Mobile IPv6 signaling messages. The MAG obtains these
information elements from the DHCP Relay Agent as per this
specification. The informational elements related to the access
network include the SSID of the used IEEE 802.11 network, the geo-
location of the access-network to which the mobile node is attached,
and the identity of the operator running the IEEE 802.11 access
network infrastructure.
SSID: IETF-1
Operator-Id: provider1.example
+--+
|AP|-----------. {Access Specific Policies)
+--+ | (DHCP Server) _-----_ |
(DHCP Relay) +-----+ _( )_ +-----+
| MAG |-=========( PMIPv6 )======-| LMA |-
+-----+ (_ Tunnel_) +-----+
+--+ | '-----'
|AP|-----------'
+--+
(DHCP Relay)
SSID: IETF-2
Operator-Id: provider2.example
Access Networks attached to MAG
3. 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].
All the DHCP related terms used in this document are to be
interpreted as defined in the Dynamic Host Configuration Protocol
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(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.
Operator-Identifier
The Operator-Identifier is the Structure of Management Information
(SMI) Network Management Private Enterprise Code of the IANA-
maintained "Private Enterprise Numbers" registry [SMI]. It
identifies the operator running the access-network where the
client is attached.
4. DHCPv4 Access-Network-Identifier Option
The Access Network Identifier 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.
Relay agents that include Access Network Identifier information
include one or more sub-options (see Section 4.1) in the Relay Agent
Information option [RFC3046].
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:
SubOpt Len Sub-option Data
+------+------+------+------+------+------+--...-+------+
| code | N | s1 | s2 | s3 | s4 | | sN |
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+------+------+------+------+------+------+--...-+------+
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Subopt Code
<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. The Network-Identifier sub-options
are only for the currently known access technology types.
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.
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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. For IEEE 802.11 based
networks, the network name will be the SSID of the network. For
3GPP access based it is the PLMN Identifier of the access network
and for 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 [RFC6991] 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].
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4.3.3. DHCPv4 Access-Point BSSID 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 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 identifiers of the access network to which the client is
attached. The format of these sub-options is defined below.
4.4.1. DHCPv4 Operator-Identifier 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-Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code <IANA-5>.
Length
4.
Operator-Identifier Operator-Identifier as a variable-length Private
Enterprise Number (PEN) [SMI] encoded in a network-byte order.
Please refer to (section 3.1.3 of [RFC6757]) for additional
details.
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4.4.2. DHCPv4 Operator-Realm 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-Realm .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subopt Code
<IANA-6>.
Length
The length of the Operator Realm field.
Operator-Realm
Realm of the operator (e.g., EXAMPLE.COM). Please refer to
(section 3.1.3 of [RFC6757]) for additional details.
5. DHCPv6 Access-Network-Identifier Options
The Access Network Identifier options defined here may be added by
the DHCPv6 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 |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Option-Code
OPTION_ANI_AP_BSSID (<IANA-10>).
Option-Len
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-Identifier 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-Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_OPERATOR_ID (<IANA-11>).
Option-Len
4.
Operator-Identifier
The contents of this field is the same as the DHCPv4 Operator-
Identifier Sub-option field described in Section 4.4.1.
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 .
. .
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Code
OPTION_ANI_OPERATOR_REALM (<IANA-12>).
Option-Len
The length of the Operator Realm field.
Operator-Realm
The contents of this field is the same as the Operator-Realm field
described in Section 4.4.2.
6. 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] for providing information about the access network over
which DHCP messages from the client is received.
The DHCPv4 Relay Agent when including any of these sub-options in the
DHCP message, DHCPv4 Network Name Sub-option (Section 4.3.1), DHCPv4
Access-Point Name Sub-option (Section 4.3.2), DHCPv4 Access-Point
BSSID Sub-option (Section 4.3.3), MUST include the DHCPv4 Access-
Technology-Type Sub-option (Section 4.2)
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.
The DHCPv6 Relay Agent when including any of these options in the
DHCP message, DHCPv6 Network Name Option (Section 5.2.1), DHCPv6
Access-Point Name Option (Section 5.2.2), DHCPv6 Access-Point BSSID
Option (Section 5.2.3), MUST include the DHCPv6 Access-Technology-
Type Option (Section 5.1)
7. Server Behavior
DHCPv4 base specification [RFC2131] requires that the DHCPv4 server
ignore the DHCPv4 Access Network Identifier option if it does not
understand the option.
If the DHCPv4 server does not understand the received sub-option
defined in sections 4.1 through 4.4 in the DHCPv4 Relay Agent
Information option (82) it MUST ignore those sub-options only. If
DHCPv4 Server is able to process the DHCPv4 Access Network Identifier
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sub-options defined in sections 4.1 through 4.4 received in DHCPv4
Relay Agent Information option, it MAY use this information obtained
from the sub-option for address pool selection, or for policy
decisions as per its configured policy. This information obtained
from the sub-option SHOULD NOT be stored unless it is absolutely
needed, However, if it is stored, the information MUST be deleted as
quickly as possible to eliminate any possibility of the information
getting exposed to an intruder.
If the received DHCPv4 message does not include DHCPv4 Access-
Technology-Type Sub-option (Section 4.2), but if it includes any one
of these other options, DHCPv4 Network Name Sub-option
(Section 4.3.1), DHCPv4 Access-Point Name Sub-option (Section 4.3.2),
or DHCPv4 Access-Point BSSID Sub-option (Section 4.3.3), then the
DHCPv4 server MUST ignore the received DHCPv4 Access-Network-
Identifier option and process the rest of the message as per the base
DHCPv4 specifications
DHCPv6 base specification [RFC3315] requires that the DHCPv6 server
ignore the DHCPv6 Access-Network-Identifier option if it does not
understand the option.
If the DHCPv6 server receives the options defined in Section 5 and is
configured to 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) based on its configured policy.
The server MAY use received ANI options for its address pool
selection policy decisions as per its configured policy. This
information obtained from the options SHOULD NOT be stored unless it
is absolutely needed, However, if it is stored, the information MUST
be deleted as quickly as possible to eliminate any possibility of the
information getting exposed to an intruder.
If the received DHCPv6 message does not include DHCPv6 Access-
Technology-Type Option (Section 5.1), but it includes any one of
these other options, DHCPv6 Network Name Option (Section 5.2.1),
DHCPv6 Access-Point Name Option (Section 5.2.2), or DHCPv6 Access-
Point BSSID Option (Section 5.2.3), then the DHCPv6 server MUST
ignore the received DHCPv6 Access-Network-Identifier option and
process the rest of the message as per the base DHCPv6
specifications.
8. IANA Considerations
IANA is requested to assign Sub-option codes for the following DHCPv4
Sub-options from the "DHCP Relay Agent Sub-Option Codes" registry,
<http://www.iana.org/assignments/bootp-dhcp-parameters>:
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+=================+=======================================+
| 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
<http://www.iana.org/assignments/dhcpv6-parameters>, 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 |
+=========================================================+
9. Security Considerations
Since there is no privacy protection for DHCP messages, an
eavesdropper who can monitor the link between the DHCP server and
relay agent can discover access network information.
[RFC3118] and [RFC3315] describe many of the threats in using DHCP.
[RFC3118] and [RFC3315] each provide a solution, the Authentication
Option for DHCPv4 and DHCPv6 (respectively). However, neither of
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these options are in active use and therefore are not a viable
mitigation option. DHCP itself is inherently insecure and thus link-
layer confidentiality and integrity protection SHOULD be employed to
reduce the risk of disclosure and tampering.
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
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. Administrators SHOULD
configure DHCP servers that use this option to communicate with their
relay agents using IPsec, as described in Section 21.1 of [RFC3315].
The information elements that this draft is exposing is the client's
access-network information. These pertain to the access network to
which the client is attached, such as Access Technology Type (Ex:
WLAN, Ethernet...etc), Access Point Identity (Name, BSSID), Operator
Id/Realm. In deployments where this information cannot be secured
using IPsec [RFC4301] or other security protocols, administrators
SHOULD disable the capability specified in this document on the DHCP
entities.
10. Acknowledgments
The authors would like to thank Kim Kinnear, Ted Lemon, Gaurav
Halwasia, Hidetoshi Yokota, Sheng Jiang and Francis Dupont for their
valuable inputs. And, to Tomek Mrugalski for a thorough review of
the document.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, DOI 10.17487/RFC2131, March 1997,
<http://www.rfc-editor.org/info/rfc2131>.
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[RFC3046] Patrick, M., "DHCP Relay Agent Information Option",
RFC 3046, DOI 10.17487/RFC3046, January 2001,
<http://www.rfc-editor.org/info/rfc3046>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315,
July 2003, <http://www.rfc-editor.org/info/rfc3315>.
11.2. 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.
[RFC3118] Droms, R. and W. Arbaugh., Ed., "Authentication for DHCP
Messages", RFC 3118, DOI 10.17487/RFC3118, June 2001,
<http://www.rfc-editor.org/info/rfc3118>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629,
November 2003, <http://www.rfc-editor.org/info/rfc3629>.
[RFC4030] Stapp, M. and T. Lemon, "The Authentication Suboption for
the Dynamic Host Configuration Protocol (DHCP) Relay Agent
Option", RFC 4030, DOI 10.17487/RFC4030, March 2005,
<http://www.rfc-editor.org/info/rfc4030>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <http://www.rfc-editor.org/info/rfc4301>.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<http://www.rfc-editor.org/info/rfc5213>.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
<http://www.rfc-editor.org/info/rfc5844>.
[RFC6757] Gundavelli, S., Ed., Korhonen, J., Ed., Grayson, M.,
Leung, K., and R. Pazhyannur, "Access Network Identifier
(ANI) Option for Proxy Mobile IPv6", RFC 6757,
DOI 10.17487/RFC6757, October 2012,
<http://www.rfc-editor.org/info/rfc6757>.
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[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<http://www.rfc-editor.org/info/rfc6991>.
[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
Mark Grayson
Cisco Systems
11 New Square Park
Bedfont Lakes, FELTHAM TW14 8HA
England
Email: mgrayson@cisco.com
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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
Phone:
Email: jouni.nospam@gmail.com
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