Network Working Group S. Bhandari Internet-Draft S. Gundavelli Intended status: Standards Track Cisco Systems Expires: April 30, 2015 J. Korhonen Renesas Mobile M. Grayson Cisco Systems October 27, 2014 Access Network Identifier Option in DHCP draft-ietf-dhc-access-network-identifier-04 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 April 30, 2015. Copyright Notice Copyright (c) 2014 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 Bhandari, et al. Expires April 30, 2015 [Page 1] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 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 . . . . . . . . . 9 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 . . . . . . . . . . . 10 5. DHCPv6 Access-Network-Identifier options . . . . . . . . . . . 10 5.1. DHCPv6 Access-Network-Type option . . . . . . . . . . . . 11 5.2. DHCPv6 Network-Identifier options . . . . . . . . . . . . 12 5.2.1. DHCPv6 Network Name option . . . . . . . . . . . . . . 12 5.2.2. DHCPv6 Access-Point Name option . . . . . . . . . . . 12 5.2.3. DHCPv6 Access-Point BSSID option . . . . . . . . . . . 13 5.3. Operator identifier options . . . . . . . . . . . . . . . 13 5.3.1. Operator Enterprise ID option . . . . . . . . . . . . 13 5.3.2. Operator Realm option . . . . . . . . . . . . . . . . 14 6. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 15 7. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . 15 8. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 15 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 10. Security Considerations . . . . . . . . . . . . . . . . . . . 17 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 12.1. Normative References . . . . . . . . . . . . . . . . . . . 18 12.2. Informative References . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Bhandari, et al. Expires April 30, 2015 [Page 2] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 1. Introduction Access network identification 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 v4 (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 Bhandari, et al. Expires April 30, 2015 [Page 3] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 DHCP options as inserted by DHCP client or 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 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 Service Set Identifier (SSID) Bhandari, et al. Expires April 30, 2015 [Page 4] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 Service Set Identifier Service Set Identifier (SSID) identifies the name of the IEEE 802.11 network. SSID differentiates from one network to the other. 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 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 (8-bits) 8-bit code carrying Access Network Identifier sub-options, Added by client: OPTION_ACCESS_NETWORK_ID To be assigned by IANA. len (8-bits) Total length of the included sub-options Client inserts Access Network Identifier option that contains one or more suboptions, as defined in Section 4.1. Relay agent that wants to include Access Network Indentifer information includes one or more sub-options (see Section 4.1) in Relay Agent Information option [RFC3046]. 4.1. DHCPv4 Access-Network-Identifier sub-options Access network identifier information will be defined in multiple sub-options. Bhandari, et al. Expires April 30, 2015 [Page 5] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 ANI Sub-options: The ANI Sub-options consists of a sequence of SubOptCode/Length/Value tuples for each sub-option, encoded in the following manner: SubOpt Len Sub-option Value +------+------+------+------+------+------+--...-+------+ | code | N | s1 | s2 | s3 | s4 | | sN | +------+------+------+------+------+------+--...-+------+ ANI Sub-options are defined in following sections. (postamble) The initial assignment of DHCP access network identifier Sub-options is as follows: +================+========================================+ | SUBOPTION CODE | SUBOPTION DESCRIPTION | +================+========================================+ | | Access Technology Type Suboption | +=========================================================+ | | Access Network Name Suboption | +=========================================================+ | | Access Point Name Suboption | +=========================================================+ | | Access Point BSSID Sub-option | +=========================================================+ | | Operator-Identifier Sub-option | +=========================================================+ | | 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 Bhandari, et al. Expires April 30, 2015 [Page 6] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | suboption-code| Length | ATT | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ suboption code (8 bits) 8-bit code, it should be set to value of ;, indicating that its a Access-Network-Type sub-option. Length (1 octet) 8-bit unsigned integer indicating the length of this suboption in octets, excluding the suboption-code and length fields. This field must be set to a value of (1). Access-Technology-Type (ATT) An 8-bit field that specifies the access technology through which the client is connected to the access link. The values is as populated 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |SubOption Code | Length | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Name (e.g., SSID or PLMNID) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SubOption Code (8 bits) 8-bit code, it should be set to value of , indicating that its a Network-Name sub-option Length (8-bits) 8-bit indicating Total length of this sub option, excluding the suboption code and length fields. The value can be in the range of 2 to 32 octets. Bhandari, et al. Expires April 30, 2015 [Page 7] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 Network Name (Variable Length) The name of the access network to which the mobile node is attached. 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 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'. Encoding MUST be UTF-8. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |suboption code | Length | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access-Point Name ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ subOption code (8 bits) 8-bit code, it should be set to value of , indicating that its a Access-Point Name sub-option Length (1 octet) 8-bit indicating Total length of this sub option, excluding the suboption code and length fields. The value can be in the range of 2 to 32 octets. 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 Media Access Control (MAC) address 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 string is carried in UTF-8 representation. Bhandari, et al. Expires April 30, 2015 [Page 8] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |suboption code | Length(6) | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Access-Point BSSID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ suboption code (8 bits) 8-bit code, it should be set to value of , indicating that its a Access-Point BSSID sub-option. Length (1 octet) 8-bit indicating Total length of this sub option, excluding the suboption code and length fields. The value is set to 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SubOption Code| Length | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Operator Enterprise ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SubOption Code (1-Octet) 8 bit code, It should be set to value of , indicating that it is Operator-Identifier sub-option. Bhandari, et al. Expires April 30, 2015 [Page 9] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 Length (1-Octet) Total length of this sub option, excluding the suboption code and length fields. Operator Enterprise ID (4-Octets) Vendor ID as a four octet Private Enterprise Number [SMI]. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | suboptioncode | Length | ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Operator Realm ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SubOption Code (8 bits) 8 bit code. It should be set to value of , indicating that it is Operator-Realm sub-option. Length (1 octet) Total length of this sub option, excluding the suboption code and length fields. Operator Realm (Variable Length) 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]. Up to (253) octets of the operator realm. 5. DHCPv6 Access-Network-Identifier options The Access Network Identifier option defined here will be added by DHCPv6 client in upstream DHCPv6 messages or by the Relay in Relay- forward messages. Bhandari, et al. Expires April 30, 2015 [Page 10] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 +================+========================================+ | OPTION CODE | OPTION DESCRIPTION | +================+========================================+ | | OPTION_ANI_ATT | +=========================================================+ | | OPTION_ANI_NETWORK_NAME | +=========================================================+ | | OPTION_ANI_AP_NAME | +=========================================================+ | | OPTION_ANI_AP_BSSID | +=========================================================+ | | OPTION_ANI_OPERATOR_ID | +=========================================================+ | | OPTION_ANI_OPERATOR_REALM | +=========================================================+ 5.1. DHCPv6 Access-Network-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 Code | OptLen | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access Technology Type (ATT) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code (16-bits) 16-bit code OPTION_ANI_ATT option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option. The value must be set to (1). Access Technology Type (ATT): Content of this is same as ATT field described in Section 4.2. Bhandari, et al. Expires April 30, 2015 [Page 11] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 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-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Network Name (e.g., SSID or PLMNID) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code (16-bits) 16-bit code OPTION_ANI_NETWORK_NAME option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option.The value can be in the range of 2 to 32 octets. Network Name (Variable Length) Content of this field is same as 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-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access-Point Name ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Bhandari, et al. Expires April 30, 2015 [Page 12] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 option-code (16-bits) 16-bit code OPTION_ANI_AP_NAME option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option.The value can be in the range of 2 to 32 octets. Access-Point Name (Variable Length) Content of this field is same as described in Access-Point Name 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-code (TBD3) | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access-Point BSSID ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code (16-bits) 16-bit code OPTION_ANI_AP_BSSID option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option.The value is set to 6. Access-Point BSSID (Variable Length) Content of this field is same as described in Access-Point BSSID described in Section 4.3.3. 5.3. 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. Operator Enterprise ID option Bhandari, et al. Expires April 30, 2015 [Page 13] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 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-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Operator Enterprise ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code (16-bits) 16-bit code OPTION_ANI_OPERATOR_ID option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option. AOperator Enterprise ID Content of this is same as Operator Enterprise ID field described in Section 4.4.1. 5.3.2. 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-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Operator Realm ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ option-code (16-bits) OPTION_ANI_OPERATOR_REALM option-length (16-bits) 16-bit unsigned integer indicating length in octets of this option. Operator Realm Content of this is same as Operator Realm field described in Section 4.4.2. Bhandari, et al. Expires April 30, 2015 [Page 14] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 6. Client Behavior DHCPv4 clients MAY include 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. 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. If the DHCPv4 relay agent receives DHCPv4 message already containing access network identifier sub-options within option 82 based on its configured policy it MAY overwrite the sub-options. 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 packets 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 DHCPv4 Access Network Identifier option or in Relay Agent Information options 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 it for address pool selection policy decisions as per its configured policy. DHCPv4 server MAY store this information along with the lease for logging and audit purpose. DHCPv4 server MAY use the sub-options defined in Bhandari, et al. Expires April 30, 2015 [Page 15] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 sections 4.1 through section 4.4 inserted by the DHCPv4 client in DHCPv4 Access Network Identifier option or by DHCPv4 relay agent in Relay Agent Information option based on its configured policy. 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 DHCP message of the DHCPv6 relay agent(s) or from the DHCPv6 client based on its configured policy. 9. IANA Considerations This document defines DHCPv4 Access Network Identifier option which requires assignment of DHCPv4 option code TBD1 assigned from "BOOTP Vendor Extensions and DHCP Options" registry , 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" +================+========================================+ | SUBOPTION CODE | SUBOPTION DESCRIPTION | +================+========================================+ | | Access Technology Type Suboption | +=========================================================+ | | Access Network Name Suboption | +=========================================================+ | | Access Point Name Suboption | +=========================================================+ | | Access Point BSSID Sub-option | +=========================================================+ | | Operator-Identifier Sub-option | +=========================================================+ | | Operator-Realm Sub-option | +=========================================================+ IANA is requested to assign option codes for the following DHCPv6 options from the "Option Codes registry for DHCPv6" registry , as specified. Bhandari, et al. Expires April 30, 2015 [Page 16] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 +================+========================================+ | OPTION CODE | OPTION DESCRIPTION | +================+========================================+ | | OPTION_ANI_ATT | +=========================================================+ | | OPTION_ANI_NETWORK_NAME | +=========================================================+ | | OPTION_ANI_AP_NAME | +=========================================================+ | | OPTION_ANI_AP_BSSID | +=========================================================+ | | OPTION_ANI_OPERATOR_ID | +=========================================================+ | | 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 Bhandari, et al. Expires April 30, 2015 [Page 17] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 the DHCP relay agent is trusted, a deeper defense using the authentication suboption 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, Bernie Volz, Tomek Mrugalski, Hidetoshi Yokota and Sheng Jiang for their valuable inputs. 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. Bhandari, et al. Expires April 30, 2015 [Page 18] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 [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. [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 Bhandari, et al. Expires April 30, 2015 [Page 19] Internet-Draft ANI Options for DHCPv4 and DHCPv6 October 2014 Jouni Korhonen Renesas Mobile Linnoitustie 6 FIN-02600 Espoo, Finland Phone: Email: jouni.nospam@gmail.com Mark Grayson Cisco Systems 11 New Square Park Bedfont Lakes, FELTHAM TW14 8HA ENGLAND Email: mgrayson@cisco.com Bhandari, et al. Expires April 30, 2015 [Page 20]