Network Working GroupInternet Engineering Task Force (IETF) S. BhandariInternet-DraftRequest for Comments: 7839 S. GundavelliIntended status:Category: Standards Track M. GraysonExpires: August 4, 2016ISSN: 2070-1721 B. Volz Cisco Systems J. Korhonen BroadcomCommunications February 01,Limited June 2016Access Network IdentifierAccess-Network-Identifier Option in DHCPdraft-ietf-dhc-access-network-identifier-13Abstract This document specifies the format and mechanism that is to be used for encodingaccess network identifiersAccess-Network Identifiers in DHCPv4 and DHCPv6 messages by defining newaccess network identifierAccess-Network-Identifier options and sub-options. Status ofthisThis Memo ThisInternet-Draftissubmitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documentsan Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF).Note that other groups may also distribute working documents as Internet-Drafts. The listIt represents the consensus ofcurrent Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents validthe IETF community. It has received public review and has been approved fora maximumpublication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status ofsix monthsthis document, any errata, and how to provide feedback on it may beupdated, replaced, or obsoleted by other documentsobtained atany 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.http://www.rfc-editor.org/info/rfc7839. 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 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 . . . . . . . . . . . . . . . . . . . . . . . .. 32 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. DHCPv4Network NameNetwork-Name Sub-option . . . . . . . . . . ..7 4.3.2. DHCPv4Access-Point NameAccess-Point-Name Sub-option . . . . . . . . . 8 4.3.3. DHCPv4Access-Point BSSIDAccess-Point-BSSID Sub-option . . . . . . . .. 98 4.4. DHCPv4Operator IdentifierOperator-Identifier Sub-options . . . . . . . . ..9 4.4.1. DHCPv4 Operator-Identifier Sub-option . . . . . . . . 9 4.4.2. DHCPv4 Operator-Realm Sub-option . . . . . . . . . .. 109 5. DHCPv6 Access-Network-Identifier Options . . . . . . . . . ..10 5.1. DHCPv6 Access-Technology-Type Option . . . . . . . . . .. 1110 5.2. DHCPv6 Network-Identifier Options . . . . . . . . . . . . 11 5.2.1. DHCPv6Network NameNetwork-Name Option . . . . . . . . . . . . ..11 5.2.2. DHCPv6Access-Point NameAccess-Point-Name Option . . . . . . . . . . .1211 5.2.3. DHCPv6Access-Point BSSIDAccess-Point-BSSID Option . . . . . . . . . ..12 5.3. DHCPv6Operator IdentifierOperator-Identifier Options . . . . . . . . . . .. 1312 5.3.1. DHCPv6 Operator-Identifier Option . . . . . . . . . .1312 5.3.2. DHCPv6 Operator-Realm Option . . . . . . . . . . . ..13 6. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . .. 1413 7. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 14 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 10.Acknowledgments . .References . . . . . . . . . . . . . . . . . . . . .17 11. References. . . . 17 10.1. Normative References . . . . . . . . . . . . . . . . . . 17 10.2. Informative References . . . .17 11.1. Normative References. . . . . . . . . . . . . 17 Acknowledgements . . . . . .17 11.2. Informative References. . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .. 1918 1. IntroductionAccess networkAccess-network identification(ANI)of a network device has a range of applications. Forexampleexample, thelocal mobility anchorLocal Mobility Anchor (LMA) in a Proxy Mobile IPv6 (PMIPv6) domain is able to provideaccess network and access operator specific handling or policing ofservice treatment for the mobilenodenode's trafficusing information aboutbased on the access network to which the mobile node is attached. This document specifies the Dynamic Host Configuration Protocol for IPv4 (DHCPv4) [RFC2131] and the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315] options foraccess networkaccess-network identification that is added byRelaythe relay agent in the DHCPv4 or DHCPv6 messages sent towards theServer.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 functionsDynamic Host Configuration Protocol (DHCP)A DHCP relay agent that is aware of the access network and access operatoraddadds 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. MotivationProxy mobile IPv6PMIPv6 [RFC5213] can be used for supporting network-based mobility management in various types of network deployments. The network architectures, such asServiceservice provider Wi-Fi access aggregationor,or WLAN integrated mobile packetcorecore, are examples whereProxy Mobile IPv6PMIPv6 is a component of the overall architecture. Some of these architectures require the ability of thelocal mobility anchor (LMA)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 mobilityarchitecturesarchitectures, such asPCCPolicy and Charging Control (PCC) [TS23203] andANDSFAccess Network Discovery and Selection Function (ANDSF) [TS23402] in the 3GPPsystemsystem, allow configuration of policy rules with conditions based on theaccess networkaccess-network information. For example, the service treatment for the mobile node's traffic may be different when they are attached toaan access network owned by the home operator than when owned by a roaming partner.The service treatment can also beIn the case of access networks based on IEEE 802.11, the service treatment can also be different based on the configured Service Set Identifiers(SSID) in case of IEEE 802.11 based access networks.(SSIDs). 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 carryaccess network identifiersAccess-Network Identifiers in PMIPv6 signaling from the Mobile Access Gateway (MAG) to the LMA. The MAG can learn this information from the DHCP options as inserted by the DHCPRelayrelay agentbefore MAG.in the access network. If the MAG relays the DHCP messages to the LMA as specified in[RFC5844][RFC5844], this information can be inserted by the MAG towards the LMA in the forwarded DHCP messages. Figure1,1 illustrates an exampleProxy Mobile IPv6of PMIPv6 deployment. In this example, the access network is based on IEEE 802.11based access-network,technology, the DHCPRelay Agentrelay agent function is located on theaccess pointAccess Point (AP), and the DHCPServerserver function is located on the MAG. The MAG delivers the information elements related to the access network to the LMA overProxy Mobile IPv6PMIPv6 signaling messages. The MAG obtains these information elements from the DHCPRelay Agentrelay agent as per this specification. Theinformationalinformation elements related to the access network include the SSID of the used IEEE 802.11 network, thegeo- locationgeo-location of theaccess-networkaccess network to which the mobile node is attached, and the identity of the operator running the IEEE 802.11access networkaccess-network infrastructure. SSID: IETF-1Operator-Id:Operator-Identifier: provider1.example +--+ |AP|-----------.{Access Specific{Access-Specific Policies) +--+ | (DHCP Server) _-----_ | (DHCP Relay) +-----+ _( )_ +-----+ | MAG |-=========( PMIPv6 )======-| LMA |- +-----+ (_ Tunnel_) +-----+ +--+ | '-----' |AP|-----------' +--+ (DHCP Relay) SSID: IETF-2Operator-Id:Operator-Identifier: provider2.example Access NetworksattachedAttached 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 theDHCP relatedDHCP-related terms used in this document are to be interpreted as defined inthe Dynamic Host Configuration Protocol (DHCPv4)DHCPv4 [RFC2131] andDynamic Host Configuration Protocol for IPv6 (DHCPv6)DHCPv6 [RFC3315] specifications.DHCP message"DHCP message" refers to both DHCPv4 and DHCPv6 messages throughout this document. All themobility relatedmobility-related terms used in this document are to be interpreted as defined in theProxy Mobile IPv6PMIPv6 specifications [RFC5213] and [RFC5844]. Additionally, this document uses the following abbreviations: Service Set Identifier (SSID) The Service Set Identifier (SSID) identifies the name of the IEEE 802.11 network. The 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 theaccess-networkaccess network where the client is attached. 4. DHCPv4 Access-Network-Identifier Option TheAccess NetworkAccess-Network Identifier (ANI) carries information related toidentifythe identity of the access network to which the client is attached. This information includesaccess technologyaccess-technology type, network identifier, andaccess-access network operator identifiers. Relay agents that includeAccess Network IdentifierANI information include one or moresub-optionssub- options (see Section 4.1) in the Relay Agent Information option [RFC3046]. 4.1. DHCPv4 Access-Network-Identifier Sub-options Theaccess network identifierAccess-Network-Identifier information will be defined in multiplesub-options,sub-options allocated from theDHCP"DHCP Relay Agent Sub-OptionCodes.Codes" registry. ANI Sub-options: The ANISub-options consistssub-options consist of a sequence of Sub- Option Code, Length, and Value tuples for each sub-option, encoded in the following manner:SubOptSubopt 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 the DHCPaccess network identifier sub-optionsAccess-Network-Identifier sub- options is as follows: +=================+=======================================+ | SUB-OPTION CODE | SUB-OPTION DESCRIPTION | +=================+=======================================+ |<IANA-1>13 |Access Technology TypeAccess-Technology-Type Sub-option | +=========================================================+ |<IANA-2>14 |Access Network NameAccess-Network-Name Sub-option | +=========================================================+ |<IANA-3>15 |Access Point NameAccess-Point-Name Sub-option | +=========================================================+ |<IANA-4>16 |Access Point BSSIDAccess-Point-BSSID Sub-option | +=========================================================+ |<IANA-5>17 | Operator-Identifier Sub-option | +=========================================================+ |<IANA-6>18 | 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<IANA-1>.13 Length2.2 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 spaceAccess"Access Technology Type Option typevaluevalues" 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.,aan SSID in the case of an IEEE 802.11Access Network,access network orPLMNa Public Land-based Mobile Network (PLMN) Identifier [TS23003] in the case of a 3GPPaccess)access network) andAccess Point namethe Access-Point Name to which the client is attached. The format of these sub-options is defined in the following sections. The Network-Identifier sub-options are only for the currently knownaccess technologyaccess-technology types. 4.3.1. DHCPv4Network NameNetwork-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 NameNetwork-Name (e.g., SSID or PLMNID) . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Subopt Code<IANA-2>.14 Length The length of theNetwork NameNetwork-Name field.Network NameNetwork-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 theNetwork NameNetwork-Name is dependent on the access technology to which the mobile node is attached. ForIEEE 802.11networks basednetworks,on IEEE 802.11, thenetwork nameNetwork-Name will be the SSID of the network. For 3GPPaccess basedaccess-based networks, it is the PLMN Identifier of the accessnetworknetwork, and for 3GPP2 access, theNetwork NameNetwork-Name is theAccess Network Identifier[ANI].ANI [ANI]. When encoding the PLMN Identifier, both the Mobile Network Code (MNC) [TS23003] and Mobile Country Code (MCC) [TS23003] MUST be3three digits. If the MNC in use only has2two digits, then it MUST be preceded with a '0'. 4.3.2. DHCPv4Access-Point NameAccess-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 NameAccess-Point-Name . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Subopt Code<IANA-3>.15 Length The length of theAccess-Point NameAccess-Point-Name field.Access-Point NameAccess-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. WhileNetwork Namethe Network-Name (e.g., SSID) identifies the operator's access network,Access-Point Namethe Access-Point-Name identifies a specific network device in the network to which the mobile node is attached. In some deployments, theAccess-PointAccess-Point- Name can be set to the string representation of the Media Access Control (MAC) address of the device as specified in [RFC6991] (see mac-addressstring type of the devicetypedef) 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. DHCPv4Access-Point BSSIDAccess-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 BSSIDAccess-Point-BSSID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Subopt Code<IANA-4>.16 Length6. Access-Point BSSID6 Access-Point-BSSID The 48-bit BasicService Set IdentificationSSSID (BSSID) of the access point to which the mobile node is attached. 4.4. DHCPv4Operator IdentifierOperator-Identifier Sub-options TheOperator identifierOperator-Identifier sub-options can be used for carrying theoperator identifiersOperator-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>.17 Length4.4 Operator-Identifier The Operator-Identifierasis a variable-length Private Enterprise Number (PEN) [SMI] encoded in anetwork-bytenetwork byte order. Please refer to(sectionSection 3.1.3 of[RFC6757])[RFC6757] for additional details. 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>.18 Length The length of theOperator RealmOperator-Realm field. Operator-Realm Realm of the operator (e.g., EXAMPLE.COM). Please refer to(sectionSection 3.1.3 of[RFC6757])[RFC6757] for additional details. 5. DHCPv6 Access-Network-Identifier Options TheAccess Network IdentifierAccess-Network-Identifier options defined here may be added by the DHCPv6Relayrelay agent in Relay-forward messages. +=================+=======================================+ | OPTION CODE | OPTION DESCRIPTION | +=================+=======================================+ |<IANA-7>105 | OPTION_ANI_ATT | +=========================================================+ |<IANA-8>106 | OPTION_ANI_NETWORK_NAME | +=========================================================+ |<IANA-9>107 | OPTION_ANI_AP_NAME | +=========================================================+ |<IANA-10>108 | OPTION_ANI_AP_BSSID | +=========================================================+ |<IANA-11>109 | OPTION_ANI_OPERATOR_ID | +=========================================================+ |<IANA-12>110 | OPTION_ANI_OPERATOR_REALM | +=========================================================+ 5.1. DHCPv6 Access-Technology-Type Option This option is used for exchanging the type oftheaccess technology the clientis attacheduses to attach 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>).(105) Option-Len2.2 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 TypeAccess-Technology-Type (ATT): The contents of this fieldisare 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.,aan SSID in the case of an IEEE 802.11Access Network,access network or a PLMN Identifier [TS23003] in the case of a 3GPPaccess)access network) andAccess Point namean Access-Point Name to which the client is attached. The format of these options is defined below. 5.2.1. DHCPv6Network NameNetwork-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 NameNetwork-Name (e.g., SSID or PLMNID) . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-Code OPTION_ANI_NETWORK_NAME(<IANA-8>).(106) Option-Len The length of theNetwork NameNetwork-Name field.Network NameNetwork-Name The contents of this fieldisare the same as theNetwork NameNetwork-Name field described in Section 4.3.1. 5.2.2. DHCPv6Access-Point NameAccess-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 NameAccess-Point-Name . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-Code OPTION_ANI_AP_NAME(<IANA-9>).(107) Option-Len The length of theAccess-Point NameAccess-Point-Name field.Access-Point NameAccess-Point-Name The contents of this fieldisare the same as theAccess-Point NameAccess-Point-Name field described in Section 4.3.2. 5.2.3. DHCPv6Access-Point BSSIDAccess-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 BSSIDAccess-Point-BSSID | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-Code OPTION_ANI_AP_BSSID(<IANA-10>).(108) Option-Len6. Access-Point BSSID6 Access-Point-BSSID The contents of this fieldisare the same as theAccess-Point BSSIDAccess-Point-BSSID field described in Section 4.3.3. 5.3. DHCPv6Operator IdentifierOperator-Identifier Options TheOperator IdentifierOperator-Identifier options can be used for carrying theoperator identifierOperator-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>).(109) Option-Len4.4 Operator-Identifier The contents of this fieldisare 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 . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-Code OPTION_ANI_OPERATOR_REALM(<IANA-12>).(110) Option-Len The length of theOperator RealmOperator-Realm field. Operator-Realm The contents of this fieldisare the same as the Operator-Realm field described in Section 4.4.2. 6. Relay Agent Behavior DHCPv4Relay Agentsrelay agents MAY include sub-options as defined insectionSection 4.2 through 4.4 of [RFC3046] in the Relay Agent Information optionas defined in [RFC3046]for providing information about the access network over which DHCP messages from the clientisare received. The DHCPv4Relay Agentrelay agent MUST include the DHCPv4 Access-Technology-Type Sub-option (Section 4.2) when including any of these sub-options in the DHCPmessage,message: DHCPv4Network NameNetwork-Name Sub-option (Section 4.3.1), DHCPv4Access-Point NameAccess-Point-Name Sub-option (Section 4.3.2), and DHCPv4Access-Point BSSID Sub-option (Section 4.3.3), MUST include the DHCPv4 Access- Technology-TypeAccess-Point-BSSID Sub-option (Section4.2)4.3.3). DHCPv6 Relay Agents MAY include optionsdefined(defined in Section55) in the 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 clientisare received. The DHCPv6Relay Agentrelay agent MUST include the DHCPv6 Access-Technology-Type Option (Section 5.1) when including any of these options in the DHCPmessage,message: DHCPv6Network NameNetwork-Name Option (Section 5.2.1), DHCPv6Access-Point NameAccess- Point-Name Option (Section 5.2.2), and DHCPv6Access-Point BSSID Option (Section 5.2.3), MUST include the DHCPv6 Access-Technology- TypeAccess-Point-BSSID Option (Section5.1)5.2.3). 7. Server Behavior The DHCPv4 base specification [RFC2131] requires that the DHCPv4 server ignore the DHCPv4Access Network Identifier optionAccess-Network-Identifier Option if it does not understand the option. If the DHCPv4 server does not understand the received sub-option defined insectionsSections 4.1 through 4.4inof [RFC3046], the DHCPv4Relay Agent Information option (82)Relay- Agent-Information Option, it MUST ignore those sub-options only. If the DHCPv4Serverserver is able to process the DHCPv4Access NetworkAccess-Network- Identifier sub-options defined insectionsSections 4.1 through 4.4received inof [RFC3046], the DHCPv4Relay Agent Information option,Relay-Agent-Information Option, it MAY use this information obtained from the sub-option for address poolselection,selection or for policy decisions as per its configured policy. This information obtained from the sub-option SHOULD NOT be stored unless it is absolutelyneeded,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.IfThe DHCPv4 server MUST ignore the received DHCPv4 Access-Network- Identifier Option and process the rest of the message as per the base DHCPv4 specifications if the received DHCPv4 message does not include the DHCPv4Access- Technology-TypeAccess-Technology-Type Sub-option (Section4.2),4.2) butif it includesdoes include any one of these otheroptions,options: DHCPv4 Network NameSub-optionSub- option (Section 4.3.1), DHCPv4Access-Point NameAccess-Point-Name Sub-option (Section 4.3.2), or DHCPv4Access-Point BSSIDAccess-Point-BSSID Sub-option (Section4.3.3), 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 specifications4.3.3). DHCPv6 base specification [RFC3315] requires that the DHCPv6 server ignore the DHCPv6 Access-Network-IdentifieroptionOption 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 DHCPv6Access Network identifierAccess-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 absolutelyneeded,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.IfThe DHCPv6 server MUST ignore the received DHCPv6 Access-Network- Identifier Option and process the rest of the message as per the base DHCPv6 specifications if the received DHCPv6 message does not include the DHCPv6Access- Technology-TypeAccess-Technology-Type Option (Section5.1),5.1) but it does includes any one of these otheroptions,options: DHCPv6Network NameNetwork-Name Option (Section 5.2.1), DHCPv6Access-Point NameAccess-Point-Name Option (Section 5.2.2), or DHCPv6Access- Point BSSIDAccess-Point-BSSID Option (Section5.2.3), 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.5.2.3). 8. IANA Considerations IANAis requested to assign Sub-optionhas assigned sub-option codes for the following DHCPv4Sub-optionssub- options from the "DHCP Relay Agent Sub-Option Codes" registry, <http://www.iana.org/assignments/bootp-dhcp-parameters>: +=================+=======================================+ | SUB-OPTION CODE | SUB-OPTION DESCRIPTION | +=================+=======================================+ |<IANA-1>13 |Access Technology TypeAccess-Technology-Type Sub-option | +=========================================================+ |<IANA-2>14 |Access Network NameAccess-Network-Name Sub-option | +=========================================================+ |<IANA-3>15 |Access Point NameAccess-Point-Name Sub-option | +=========================================================+ |<IANA-4>16 |Access Point BSSIDAccess-Point-BSSID Sub-option | +=========================================================+ |<IANA-5>17 |Operator IdentifierOperator-Identifier Sub-option | +=========================================================+ |<IANA-6>18 |Operator RealmOperator-Realm Sub-option | +=========================================================+ IANAis requested to assignhas assigned option codes for the following DHCPv6 options from the "OptionCodesCodes" registry forDHCPv6" registryDHCPv6, <http://www.iana.org/assignments/dhcpv6-parameters>, as specified in [RFC3315]: +=================+=======================================+ | OPTION CODE | OPTION DESCRIPTION | +=================+=======================================+ |<IANA-7>105 | OPTION_ANI_ATT | +=========================================================+ |<IANA-8>106 | OPTION_ANI_NETWORK_NAME | +=========================================================+ |<IANA-9>107 | OPTION_ANI_AP_NAME | +=========================================================+ |<IANA-10>108 | OPTION_ANI_AP_BSSID | +=========================================================+ |<IANA-11>109 | OPTION_ANI_OPERATOR_ID | +=========================================================+ |<IANA-12>110 | 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 discoveraccess networkaccess-network information. [RFC3118] and [RFC3315] describe many of the threats in using DHCP. [RFC3118] and [RFC3315] each provide asolution,solution; the Authentication Option for DHCPv4 and DHCPv6 (respectively). However, neither of 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 incorrectaccess network identifierAccess-Network-Identifier options for malicious purposes. A DHCP client can also pose as a rogue DHCP relay agent by sending incorrectaccess network identifierAccess-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 the DHCPv4relay agent information optionRelay-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 thisdraftdocument is exposingisare the client's access-network information. These pertain to the access network to which the client is attached, such asAccess TechnologyAccess-Technology Type(Ex:(e.g., WLAN,Ethernet...etc), Access PointEthernet, etc.), Access-Point Identity (Name, BSSID),Operator Id/Realm.and Operator-Identifier and Operator-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.References11.1.10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI10.17487/ RFC2119,10.17487/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>. [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>.11.2.10.2. Informative References [ANI] "Interoperability Specification (IOS) for High Rate Packet Data (HRPD) Radio Access Network Interfaces with Session Control in the AccessNetwork, A.S0008-A v3.0", October 2008.Network", 3GPP2 A.S0008-C v4.0, April 2011, <http://www.3gpp2.org/public_html/specs/A00-20 110419-002Er0%20A.S0008-C%20v4.0%20HRPD%20IO\S-Pub_2011051 3.pdf>. [RFC3118] Droms,R.R., Ed. and W.Arbaugh.,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>. [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, <http://www.rfc-editor.org/info/rfc6991>. [SMI] IANA, "PRIVATE ENTERPRISE NUMBERS, SMI Network Management Private Enterprise Codes",February 2011.March 2016, <https://www.iana.org/assignments/enterprise-numbers>. [TS23003] 3GPP, "Numbering, addressing and identification",2011.3GPP TS 23.003 13.4.0, December 2015. [TS23203] 3GPP, "Policy andCharging Control Architecture", 2012.charging control architecture", 3GPP TS 23.203 13.6.0, December 2015. [TS23402] 3GPP, "Architecture enhancements for non-3GPP accesses",2012.3GPP TS 23.402 13.4.0, December 2015. Acknowledgements The authors would like to thank Kim Kinnear, Ted Lemon, Gaurav Halwasia, Hidetoshi Yokota, Sheng Jiang, and Francis Dupont for their valuable input. Also, thank you to Tomek Mrugalski for a thorough review of the document. 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 95134USAUnited States Email: sgundave@cisco.com Mark Grayson Cisco Systems 11 New Square Park Bedfont Lakes, FELTHAM TW14 8HA England Email: mgrayson@cisco.com Bernie Volz Cisco Systems 1414 Massachusetts AveBoxborough,,Boxborough, MA 01719USAUnited States Email: volz@cisco.com Jouni Korhonen BroadcomCommunications Porkkalankatu 24 FIN-00180 Helsinki, Finland Phone:Limited 3151 Zanker Rd San Jose, CA 95134 United States Email: jouni.nospam@gmail.com