Internet-Draft Li Jun Huawei Oct 15, 2005 Expires: April 15,2006 DHCP Option for CLF/NASS draft-lijun-dhc-clf-nass-option-01.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 15, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document defines a new dhcp option for Access Network Information discovery. The network terminal can get the Access Network Information,which it is attached, through this option. And the Access Network Information can be used for different purpose, such as in TISPAN NGN network the Access Network Information can be used to discover the CLF(Connectivity Session Location and Repository Function) of the NASS (Network Attachment Subsystem).This document defines the related dhcp option and option codes. Li Jun Expires April 15, 2006 [Page 1] Internet-Draft Oct 2005 1. Introduction In many cases, the Dynamic Host Configuration Protocol (DHCP) as defined in RFC 2131 is used to configure the customer premise host. For example, in TISPAN NGN functional architecture, DHCP is used to configure the TE (NGN terminal),such as DHCP option 120 is used to configure the P-CSCF address [RFC3361]. And also, more DHCP options are needed to carry other configuration parameters, such as access network information, that may contain the Access Network Identifier (ANID) or other information of the access network which the the TE attached.But the existing DHCP options do not support carrying the access network information. One of the requirement for the DHCP to carry access network information is as follows. In TISPAM NGN network, the TE need discover the access network identifier and inform the service control subsytem which access network it attached to. The NASS, Network Attachment Subsystem, in ETSI NGN Functional Architecture has the following model [NASS]: +---------------------------+ | Service Control Subsystem | | and Applications | +---------------------------+ | |e2 | +---------+ e4 +--------+ | CLF |----------------| RACS | +---------+ +--------+ / \ / \ / \ +---------+ +---------+ +---------+ +--------+ | CPECF | | NACF | | UAAF |-----| PDBF | +---------+ +---------+ +---------+ +--------+ | \ / e3 | \ / | \ / +----+ +-----+ +-----+ +---------+ | TE |---| CNG |---| ARF |-----| AMF + +----+ +-----+ +-----+ e1 +---------+ Definition: NACF: Network Access Configuration Function is responsible for the IP address allocation to the TE. It may also distribute other network configuration parameters.DHCP servers are typical implementations of the NACF. AMF: Access Management Function translates network access requests issued by the TE. It forwards the requests for allocation of an IP address and possibly additional network configuration parameters to/from the NACF. Li Jun Expires April 15, 2006 [Page 2] Internet-Draft Oct 2005 CLF: Connectivity Session Location and Repository Function registers the association between the IP address allocated to the TE and related network location information provided by the NACF. And the CLF responds to location queries from service control subsystems and applications. UAAF: User Access Authorization Function performs user authentication, as well as authorisation checking, based on user profiles, for network access. PDBF: Profile Data Base Function CPECF: CPE Configuration Function In this architecture, a Service Control Subsystem may serve serveral access networks. The Service Control Subsystem need to communicate with the NASS of access network. The contact point of NASS is CLF. So the NACF should be able to provide to the TE an access network identifier. This information uniquely identifies the access network to which the TE is attached. When the TE accesses or registers to the Service Control Subsystem,it will carry the access network identifier obtained from NACF. With this information the Service Control system should be able to locate the CLF of NASS. The transport of the access identifier depends on extension in existing DHCP protocols. This memo is an effort to define the DHCP option to carry the access network information, such as access network identifier (ANID) and CLF identifier (CLFID). 2. Terminology The keywords "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. 3. Access Network Information Option This section defines the configuration option for the access network information.The new option is organized as a single DHCP option that contains one or more "sub-options".The initial sub-options are defined for TISPAN NGN architecture and general purpose. These include a "ANID" sub-option for access network identifier,and a "CLFID" sub-option for TISPAN CLF identifier. The format of the access network information option is: Code Len Access network Information Field +------+------+------+------+------+------+--...-+------+ | TBD | N | i1 | i2 | i3 | i4 | | iN | +------+------+------+------+------+------+--...-+------+ The length N gives the total number of octets in the Access Network Information Field. The Access Network Information field consists of a sequence of SubOpt/Length/Value tuples for each sub-option, encoded in the following manner: Li Jun Expires April 15, 2006 [Page 3] Internet-Draft Oct 2005 SubOpt Len Sub-option Value +------+------+------+------+------+------+--...-+------+ | 1 | N | i1 | i2 | i3 | i4 | | iN | +------+------+------+------+------+------+--...-+------+ SubOpt Len Sub-option Value +------+------+------+------+------+------+--...-+------+ | 2 | N | i1 | i2 | i3 | i4 | | iN | +------+------+------+------+------+------+--...-+------+ The initial assignment of Access Network Information Sub-options is as follows: Access Network Information Sub-Option Description Sub-option Code --------------- ---------------------- 1 Access Network ID Sub-option 2 CLF ID Sub-option Notes: Generally, Access Network Identifier is suffice to indicate the attached access network. But in some case, more infomations of the access network may be required by some services or applications. So more sub-option need to be defined to carry this informations. Such as in TISPAN NGN architecture, the service control subsystem may want to get the CLF address from TE directly, so a CLFID sub-option is defined. 3.1 Access Network ID Sub-option The ANID sub-option contains a character string indicating the Access Network. The ANID sub-option has the following format: SubOpt Len Access Netwok ID +------+------+------+------+------+------+------+------+-- | 1 | n | c1 | c2 | c3 | c4 | c5 | c6 | ... +------+------+------+------+------+------+------+------+-- An example case when the access network is "China-telecom-001" will be: +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 1 |17 |'c'|'h'|'i'|'n'|'a'|'-'|'t'|'e'|'l'|'e'|'c'|'o'|'m'|'-'| +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+ |'0'|'0'|'1'| +---+---+---+ 3.2 CLF ID Sub-option The CLFID sub-option contains the CLF indentifier, which may be one or more IPV4 addresss or domain names of the CLF. The coding of the CLFID is out of scope the draft. Li Jun Expires April 15, 2006 [Page 4] Internet-Draft Oct 2005 4. IANA Considerations The option code for this dhcp option MUST be assigned by IANA. 5 Normative References [NASS] Draft ETSI ES 02021 V1.0.0 NGN Functional Architecture, Network Attachment Subsystem, Release 1 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC3361] Schulzrinne, "DHCPv4 Option for SIP Servers", RFC 3361, August 2002. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. 6 Author's Address Li Jun Huawei Industrial Base Bantian Longgang Shenzhen 518129 P.R.C EMail: Leejun@huawei.com Fax: +86-755-28972045 Phone: +86-13823734043 7 Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 8 Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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