Internet DRAFT - draft-lijun-dhc-clf-nass-option
draft-lijun-dhc-clf-nass-option
Internet-Draft Li Jun
<draft-lijun-dhc-clf-nass-option-01.txt> 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
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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.
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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.
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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:
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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.
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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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