Network Working Group M. Boucadair
Internet-Draft D. Binet
Intended status: Standards Track France Telecom
Expires: November 21, 2011 May 20, 2011
IPv6 RA Option for SIP Proxy Server
draft-boucadair-6man-sip-proxy-00
Abstract
This document specifies a new optional extension to IPv6 Router
Advertisement messages to allow IPv6 routers to advertise SIP Proxy
Server addresses to IPv6 hosts. The provisioning of the SIP Proxy
Server address is crucial to access SIP-based services. Means to
ensure reliable delivery of this information to connecting SIP User
Agents is a must.
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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 21, 2011.
Copyright Notice
Copyright (c) 2011 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SIP Proxy Server Option . . . . . . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Normative References . . . . . . . . . . . . . . . . . . . 5
5.2. Informative References . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
1.1. Needs
Access to sensitive SIP-based service offering relies on the
provisioning of the IP reachability information (IP address or FQDN)
of the outbound SIP Proxy Server [RFC3261]. Two means have been
defined in the past to provision such information:
1. DHCPv6 SIP options [RFC3319].
2. Dedicated 3GPP PCO to convey the address of the P-CSCF [CORE].
Nevertheless, these means are not sufficient because of the following
reasons:
1. PCO-IE is not mandatory in 3G networks (e.g., PCO information may
not be supported by terminals);
2. DHCPv6 is not required in all 3GPP releases. Moreover, the
support of DHCPv6 client is not mandatory in the IETF IPv6 node
requirements.
3. PCO-IE is not available in non-3GPP networks. This is very
critical when the UE performs a network attachment in a non-3GPP
network because the user won't have access to SIP-based services
if no alternative means are supported.
As a conclusion, auto-configuration [RFC4861] is required so that a
SIP UA can learn a set of SIP Proxy Servers.
1.2. Scope
Service providers need a reliable and flexible method to provision
the SIP Proxy Server address(es) to UEs (User Equipments). This
document defines a new ND option called SIP Proxy Server option that
contains the domain name of SIP Proxy Server(s). This option follows
the procedures defined in [RFC4861]. This works the same way that
the hosts learn routers and prefixes. The IPv6 host with SIP UA
implemented can learn a list of SIP Proxy Servers elements thanks to
this option. The SIP Proxy Server option can be sent along with
other options, such as DNS information [RFC6106], in the same RA
message simultaneously. The router sending the SIP Proxy Server in
RA must be configured with the Proxy Server information. The SIP
Proxy Server RA option can be used on any network that supports ND.
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2. SIP Proxy Server Option
The SIP Proxy Server Option contains a domain name representing the
SIP outbound Proxy Server. Figure 1 shows the SIP Proxy Server
Option format.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
: SIP Server Domain Name :
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Where
o Type is the RA SIP Proxy Server Option type
o Length is a 8-bit unsigned integer. The length of the option is
in unit of 8 octets.
o Reserved is for future use.
o Lifetime is a 16-bit unsigned integer. The lifetime associated
with the SIP Proxy Servers in units of seconds.
o SIP Server Domain Name: The domain names of the SIP outbound proxy
servers for the client to use. The domain names are encoded as
specified Section 3.1 of [RFC1035]. Underlying name resolution
libraries are used to resolve the name included in this option.
Upon receipt of an RA SIP Proxy Server option, the IPv6 host MUST
verify that the option length does not exceed 255 octets [RFC1035].
The IPv6 host MUST verify the FQDN is a properly encoded as detailed
in Section 3.1 of [RFC1035]. Once the FQDN conveyed in a SIP Proxy
Server RA option is validated, the included name is passed to the
name resolution library (see Section 6.1.1 of [RFC1123]) to retrieve
the corresponding IP address.
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3. IANA Considerations
This document requests IANA to assign a new option code for:
o SIP Proxy Server
4. Security Considerations
This document does not introduce any new security in addition to what
has been identified in [RFC4861] and [RFC3261].
5. References
5.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
5.2. Informative References
[CORE] 3GPP 24.008, "3GPP 24.008 -- Mobile radio interface Layer
3 specification; Core network protocols; Stage 3",
December 2008.
[RFC1123] Braden, R., "Requirements for Internet Hosts - Application
and Support", STD 3, RFC 1123, October 1989.
[RFC3319] Schulzrinne, H. and B. Volz, "Dynamic Host Configuration
Protocol (DHCPv6) Options for Session Initiation Protocol
(SIP) Servers", RFC 3319, July 2003.
[RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 6106, November 2010.
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Authors' Addresses
Mohamed Boucadair
France Telecom
Rennes, 35000
France
Email: mohamed.boucadair@orange-ftgroup.com
David Binet
France Telecom
Rennes
France
Email: david.binet@orange-ftgroup.com
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