JUNHYUK SONG
INTERNET DRAFT SAMSUNG ELECTRONICS
April 2003
SIP server IPCP configuration option for PPP
draft-song-pppext-sip-support-01.txt
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Abstract
This document defines a new configuration option for the PPP IPCP
(PPP Internet Protocol Control Protocol), to return a list of the
IPv4 addresses of SIP proxy servers. This option provides one
mechanism that a system may use to locate a SIP proxy server.
This approach is applicable for a system that is using PPP for the
link layer protocol and IP address allocation.
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1. Introduction
The SIP (Session Initiation Protocol)[3] is a signaling protocol
used for the session invitation, modification and termination.
The UAC(User Agent Client) sends a request to the UAS(User Agent
Server). However, the request message (INVITE) is not directly sent
to the callee UAS, it rather go through proxy servers, and possibly
redirect servers. This draft is specifying one mechansim that a
system may use to locate a SIP procy server.
This draft is specifying a IPCP option that allows SIP clients to
locate a list of SIP proxy servers that is to be used for all SIP
requests. This approach is applicable to the system utilizing PPP
for the link layer protocol and IP address allocation
(ex. 3GPP2 Packet Data System)
Note : the format and behavior of these options are quoted from
RFC1877 [2] for the sake of consistent implementation of PPP.
2. Configuration Options
The Configuration Option format and basic options are defined by
IPCP configuration option [4].
This document concerns the following values:
[?] Primary SIP Server Address
[?+1] Secondary SIP Server Address
2.1. Primary SIP server Address Option
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the primary SIP server Address
to be used on the local end of the link.
By default, no primary SIP server address is provided.
A summary of the Primary SIP Address Configuration Option format is
shown below. The fields are transmitted from left to right.
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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 | Primary-SIP-Server Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Primary-SIP-Server Address(cont)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
? (Primary SIP Proxy server)
Length
6
Primary-SIP-Address
The four octet Primary-SIP-Server Address is the address of the
primary proxy SIP server to be used by the local peer.
If all four octets are set to zero, it indicates an explicit
request that the peer provide the address information in a
Config-Nak packet.
Default
No address is provided.
1.3. Secondary SIP Server Address
Description
This Configuration Option defines a method for negotiating with
the remote peer the address of the secondary SIP server Address
to be used on the local end of the link.
By default, no secondary SIP address is provided.
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A summary of the Secondary SIP Address Configuration Option format is
shown below. The fields are transmitted from left to right.
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 |Secondary-SIP-Server Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Secondary-SIP-Server Addr (cont)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
?+1 (Secondary SIP Proxy server)
Length
6
Secondary-SIP-Address
The four octet Secondary-SIP-Server Address is the address of the
secondary SIP server to be used by the local peer. If all four
octets are set to zero, it indicates an explicit request that the
peer provide the address information in a Config-Nak packet.
Default
No address is provided.
3. IANA Considerations
Requires IPCP option number assignment
4. Acknowledgements
A major portion of the text in this memo was quoted from RFC 1877.
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References
[1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", STD 51,
RFC 1661, Daydreamer, July 1994.
[2] Steve Cobb, "PPP Internet Protocol Control Protocol Extensions for
Name Server Addresses" RFC 1877, Microsoft,
[3] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP:
session initiation protocol," Request for Comments 2543, Internet
Engineering Task Force, Mar. 1999.
[4] McGregor, G., "PPP Internet Control Protocol", RFC 1332, Merit,
May 1992.
Addresses
Questions about this memo can be directed to the authors:
JUNHYUK SONG
SAMSUNG ELECTRONICS.
Packet Technology System Lab.
Mobile Development Team
Phone: +82-31-279-3639
Email: junhyuk@telecom.samsung.co.kr
santajunman@yahoo.com
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