Subject: [Fwd: [SIP] What does that 'maddr' mean?]

From: Alan Johnston <[email-masked]>
Date: Fri, 13 Apr 2001 22:51:40 -0500

Hi,

In this call flow, the BYE should also have a maddr in the Request-URI.

Maddr can either mean multicast address or, more commonly a second
address.  In this case, it is the latter.  This is because the request
is not being sent directly to the entity identified by the username and
host in the Request-URI, instead it is being sent to a Firewall proxy
(outbound proxy) which is identified by the address in the maddr.  Maddr
is also often used in Record-Route and Route headers for similar
reasons.

A simpler example URL would be of the form
sip:[email-masked];maddr=5.6.7.8  In this example, the request should be
sent to the secondary IP address 5.6.7.8 instead of the IP address in
the host portion 1.2.3.4.

Hope this helps.

Thanks,
Alan Johnston
WorldCom
sip:[email-masked]

-------- Original Message --------
Subject: [SIP] What does that 'maddr' mean?
   Date: Sat, 14 Apr 2001 11:28:54 +0900
   From: ÀÌÈñ¼® <[email-masked]>
     To: [email-masked]

This is draft-ietf-sip-call-flows-04.txt. 3.1.5 Successful SIP to SIP
through SIP Firewall Proxy    User A          FW Proxy         Proxy
1          User B
     |                |                |                |
     |   INVITE F1    |                |                |
     |--------------->|   INVITE F2    |                |
     |    (100) F3    |--------------->|   INVITE F4    |
     |<---------------|    (100) F5    |--------------->|
     |                |<---------------|    (100) F6    |
     |                |                |<---------------|
     |                |                |      180 F7    |
     |                |     180 F8     |<---------------|
     |     180 F9     |<---------------|                |
     |<---------------|                |      200 F10   |
     |                |    200 F11     |<---------------|
     |     200 F12    |<---------------|                |
     |<---------------|                |                |
     |     ACK F13    |                |                |
     |--------------->|     ACK F14    |                |
     |                |--------------->|     ACK F15    |
     |                |                |--------------->|
     |    RTP Media   |        Both Way RTP Media       |
     |<==============>|<===============================>|
     |     BYE F16    |                |                |
     |--------------->|     BYE F17    |                |
     |                |--------------->|     BYE F18    |
     |                |                |--------------->|
     |                |                |     200 F19    |
     |                |     200 F20    |<---------------|
     |     200 F21    |<---------------|                |
     |<---------------|                |                |
     |                |                |                |User A sends
INVITE , ACK , BYE message to FW Proxy.INVITE, ACK message have a maddr
parameter in their Request-URI,but BYE message doesn't have maddr
parameter.is this why? First of all,I don't understand why the maddr
parameter is needed in this flow.and i want to know that general meaning
of maddr parameter. Best Regard.Have a nice day!!!

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