Subject: [Sip] Comments on draft-ietf-sip-hop-limit-diagnostics-00

From: Fredrik Thulin <[email-masked]>
Date: Tue, 28 Feb 2006 11:05:47 +0100

Hi

I've read draft-ietf-sip-hop-limit-diagnostics-00 and have some 
comments. Generally I think the idea is very good.

First, a nit perhaps. The From: in the examples have a Display name of 
"Sip Send" without quotes. Aren't quotes required in this case 
according to RFC3261? Of course that part isn't very important to this 
particular draft, but examples might as well be wellformed in my 
opinion.

Secondly, and more important. If I'm not missing anything it might still 
be hard/impossible to unambigously identify the element that actually 
generated a 483.

If I get a 483 containing Via headers (in the message/sipfrag body) like 
the one on page 6 (section 2.3. Example) then I can guess/assume that 
the host that actually generated the 483 is the one running on 
192.0.2.162 port 5080, but I cannot know this for sure, can I? 

To clarify, perhaps "interop.pingtel.com" (as used in the example from 
the draft) has SRV records that make nine out of ten requests go to the 
first proxy in a cluster (P2A), but one in ten will go to the second 
proxy in the cluster (P2B).

The Via headers might then show what looks like a loop solely between P1 
and P2A, with no evidence to the sender that it was actually P2B that 
got the request when Max-Forwards reached zero and the 483 was 
generated (by P2B).

Perhaps this draft could suggest that the element generating 483's 
SHOULD include information about itself (hostname/IP and, if necessary, 
listening port) in some way?

/Fredrik

_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip