Subject: How does a Registrar inform UA about deregistration?

From: "Anoop Tripathi" <[email-masked]>
Date: Thu, 12 Aug 1999 11:25:27 -0500

Take an implementation where the Proxy/Registrar in implemented in one box.

A UA registers with Proxy/Registrar and expects the Proxy/Registrar to forward
all calls to it that are intended for this UA.

Now the proxy/Registrar  wants to go under maintenance. How does the Proxy
inform the UA that it should register with some other server.

 To summarize , H323 has RRQ , SIP has REGISTER. What is the equivalent of URQ
in SIP ?

Anoop

---

From: "Stephen Sprunk" <[email-masked]>
Date: Thu, 12 Aug 1999 12:02:22 -0500

UA registers with sip.example.com.  sip.example.com now wants to go down for
maintenance.  You propose that the UA needs to register with another server.
However, the point of registration is that [email-masked] will work..
Now we say that the new URL is [email-masked]?  That breaks the
whole purpose of registration.

I would envision a setup where you have a redundant cluster of machines all
answering for sip.example.com, either via a L4 switch or via multiple SRV
records.  When a registration comes in to one server, that server would be
responsible for notifying all other servers about it (since they're all
authoritative) or updating the central database they all use (like a
high-availability SQL server cluster), depending on the implementation.
Then if you needed to do maintenance on any server, you either remove it
from the L4 switch or from the SRV record list, and it simply stops
receiving queries/registrations.  When it comes back up, it is responsible
for resynchronizing with the rest of the server cluster.

S

Stephen Sprunk, K5SSS, CCIE#3723
Network Consulting Engineer
Cisco NSA   Dallas, Texas, USA
e-mail:[email-masked]
Pager: +1 800 365-4578
Empowering the Internet Generation

----- Original Message -----
From: Anoop Tripathi
To: [email-masked]
Sent: Thursday, August 12, 1999 11:25
Subject: How does a Registrar inform UA about deregistration?

A UA registers with Proxy/Registrar and expects the Proxy/Registrar to
forward
all calls to it that are intended for this UA.

 To summarize , H323 has RRQ , SIP has REGISTER. What is the equivalent of
URQ
in SIP ?

Anoop