Subject: I-D Action:draft-shen-sipping-avalanche-restart-overload-01.txt

From: [email-masked]
Date: Sun, 23 May 2010 15:00:02 -0700 (PDT)

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title           : A Mechanism for Session Initiation Protocol (SIP) Avalanche Restart Overload Control
	Author(s)       : C. Shen, et al.
	Filename        : draft-shen-sipping-avalanche-restart-overload-01.txt
	Pages           : 10
	Date            : 2010-05-23

When a large number of clients register with a SIP registrar server
at approximately the same time, the server may become overloaded.
Near-simultaneous floods of SIP SUBSCRIBE and PUBLISH requests may
have similar effects.  Such request avalanches can occur, for
example, after a power failure and recovery in a metropolitan area.
This document describes how to avoid such overload situations.  Under
this mechanism, a server estimates an avalanche restart backoff
interval during its normal operation and conveys this interval to its
clients through a new Restart-Timer header in normal response
messages.  Once an avalanche restart actually occurs, the clients
perform backoff based on the previously received Restart-Timer header
value before sending out the first request attempt.  Thus, the
mechanism spreads all the initial client requests and prevents them
from overloading the server.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-shen-sipping-avalanche-restart-overload-01.txt

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