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A Mechanism for Session Initiation Protocol (SIP) Avalanche Restart Overload Control

Document Type Expired Internet-Draft (individual)
Expired & archived
Authors Charles Shen , Henning Schulzrinne , Arata Koike
Last updated 2010-05-23
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


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.


Charles Shen
Henning Schulzrinne
Arata Koike

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)