[SR-Users] Overload Control

[Yang Hong]

Dear all,  >Kaplan, Michael A wrote:
> Sure - I'm referring to mechanisms for the server to advertise to upstream neighbors to reduce request rates. This could include methods that appear > in RFC 6357 (e.g. rate-limits, window-based control, loss-rate enforcement). I suppose the try-again-after method would be of interest as well.
>IETF RFC 6357 "Design Considerations for Session Initiation Protocol (SIP) Overload Control"
Can be found in the following link.
http://tools.ietf.org/rfc/rfc6357.txt Please note that mechanisms for the server to advertise to upstream neighbors to reduce request rates must modify SIP header. This is called "Explicit Overload Control Feedback" in RFC6357. Unfortunately Changing the SIP header requires a time-consuming standardization process, because all the SIP servers from different service providers in different countries have to implement new SIP with new headers.     >Kaplan, Michael A wrote:
>Some of the other overload control mechanisms described in the RFC (e.g. window based control and loss based control) would also be of interest to me. Not sure if public implementations exist or if they are restricted to research implementations. Yes. "Explicit Overload Control Feedback" proposed by RFC6357 are restricted to research implementations. Public implementations require cooperation from all the service providers of SIP. However, implicit overload control does not require any modification of SIP header and time-consuming standardization process. Any SIP server can implement implicit overload control.   >Alex Balashov wrote:
>You can always construct such a reply yourself, and append headers to it.Yes. But appending headerers requires RFC standardization process and cooperation from all the service providers of SIP at different countries all over the world.