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IM sticky loadbal


A new requirement with our client to run Instant Messaging (chat) servers behind CSS. Need to load balance between pool of "Microsoft Live Communications Server 2005 with SP1 Enterprise Edition".

Have anyone tried these servers behind a CSS?

What adv-bal sticky would you recommend. MS recommends a TCP-level affinity. I could not find anything other that src-ip-dest-port. Any help much appreciated.


Community Member

Re: IM sticky loadbal

I would use layer 4 sticky.

Using Layer 4 Sticky

Layer 4 sticky functions identically to Layer 3 sticky, except that it sticks based on a combination of source IP address, protocol, and destination port. Layer 4 sticky also uses a sticky table and has the same limitations as Layer 3 sticky.

If the CSS sees the same IP address with two different destination ports, it will use two entries. You can also apply sticky mask to Layer 4 sticky.

If you are concerned about whether your site can handle all of the simultaneous sessions, then consider using the Layer 5 advanced-balanced methods of arrowpoint-cookie, cookie, cookieurl, or url.

Read more about it at this link.

Please rate if you find it usefull.


Re: IM sticky loadbal


Thanks for the input. Really a valuable one.

Andreas, I do not think I am comfortable using a L5 based adv-stickiness as they are mainly provided for http header or url based ones, in other words they holds good for the browser-imitated traffic rather than an application-initiated traffic. In my situation I do not use browsers at all as you might aware it would be a pure chat application.

Question to Cisco.:-

How about making a provision for adding one more adv-bal method on the fleet of available methods, based on the ?source-ip-src-address? in future versions. The dest port remains the same and not much we can make use of it. However, the src port chosen by the client PC is random and stable until a RST-Ack/Fin-ACK. Having one on the CSS, would be provide more options to those who do the L4 sticky-balancing. This would be beneficial as well to those who struggle with the 'mega proxy' menace and the sticky-mask to rectify it, having used the adv-srcip-bal.

?????Gilles are you there?.?


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