Load Balancing with SIP T-Server

[victor]

Hi,

I know it sounds a bit strange, but is there some sort of way to load-balance SIP T-Servers? My first reaction was to look into NLB or WCS but even if I could balance the requests from GW, I have tough time trying to figure out how to get SIP phones to connect to the right T-Server, unless I connect each client to every SIP T-Server out there. Does Genesys have any guidelines that I have overlooked?

[René]

Hi Vic,

The only "Genesys solution" I know about is load-balancing using Network SIP Server. Using that component you're able to balance incoming traffic between multiple SIP Servers. But each SIP Server is considered to be separated site so such configuration is considered to by multi-site.

I don't think it's possible to load-balance SIP Servers in "classic" way due SIP protocol limitation. Theoretically you can omit protocol's limitation by registering single SIP phone with multiple SIP Servers but it would be "mess"...

R.

PS. It strange that I haven't received your post via RSS. I would say that something is wrong with forum's RSS implementation because it isn't first time I found new post on web while not getting info about it via RSS...

[victor]

Hi, Rene,

thank you for SIP Server reply. This is exactly what I thought, but I was still hoping for some sort of break, because this would be something that would give Genesys an upper hand over other SIP products. Despite all of advantages of HA, requirement for WCS makes it possible for other SIP products to accomplish almost the same thing as well. I wish there was a way to get Genesys HA/LB without third-party products. URS is an excellent example of things done right. 

[CTIgem]

I think you need something like "openSER".

[René]

Hi Vic,

I do agree with you that it will be big benefit for Genesys having something like that. But there is one thing in the middle Genesys can't (unfortunately? ) control and that is SIP protocol.

IMHO Comparing with URS isn't fair because Genesys controls both sides - server and client in that case but in SIP world client side is outside Genesys control...

R.

[victor]

Well,

first of all, I was amazed at how well Genesys SIP worked last year. The only problems I had encountered that upset me were:

- lack of SIP development framework for client
- cumbersome HA for T/S through WCS

I tackled the first problem by developing our own Genesys SIP phone, and we used WCS for the second; however, altogether, it felt like using VBS because I did not have C#. It just the rest of the functionality was done so well, that I just can't stop and ask for the same features here as well.

Genesys' reliance on NLB (network load balancer) to handle this is proving to be rather problematic. Obviously, this is not really a great solution, because:

1. you need to have separate hardware to LB and it adds extra costs
2. there is 4 to 10 second switchover time when using Windows Cluster Server (I could not figure out a way to do it faster than that)
3. existing calls can no longer be controlled after switch-over (at least using RTC 1.3)


here is what I think:

comparing T-Server SIP with URs is not fair, and expecting the same thing from T/S as from URS is probably over the top. But... I do think that through the use of INFO message, SIP T-Server would be able to regulate the flow of messages from gateway and SIP phones. OpenSER (http://www.openser.org/) seems to be able to do it, so since there is a way to do it using INFO message, it would be great if new version of Genesys SIP T/S would be able to do it as well.

It would also be an awesome way to distinguish Genesys SIP T/S from all the other solutions out there.

Here is my wish list:
- load balancing for GVP, SM, SIP T/S
- basic SIP phone similar to GAD to allow users to build upon that
- ability to have multiple GVPs on the same server
- support for virtualization

There is already support for load-balancing for GVP and you can do load-balancing (sort of) with SM
I think most of the things I am wishing for are probably already there and I just do not know about it, so please, please, please if someone has an idea on how to LB these products, tell me

Best regards,
Vic

[tigersdood]

Hey All -

I'm curious if anyone has since had any additional experience with this topic. Specifically I'm involved with a client who is looking at load balancing endpoint registrations/messaging across a few SIP servers. I realize on the trunk side how network TServer could be leveraged but I'm focused on the client side of this.

Someone mentioned Openser or OpenSIPS I guess now. Has anyone tried putting a SIP proxy server in front of their SIP Servers yet? Aside from the potential of it just flat out not working for whatever reason it seems that would be some issues around managing endpoint extensions/dn's.

Curious if anyone has gone down this path yet.

Thanks!