[Serusers] request for comments

[Jev]

Thanks for your feedback Klaus,

Klaus Darilion wrote:
> 1. How will you do the load balancing? Do the several ser servers have a 
> single IP address? As the clients are behind NAT, the NAT traversal 
> always has to be done by the proxy which acceptet the registration of 
> the client (only this IP address is allowed to traverse the NAT in case 
> of symmetric NATs).

The router in my diagram will have "Stciky IP" which will maintain the 
udp connection between a UA, and the first ser front end it hits.

> Furthermore you have to ensure that all messages of a transaction 
> traverse the same proxy.

In my test environment I was rewriting the URI on the front and back end 
box with a hard coded host name, but this will get more complicated when 
I add more than one front end boxes. One option that I have been mulling 
is to possibly use the textops modules to rewrite the URI to the origin 
address of the recieved SIP message, this should make all messsages that 
the backend replys to will go to the originating front end ser. Does 
this make sense? Failing the textops module, I think I can run sed (or 
similar) on the sip message. Keeping the message rewriting inside the 
ser instance seems preferable to me.

> Another point is that only the SIP proxy which acceptet the registration 
> knows about the current location of a UA, except you use the t_replicate 
> feature.

I understand now that I will need to have a location (persistent or not) 
on the front end servers. I imagine it should not be a problem to use 
t_replicate() across all my front end servers, but will this mean that 
all ser front end servers will attempt to send udp ping packets to 
natted clients?


Thanks!
-Jev