[Serusers] request for comments

[Jev]

Andrei Pelinescu-Onciul wrote:
[snip]
> So all the packets comming from the same ip will be sent to the same
> fron end SER? (hashing after src ip)?

Yes, using ciscos "Sticky IP" which I admit, I do not know about, but 
I'm told it will do this job properly.

> Anyway there are some problems related to the nat traversal:
> 
> 1. nat ping - nat ping needs to access usrloc, so that it would know
> which users to ping. However on your setup the front-end servers have no
> ideea about this, so they wouldn't be able to nat ping. The "main"
> server (User accounts) knows who to ping but its ping won't traverse a
> symmetric nat (the nat will have an open binding only with the outbound
> proxy, which would be one of the load balanced front-ends).

I do realize this now, so I'm considering running a non-persistent 
usr_loc (no mysql back end) on all the front end servers, and using 
t_replicate between all of them. I admit I have not verified if this is 
possible, so please forgive me if I'm talking non-sense here at this 
stage. My concern here, as I mentioned in my reply to Klaus's post, is 
that if I use t_replicate will all my front end ser servers, will they 
all spit udp at a single natted client when the client has only one udp 
session with one front end server?


> 2. consider user A calling user B, where at least B is behind a nat.
> The invite would reach the "main" server which will look up B and will
> try to send the message to B's address. Unfortunately B's nat will drop
> the packet, because it has an open binding only between B and the load
> balanced ip. (this will work only if B has a full cone nat which is very
> very unlikely)

I'm not sure on the solution here. I will need to make the call go via 
the front end ser server that has the active udp session with the 
client. I'm going to sleep on this!


> 3. assuming the above stuff will work somehow, you still have to be very
> carefull to open only one rtp proxy session (since each front end has
> its own rtp proxy you should make sure you use force_rtp_proxy on only
> one of them, for the same call)


I agree, and I realize that I'm making some challenging issues for 
myself :)
Thank you Andrei for your comments!

-Jev