[SR-Users] [newbie] questions

[David]

Sounds like you would really benefit from hiring a consultant.


On 1/30/12 12:00 PM, Me wrote:
> Apologies if any of the questions below are a bit dumb - I don't 
> pretend to be an expert in SIP/VOIP - I am just an ordinary user 
> looking for answers.
>
> Our current setup involves processing a small number of internal sip 
> accounts (up to 10, no more than that) and one "public" one (with a 
> separate registrar) in the following way:
>
> On our server we have three interfaces: eth0, eth1 and tun0. eth0 is 
> our entry point to the public internet, eth1 faces our internal 
> network and tun0 is a private vpn, which connects all our smartphones 
> to the internal network (via Wifi, EDGE/2G/3G etc). This gives us the 
> mobility.
>
> Up until now, we have been routing voip calls via a commercial (closed 
> source), very limited, terribly outdated (Pentium code base!) and 
> rather buggy sip proxy. I had to employ a lot of hacks on our server 
> in order to route calls as this proxy can only listen on a single 
> interface. It was also a nightmare to maintain. Unsurprisingly, I 
> decided that enough is enough and I am now determined to replace it.
>
> We route calls in the following way: all machines (PCs are all Linux 
> based) & smartphones have their own sip/voip client installed on them 
> (also using bluetooth). Internal calls are routed via the proxy 
> between ourselves either on the internal net (eth1), or between the 
> vpn and eth1 (eth1<->tun0).
>
> External calls (going out, i.e. outbound) are routed externally to our 
> registrar, using a single separate voip account, via eth1<->eth0 or 
> tun0<->eth0.
>
> As I am now looking to replace our proxy, I looked at Kamailio, but 
> was soon completely overwhelmed by it (no offence intended, it was 
> just too much to take at first). I would appreciate if any of you 
> could give me a hand, or at least point me in the right direction, 
> with the following issues:
>
> I presume I could configure Kamailio to listen on more than one 
> interface and act as a proxy. How do I do that, so that it listens on 
> all 3 interfaces and proxies requests in the following way:
> - calls made to <userX>@ourdomain.net to be routed internally via eth1 
> (internal net) or tun0 (private vpn);
> - calls made to anybody else to be routed externally via eth0 (public) 
> using the separate "public" sip account with our external registrar;
> - calls made to the public sip account (from outside - the "public") 
> need to be routed to a "nominated" internall account (say 
> <user0>@ourdomain.net);
> - all other (internal) calls need to be routed depending on which 
> interface this account has been registered/logged in - either the 
> internal net (eth1) or the private vpn (tun0 - the smartphones).
>
> Obviously, calls need to be received (and routed properly) from all 3 
> interfaces.
>
> Is all of this possible with Kamailio?
>
> I want to avoid unnecessary complexities of the setup (as I already 
> mentioned above - I am just a user and by no means an expert in 
> sip/voip) and do not want to deploy something I do not need - I need 
> to keep the memory footprint to a bare minimum, possibly without 
> sacrificing performance.
>
> Once this is done, I would then move on to the next phase and use IM & 
> ENUM, but this is once the above works.
>
> I looked at other alternatives, but I got very confused there as well 
> - I couldn't figure out what exactly is the difference between, say, 
> OpenSER, Kamailio, OpenSIPS and SIP-Router even? What is the best 
> software to use in order to achieve the above setup?
>
> One last thing - I am a developer by trade and I am not afraid of 
> "tweaking" things when needed. I was successful in compiling Kamailio 
> from source (I use Fedora on all our machines) and I was pleased that 
> I could exclude from the RPM .spec file the modules I think I did not 
> need.
>
> I also made some modification of my own to make the database modules 
> (mysql, postgresql and unixodbc) configurable in the same way the rest 
> of the modules are. I could submit patches, if needed, so that these 
> are incorporated into future releases - how do I do that?
>
> I could not do the same with OpenSIPS, however (which I also tried - 
> out of curiosity!) - everything there seems to be lumped and compiled 
> together regardless of whether it is needed or not.
>
> Any help as to helping me with the above issues is greatly 
> appreciated, many thanks in advance for taking the time!
>
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