[Asterisk-Users] When/whether to use SER?

[Philipp von Klitzing]

Hi!

> 1 PRI to Telco
> 1 PRI to old PBX
> Several SIP phones with the intention of having approx. 200.

> Currently the traveling users have to VPN in first which I am sure is adding extra overhead to the calls.
> I have yet to open my server to the Internet to be accessible to travelers without VPN first.
> I have done some testing with VOIP provider though my firewall to FWD and VOIPSTUNT.
> 
> Where might SER help?

Let's see what I can come up with:

* Advantages:

- SER supposedly has SRTP encryption support today through an add-on; 
Asterisk isn't there yet (TLS is missing); with SRTP you can get rid of 
the VPN tunnel. See:
http://www.voip-info.org/tiki-index.php?page=Asterisk+encryption
- with SER multiple registrations with the same (!) user credentials 
become possible
- You get the full power of a true SIP proxy permitting you to freely 
modify SIP messages as you see fit

* Disadvantages:

- SER documentation isn't ideal especially when it comes to Asterisk 
integration, and you'll need to dive more closely into the SIP protocol 
details
- SER encryption is not that easy to set up; naturally you'll also need 
SIP phones that can do SRTP (at this moment the SNOM 360 softphone is 
probably the only softphone that supports SRTP, however this is rather a 
test and promotion software for the real hardware phone than a permanent 
solution for your users)
- you'll probably need the VPN anyway for web, email, database 
connectivity - only if you decide to go for hardware phones instead you 
might gain by not requiring the VPN
- You'll need to get used to and manage two instead of one VoIP system, 
and that for a case where Asterisk alone would be totally sufficient by 
itself
- You'll need to find a way to handle the MWI issue, see:
http://www.voip-info.org/tiki-index.php?page=Asterisk+at+large

Cheers, Philipp