[Asterisk-Users] GR303

[Jerimiah Cole]

Rich Adamson wrote:
> I'm within a couple of weeks of attempting this by interfacing asterisk
> with a Siemens CO switch via gr303. All the physical components are in 
> place, just need to find some time to config asterisk, etc. This CO
> switch already has something like 30 remote concentrators (from another
> manufacturer) in solid production, therefore I have little concern with
> the Siemens gr303 implementation; the asterisk code is unknown at this
> time.

I'm in basically the same position with the 5E.  I have 4 or 5 existing 
303 interfaces in service.  I've tested the newly provisioned interface 
with other equipment with success.  Connecting to Asterisk has been 
fruitless so far.  I have a config that doesn't generate any errors in 
Asterisk, but the switch is unable to bring up the EOC.

> One of the Digium employees recently completed a test involving looping
> two T1's on asterisk (one interface config'ed as the network side and
> the other interface config'ed as a concentrator). He was able to complete
> calls via the loop which only suggests that base gr303 support for both
> is in place. The asterisk code to interface with a remote concentrator
> has been in place for over a year suggesting a rather solid understanding
> of the protocol requirements. However, No one knows for sure whether 
> asterisk's gr303 support is or is not complete enough to interface with 
> CO switches, but there is also no known concerns (or even tests) either.

Sounds like we're both in a position to find out.  I wonder if that 
Digium employee is listening and could nudge us in the right directon 
with some config examples? :)

> It is known the asterisk gr303 support does _not_ include any maintenance
> channel, therefore definitions within the CO switch (or concentrator) and
> definitions within asterisk have to be manually mapped and maintained.

That's good to know.

> Other day to day maintenance functions (eg, remote deactivation functions)
> are obviously not supported either. Not sure if that will be any sort of
> issue or not, or even how a CO switch reacts when it receives no response
> from asterisk.

AT&T/Lucent implementations are notoriously picky about following spec, 
so this may be an issue for me.  I haven't attacked this with a protocol 
analyzer yet.

> I'm not a programmer, but its my understanding (which could be wrong) that
> gr303 is a rather simple protocol (in relative terms). Its also my
> understanding that Mark is one of the primary developers of the code,
> therefore if there are compatibility issues uncovered, identifying and
> correcting those issues may be time consuming due to demands on his time.

I do beleive that a solid 303 implementation could make Asterisk more 
attractive, especially to ILECs.  This is more of a curiousity for me at 
this point, I'm happy using PRI.

Thanks for the info!  I'd like to hear how your experiment with the 
Siemens goes.

Jerimiah
Tularosa Communications