911/933 not completing with Skyetel Trunk

[Nash Williams]

I recently set up IncrediblePBX 13.0.192.19 with 3 GV trunks (via Obi200) and 2 Skyetel trunks. Skyetel supports E911, and they recommend testing with 933. In my testing with 933, the call does not complete. Any other "normal" calls complete as expected. I've reviewed my configuration a number of times, and have not been able to understand what the root issue is. I've attached some debugs, but a few warnings stand out to me:

SIP/2.0 401 Unauthorized
SIP/2.0 404 No destination
TRUNK Dial failed due to CHANUNAVAIL HANGUPCAUSE: 20 - failing through to other trunks
app_dial.c:2527 dial_exec_full: Unable to create channel of type 'SIP' (cause 20 - Subscriber absent)
app_macro.c:321 _macro_exec: No such context 'macro-outisbusy' for macro 'outisbusy'. Was called by 933@from-internal
SIP/2.0 503 Service Unavailable
channel.c:5080 ast_prod: Prodding channel 'SIP/300-000000ed' failed

E911 is enabled on both Skyetel trunks, with one dedicated to a specific extension.

I've opened a ticket with Skyetel as well, but was interested if anyone else had seen this type of issue before.

 

[deputyrover]

Nash, did you ever get this working?

 

[wardmundy]

@Nash Williams: Are you, by chance, using the SIP URI mod that was recently introduced??

If so, your log exposed a bug that treated 911 and 933 calls as internal calls when, in fact, they should have been processed by your outbound trunks. The fix is to simply reinstall the code which now has been updated.

cd /tmp
wget http://incrediblepbx.com/sipuri-mod.tar.gz
tar zxvf sipuri-mod.tar.gz
rm -f sipuri-mod.tar.gz
./install-sip-uri-mod.sh

 

[jibberish]

I've found Skyetel to be very picky on the INVITE headers, and inconsistent between their domestic call servers and their high cost servers.

I got 911/933 working the moment I got my phone server to make the INVITE "From" header " CNAM STRING <sip:[email protected]>;tag=;ladsjklsdkfjals" (where the 13230001111 is the Skyetel hosted DID that has E911 service enabled). This is confusing as normally my Caller ID is provided by the "P-Asserted-Identity" header without any problems from Skyetel.

I'm using FusionPBX, not Incredible PBX, but in my case, the username on the gateway had to be the Skyetel DID that has E911 service enabled... and that number was put into the "From" header, and Skyetel was then happy.

I hope this input helps everyone else out.

 

[Skyetel]

We are very picky with two products - 911/933 & High Cost. The reason for both is the same - traceback and identification.

We don't rely on P-Asserted-Identity for 911/933 or High Cost because PAI is can also be used for Privacy (Restricted CID) which can mess with tracebacks. Both products have high trace-back requirements, so we rely on strict FROM rules to make sure our Traceback tools (and the tools of our upstream/international gateways) will work as expected. PAI is also not supported on some legacy SIP Routers (which are common internationally) and rely on the FROM for CID.