[Asterisk-Users] any ISDN/PRI signaling experts out there?

Damon Estep damon at suburbanbroadband.net
Fri Aug 19 06:01:00 MST 2005


I have officially engaged in a pissing contest with the local Telco over
PRI calling name delivery.

The telco publishes their calling name delivery over PRI feature as
being bellcore gr-1367-core compliant.

The gr-1367-core spec states that the calling name is to be included as
a facility IE in the setup message, or sent in a subsequent facility IE
message with an indicator in the setup message that the CNAM will
follow.

Extensive testing and ISDN/PRI protocol analysis shows that the facility
IE they are sending out with the CNAM in it comes only after we have
sent back PROGRESS and ALERTING in response to the SETUP. If we block
the PROGRESS and ALERTING and sit and WAIT for the FACILITY we never get
it, the call will time out, so we know they are actually waiting for the
call to progress before sending the facility IE CNAM.

As far as I can tell the GR-1367-CORE spec does not define a maximum
delay in sending the facility IE or whether it is acceptable to wait for
PROGRESS and ALERT before sending it.

The setup is; Telco PRI Lucent 5ESS <> Lucent MAX TNT <> Asterisk

The MAX TNT responds to the Facility IE with ISDN error 98, invalid
message for call state.

The SIP INVITE from the TNT to Asterisk contains no Caller Name
information.

It seems really odd to me that a Lucent TNT can not translate the caller
ID Name info delivered by a Lucent 5ESS switch.

On the same setup, if I connect another PRI device to it that emulates
switch side signaling and includes the CNAM as a Display IE in the
setup, the SIP invite is properly formatted and * receives the calling
party name.

Does anyone here have enough experience with ISDN PRI signaling to
comment with some level of authority on this?

Damon



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