Lucent Technologies 5ESS User Manual

appended as an isup-oli= parameter in the From header. The
TAS OPS may include a Carrier ID Code and Carrier Selection
Information for the origination, appended as
cic= and csel=
parameters on the username portion of the SIP Request URI and
the SIP To header.
2. Because the transport layer is UDP, the SIP layer at the TAS OPS
will retransmit the INVITE until it receives a response, so the
5ESS
®
switch TPS will send a 100 TRYING response
immediately after receiving the INVITE to indicate to the OPS
that it can cease retransmissions. The 5ESS
®
switch TPS will
retransmit the 100 TRYING in response to INVITE
retransmissions it receives.
3. When the 5ESS
®
switch PSTN Gateway has selected an ISUP
trunk over which the call is to be routed to the terminating PSTN
switch, it constructs an ISUP IAM message for the PSTN side of
the call. Since there was no embedded ISUP IAM in the INVITE
from the IP TAS, the PSTN Gateway TPS must map information
from the SIP headers in the INVITE into ISUP parameters in the
IAM, according to the provisioning rules for SIP-to-PSTN
mapping on RC/V 5.83. Some of the mappings, given the
provisioning described for this scenario, are:
• SIP Request URI to ISUP Called Party information,
• SIP P-Asserted-Identity and Privacy headers to ISUP Calling
Party information and presentation restrictions,
• SIP Max-Forwards header to ISUP Hop Counter parameter,
• SIP
cic= carrier code treated like a received ISUP TNS in
sunsequent switch translations,
• SIP
csel= parameter to ISUP Carrier Selection Information,
• SIP
isup-oli= parameter to ISUP Originating Line
Information , and
• First and last SIP Diversion headers to ISUP Redirecting
information parameters.
Message Flows
Call Flow
....................................................................................................................................................................................................................................
235-200-118
Issue 3.02B, March 2007
Lucent Technologies
3-23

Lucent Technologies 5ESS Specifications

General

Brand	Lucent Technologies
Model	5ESS
Category	Switch
Language	English