SM: Session Manager not forwarding 503 messages to Cisco

Doc ID    SOLN206846
Version:    1.0
Status:    Published
Published date:    24 Jul 2012
Author:   
Guest User
 

Details

Session Manager is not forwarding 503 error from ESBC to Cisco Border Element.
Avaya Session Manager Software Version Inventory
Release: 6.1.5.0.615006
Call Processing: 6.1.5.0.615006-1
Management: 6.1.5.0.615006-1
SM Tools: 6.1.5.0.615006-1
DRS: 6.1.5.0.615006-1
CDR: 6.1.5.0.615006-1
NCS: 7.50.08-00
Security Module: 6.1.6.0.591-1
Firewall: 6.1.6.0.591-1
SIP A/S Management Server: 8.1.13.0
SIP A/S Service Director: 8.1.13.0
SIP A/S Service Host: 8.1.13.0
SAL Agent: 6.1-1.0.0.108.208
OS: Red Hat Enterprise Linux Server release 5.5 (Tikanga ) 5.5.0.2Orginiation Number: +16107322486, Destionation Number: +16038852400As soon as acceptance testing began.A balcklist was added to the ESBC

Problem Clarification

The Cisco Phone user makes a call to a blocked number. The call is routed to the ESBC, which returns a 503 because the number is on a blacklist. The Avaya Session Manager receives the 503, and continues to attempt to complete the call. The Avaya Session Manager never forwards the 503 to the Cisco Border Element. After 80 seconds the Cisco Call Manager times out, and routes the call out a PSTN trunk.

Cause

Problem is the double quotes (“) on the reason phrase of the response (503 "No Routes Found"). As per the RFC double quotes are not allowed as part of the response reason description. On the traces, the 503 gets to the Asset (SM100), and it is then forwarded to the SIPAS, but is not showing in the traceSM.log indicating the parsing error. On the corresponding sipas.log, you will see an error there.

Here extracts from the RFC about the grammar, notate double quotes (notated as DQUOTE) are not part of the allowed characters:

Reason-Phrase = *(reserved / unreserved / escaped
/ UTF8-NONASCII / UTF8-CONT / SP / HTAB)

alphanum = ALPHA / DIGIT
reserved = ";" / "/" / "?" / ":" / "@" / "&" / "=" / "+"
/ "$" / ","
unreserved = alphanum / mark
mark = "-" / "_" / "." / "!" / "~" / "*" / "'"
/ "(" / ")"
escaped = "%" HEXDIG HEXDIG
UTF8-NONASCII = %xC0-DF 1UTF8-CONT
/ %xE0-EF 2UTF8-CONT
/ %xF0-F7 3UTF8-CONT
/ %xF8-Fb 4UTF8-CONT
/ %xFC-FD 5UTF8-CONT
UTF8-CONT = %x80-BF

Solution

Have the SBC to remove the double quotes to fix this issue (503 No Route Found)


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