Cisco Cisco Expressway
Video endpoint reports that it does not support the Lync
client SDP
client SDP
If a video endpoint reports that it does not support the Lync client SDP, for example by responding “400
Unable to decode SDP” to a SIP INVITE message containing the Lync multi-part mime SDP sent to it:
Unable to decode SDP” to a SIP INVITE message containing the Lync multi-part mime SDP sent to it:
1. Check whether the Lync Server is sending calls to the Expressway incoming IP port, rather than the
B2BUA IP port that should be receiving the incoming SIP messages.
2. Reconfigure Lync Server to send calls to the B2BUA IP port.
TLS neighbor zone to Lync Server is active and messaging is
sent from Expressway to Lync Server, but Lync debug says
Lync fails to open a connection to Expressway
sent from Expressway to Lync Server, but Lync debug says
Lync fails to open a connection to Expressway
The local host name and domain name fields must be configured in the Expressway
System > DNS
page so
that Expressway can use its hostname (rather than IP address) in communications. Lync requires the use of
Expressway hostname so that it can open a TLS connection to the Expressway.
Expressway hostname so that it can open a TLS connection to the Expressway.
Lync client initiated call fails to connect
If a call fails to connect, check that the endpoint, IP Gateway, MCU or ISDN Gateway is NOT in Microsoft
mode; ensure that it is in Standard or Auto mode. (From a H.323/SIP trace, an indication that the device is in
Microsoft mode is the presence of a “proxy=replace” field in the contact header of the 200 OK from the
device.)
mode; ensure that it is in Standard or Auto mode. (From a H.323/SIP trace, an indication that the device is in
Microsoft mode is the presence of a “proxy=replace” field in the contact header of the 200 OK from the
device.)
Lync responds to INVITE with ‘488 Not acceptable here’
There can be two causes for this message:
From IP address
This is normally seen if the B2BUA forwards an INVITE from a standards-based video endpoint where the
‘From’ header in the SIP INVITE only contains the IP address of the endpoint, e.g. “From:
<sip:10.10.2.1>;tag=d29350afae33”. This is usually caused by a misconfigured SIP URI in the endpoint. In
future versions of B2BUA, the “From”-header will be manipulated if necessary to avoid this issue.
‘From’ header in the SIP INVITE only contains the IP address of the endpoint, e.g. “From:
<sip:10.10.2.1>;tag=d29350afae33”. This is usually caused by a misconfigured SIP URI in the endpoint. In
future versions of B2BUA, the “From”-header will be manipulated if necessary to avoid this issue.
Encryption mismatch
Look for the reason for the 488. If it mentions encryption levels do not match, ensure that you have configured
encryption appropriately, either:
encryption appropriately, either:
n
“Lync gateway” Expressway has the Microsoft Interoperability option key included, or
n
Lync is configured such that encryption is supported (or set as “DoNotSupportEncryption”) – note that if the
encryption support is changed on Lync then a short time must be left for the change to propagate through
Lync Server and then the Lync client must be signed off and then signed back in again to pick up the new
configuration.
encryption support is changed on Lync then a short time must be left for the change to propagate through
Lync Server and then the Lync client must be signed off and then signed back in again to pick up the new
configuration.
Microsoft Lync and Cisco Expressway Deployment Guide (X8.1)
Page 48 of 63
Appendix 1: Troubleshooting