Cisco Cisco Expressway
Ensure that Lync environment has been configured to trust the Expressway which is sending these
messages, as described previously in this document.
messages, as described previously in this document.
Note, this can also be seen if a load balancer is used in front of the Lync, and Lync is configured to authorize
the Expressway (Lync sees calls coming from the hardware load balancer rather than from the Expressway).
the Expressway (Lync sees calls coming from the hardware load balancer rather than from the Expressway).
Lync client stays in ‘Connecting …’ state
Lync client does not change into the connected state until it receives RTP (media) from the device with which
it is in a call.
it is in a call.
Call to PSTN or other devices requiring caller to be
authorized fails with 404 not found
authorized fails with 404 not found
In some Lync configurations, especially where Lync PSTN gateways are used, calls are only allowed if the
calling party is authorized. Thus, the calling party’s domain must be the Lync Server domain. This means that
the endpoints must register to the video network with a domain that is the same as the Lync domain.
calling party is authorized. Thus, the calling party’s domain must be the Lync Server domain. This means that
the endpoints must register to the video network with a domain that is the same as the Lync domain.
Lync clients try to register with Expressway-E
SIP video endpoints usually use DNS SRV records in the following order to route calls to Expressway:
n
_sips._tcp.<domain>
n
_sip._tcp.<domain> and
n
_sip._udp.<domain>
Lync clients use:
n
_sipinternaltls._tcp.<domain> - for internal TLS connections
n
_sipinternal._tcp. <domain> - for internal TCP connections (only if TCP is allowed)
n
_sip._tls. <domain> - for external TLS connections
Lync clients only support TLS connection to the Edge Server. The _sip._tcp.<domain> DNS SRV record
should be used for the Expressway-E.
should be used for the Expressway-E.
B2BUA problems
B2BUA Lync Server status reports "Unknown" or "Unknown failure"
Check that the Expressway application has been added to the Lync trusted application pool and is configured
to contact the Expressway B2BUA via port 65072 . See
to contact the Expressway B2BUA via port 65072 . See
for more
information.
Lync problems
Run the Lync Server ‘Best Practices Analyzer’ to help identify configurations that may be incorrect on Lync
Server.
Server.
Microsoft Lync and Cisco Expressway Deployment Guide (X8.5)
Page 58 of 71
Appendix 2: Troubleshooting