Cisco Cisco Expressway
Note that in the above scenario the B2BUA may not offer the Server Reflexive address if the Server Reflexive address
is seen to be the same as the host address.
is seen to be the same as the host address.
Call between endpoint and Lync fails with reason 'ice processing failed'
If the search history on Expressway shows calls failing with 'ice processing failed', this means that all ICE connectivity
checks between the B2BUA and the remote Lync device have failed.
checks between the B2BUA and the remote Lync device have failed.
Verify that the TURN server on Expressway-E has been enabled and that the TURN user credentials on Expressway-E
and B2BUA configuration match properly. This failure could also indicate a network connectivity issue for
STUN/TURN packets between B2BUA, Expressway-E/TURN server and the far end TURN server/Microsoft Edge.
and B2BUA configuration match properly. This failure could also indicate a network connectivity issue for
STUN/TURN packets between B2BUA, Expressway-E/TURN server and the far end TURN server/Microsoft Edge.
One Way Media: Lync Client to Expressway-registered Endpoint
When using Microsoft Edge Server
When Lync clients register to Lync through a Microsoft Edge Server, the local IP address and port that the Lync client
declares is usually private and un-routable (assuming that the Lync client is behind a firewall and not registered on a
public IP address). To identify alternate addresses to route media to, the Lync client uses SDP candidate lines.
declares is usually private and un-routable (assuming that the Lync client is behind a firewall and not registered on a
public IP address). To identify alternate addresses to route media to, the Lync client uses SDP candidate lines.
Calls traveling through the Microsoft Edge server are supported when using the B2BUA with the Microsoft
Interoperability option key applied to the Gateway Expressway, and where the video architecture includes a
Expressway-E with TURN enabled and the B2BUA is configured to use that TURN server.
Interoperability option key applied to the Gateway Expressway, and where the video architecture includes a
Expressway-E with TURN enabled and the B2BUA is configured to use that TURN server.
When using a Hardware Load Balancer in front of Lync
Expressway modifies the application part of INVITEs / OKs received from Lync clients to make them compatible with
traditional SIP SDP messaging. Expressway only does this when it knows that the call is coming from Lync. If there
are problems with one-way media (media only going from Lync client to the Expressway registered endpoint), check
the search history and ensure that the call is seen coming from a Lync trusted host. Otherwise, the call may be
coming from a FE Server rather than the load balancer. See
traditional SIP SDP messaging. Expressway only does this when it knows that the call is coming from Lync. If there
are problems with one-way media (media only going from Lync client to the Expressway registered endpoint), check
the search history and ensure that the call is seen coming from a Lync trusted host. Otherwise, the call may be
coming from a FE Server rather than the load balancer. See
and configure Lync trusted
hosts containing the FE Servers' IP addresses.
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:
1.
_sips._tcp.<domain>
2.
_sip._tcp.<domain>
3.
_sip._udp.<domain>
Lync clients use:
■
_sipinternaltls._tcp.<domain> - for internal TLS connections
■
_sipinternal._tcp. <domain> - for internal TCP connections (only if TCP is allowed)
■
_sip._tls. <domain> - for external TLS connections
If Lync clients are trying to register with Expressway-E, it could be because the wrong SRV record points to it.
You must make sure that the six DNS records above do not resolve to overlapping addresses.
Lync clients only support TLS connection to the Microsoft Edge Server, so use the _sip._tcp.<domain> DNS SRV for
the Expressway-E.
the Expressway-E.
Call to PSTN (or Other Devices Requiring Caller to be Authorized) Fails With "404
not found"
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.
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.
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Cisco Expressway with Microsoft Lync Deployment Guide
Appendix 1: Troubleshooting