Cisco Cisco Expressway
...only one UDP candidate (two lines, one for RTP and one for RTCP) and they are for the host (private,
presumably non-routable by Expressway address)
presumably non-routable by Expressway address)
and the B2BUA responds, for example:
a=candidate:1 1 UDP 2136431 84.233.149.125 56056 typ host
a=candidate:1 2 UDP 2136430 84.233.149.125 56057 typ host
a=candidate:4 1 UDP 1677215 194.100.47.5 60000 typ relay raddr 84.233.149.125 rport 56056
a=candidate:4 2 UDP 1677214 194.100.47.5 60001 typ relay raddr 84.233.149.125 rport 56057
...Host and Relay candidates are both offered.
Neither device will be able to reach the other’s private (host) address, and if the Lync client tries to bind to the
Expressway-E TURN server it will get rejected because the request will come from the server reflexive
address rather than private address and Lync client has not told the B2BUA what that IP address is.
Expressway-E TURN server it will get rejected because the request will come from the server reflexive
address rather than private address and Lync client has not told the B2BUA what that IP address is.
Thus, Lync Server and the Microsoft Edge Server must be configured such that a Lync client offers at least
one public address with UDP media for this scenario to work.
one public address with UDP media for this scenario to work.
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.
Reflexive 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.
connectivity 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.
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.
One way media: Lync client to Expressway-registered
endpoint
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.
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.
Calls traveling through the Microsoft Edge server are supported when using the B2BUA with the Microsoft
Interoperability option key applied to the “Lync 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 “Lync 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 FEP rather than the load balancer. See
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 FEP rather than the load balancer. See
addresses.
Microsoft Lync and Cisco Expressway Deployment Guide (X8.1)
Page 50 of 63
Appendix 1: Troubleshooting