Cisco Cisco Expressway
Purpose
Protocol
Edge server
Lync client
SIP/MTLS used between Lync Client and
Edge server for signaling (including any
ICE messaging to the Edge Server)
Edge server for signaling (including any
ICE messaging to the Edge Server)
TCP
5061
5061
SIP/TLS
TCP
443
443
STUN
UDP
3478
3478
UDP Media
UDP
50000-59999
1024-65535
TCP Media
TCP
50000-59999
1024-65535
Table 16 External Lync Client and Edge Server
Purpose
Protocol
Lync client / Edge
server
server
Expressway-E
ICE messaging (STUN/TURN)
(Expressway-E must listen on TCP 3478
for desktop sharing relay requests from
Lync clients, and on UDP 3478 for
A/V media relay requests)
for desktop sharing relay requests from
Lync clients, and on UDP 3478 for
A/V media relay requests)
UDP & TCP
3478
3478
UDP media
UDP
1024-65535
24000-29999
Table 17 External Lync Client / Edge Server and Expressway-E
Purpose
Protocol
B2BUA IP port
Transcoder
B2BUA communications with transcoder
(Cisco AM GW)
(Cisco AM GW)
TLS
65080
5061
Table 18 Between B2BUA and External Transcoder
How Many Media Ports are Required on the Gateway Expressway?
The UDP port range of the B2BUA on the Gateway Expressway is set to 1000 ports by default, starting at 56000 and
ending at 57000. That is the default destination range for media from Lync clients, and may be different in your Lync
environment.
ending at 57000. That is the default destination range for media from Lync clients, and may be different in your Lync
environment.
The B2BUA uses the UDP ports as follows:
Purpose
Call type
Number of ports used
Traversal of audio and video streams
Internal/external Lync client to SIP endpoint
8
RDP transcoding
Desktop share from Lync client
10
Maximum per call
Lync client sharing desktop
18
Connections from B2BUA to TURN server
Per TURN server connection
2
48
Cisco Expressway with Microsoft Lync Deployment Guide