Cisco Cisco Expressway
20
SIP B2BUA and Microsoft Lync
Expressway
B2BUA
Lync Edge Server
Lync Front-End
Internet
Expressway
Internal Firewall
External Firewall
“Lync gateway”
Expressway-C
Expressway-C
Expressway-E
Public IP only
NAT not supported
3478 *, 24000 – 29999 inbound
UDP if the Expressway is used for
media only to NAT
Public NAT supported on Expressway
Expressway IP can be private
Only Internal IP needed
3478 * outbound UDP from
B2BUA to Expressway
(assumes response back allowed)
3478 outbound UDP required
Lync Client
Lync Client
* On Large Expressway VM server deployments you can configure a
range of TURN request listening ports (3478 to 3483) .
range of TURN request listening ports (3478 to 3483) .