Cisco Cisco Expressway 维护手册
The following diagram shows the media flows and typical port usage on the Expressway-E and Expressway-C. The
TURN server on the Expressway-E relays the media between the Jabber Guest client and the B2BUA on the
Expressway-C, and the media also flows between the B2BUA and the internal endpoint.
TURN server on the Expressway-E relays the media between the Jabber Guest client and the B2BUA on the
Expressway-C, and the media also flows between the B2BUA and the internal endpoint.
Outbound from Expressway-C (private) to Expressway-E (external/NAT address)
Purpose
Protocol
Expressway-C (source)
Expressway-E (listening
external/NAT address)
external/NAT address)
Media
UDP
36002 to 59999 **
24000 to 29999
Outbound from Expressway-C (private) to Expressway-E (DMZ internally-facing address)
Purpose
Protocol
Expressway-C (source)
Expressway-E (DMZ
internal listening)
internal listening)
SSH (HTTP/S tunnels)
TCP
Ephemeral port
2222
* On Large systems you can configure a range of TURN request listening ports. The default range is 3478 – 3483.
** The default media traversal port range is 36000 to 59999, and is set on the Expressway-C at Configuration
> Traversal Subzone. In Large Expressway systems the first 12 ports in the range – 36000 to 36011 by default – are
always reserved for multiplexed traffic. The Expressway-E listens on these ports. You cannot configure a distinct
range of demultiplex listening ports on Large systems: they always use the first 6 pairs in the media port range. On
Small/Medium systems you can explicitly specify which 2 ports listen for multiplexed RTP/RTCP traffic, on the
Expressway-E (Configuration > Traversal > Ports). If you choose not to configure a particular pair of ports (Use
configured demultiplexing ports = No), then the Expressway-E will listen on the first pair of ports in the media
traversal port range (36000 and 36001 by default).
> Traversal Subzone. In Large Expressway systems the first 12 ports in the range – 36000 to 36011 by default – are
always reserved for multiplexed traffic. The Expressway-E listens on these ports. You cannot configure a distinct
range of demultiplex listening ports on Large systems: they always use the first 6 pairs in the media port range. On
Small/Medium systems you can explicitly specify which 2 ports listen for multiplexed RTP/RTCP traffic, on the
Expressway-E (Configuration > Traversal > Ports). If you choose not to configure a particular pair of ports (Use
configured demultiplexing ports = No), then the Expressway-E will listen on the first pair of ports in the media
traversal port range (36000 and 36001 by default).
Troubleshooting Jabber Guest Services on Expressway
Packet loss on calls
Check if the Maximum Transmission Unit (MTU) on Expressway-E is too high. We recommended that you lower the
MTU size on the relevant network interfaces from 1500 to 1400 bytes.
MTU size on the relevant network interfaces from 1500 to 1400 bytes.
Jabber Guest client fails to connect and gets "Not Found on Accelerator" message
This error can occur if:
■
The Expressway-E domain is different from the Jabber Guest domain.
■
The SIP trunk between the Jabber Guest server and the Expressway-C is not active.
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Cisco Expressway Administrator Guide