Configuring Traversal Server Ports - Cisco TelePresence Video Communication Server Administrator's Manual

Field Description
H.323 Determines whether or not H.323 calls using Assent mode for firewall traversal are
Assent allowed.
mode
H.460.18 Determines whether or not H.323 calls using H.460.18/19 mode for firewall traversal
mode are allowed.
H.460.19 Determines whether the VCS Expressway operates in demultiplexing mode for
demux calls from locally registered endpoints.
mode
On: allows use of the same two ports for all calls.
Off: each call uses a separate pair of ports for media.
H.323 Determines which protocol the VCS Expressway uses if an endpoint supports both
preference Assent and H.460.18.
UDP probe The frequency (in seconds) with which locally registered endpoints send a UDP
retry interval probe to the VCS Expressway.
UDP probe The number of times locally registered endpoints attempt to send a UDP probe to the
retry count VCS Expressway.
UDP probe The interval (in seconds) with which locally registered endpoints send a UDP probe
keep alive to the VCS Expressway after a call is established, in order to keep the firewall's NAT
interval bindings open.
TCP probe The frequency (in seconds) with which locally registered endpoints send a TCP
retry interval probe to the VCS Expressway.
TCP probe The number of times locally registered endpoints attempt to send a TCP probe to the
retry count VCS Expressway.
TCP probe The interval (in seconds) with which locally registered endpoints send a TCP probe
keep alive to the VCS Expressway after a call is established, in order to keep the firewall's NAT
interval bindings open.

Configuring traversal server ports

The VCS Expressway has specific listening ports used for firewall traversal. Rules must be set on
your firewall to allow connections to these ports. In most cases the default ports should be used.
However, you have the option to change these ports if necessary by going to the Ports page
configuration > Expressway >
The options are:
Field
Media demultiplexing RTP port
Media demultiplexing RTCP port
Cisco VCS Administrator Guide (X6.1)
Ports).
Description
Port used for demultiplexing RTP media.
Default is 2776.
Port used for demultiplexing RTCP media.
Default is 2777.
Firewall traversal
(VCS
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