Cisco Cisco TelePresence Video Communication Server Expressway 관리 매뉴얼
The VCS Expressway uses non-demultiplexed media for call legs directly to/from SIP endpoints (that is endpoints
which do not support Assent or H.460.19), or if the traversal server zone is not configured to use H.460.19 in
demultiplexing mode.
which do not support Assent or H.460.19), or if the traversal server zone is not configured to use H.460.19 in
demultiplexing mode.
Media demultiplexing ports on the VCS Expressway are allocated from the general range of traversal media ports.
This applies to all RTP/RTCP media, regardless of whether it is H.323 or SIP. On new installations of X8.1 or later, the
default media traversal port range is 36000 to 59999, and is set on the VCS Control (Configuration > Local Zones
> Traversal Subzone). In Large VCS Expressway systems the first 12 ports in the range – 36000 to 36011 by default –
are always reserved for multiplexed traffic. The VCS Expressway 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 VCS Expressway (Configuration > Traversal > Ports). On upgrades to X8.2 or later, the VCS Control retains the
media traversal port range from the previous version (could be 50000 - 54999 or 36000 - 59999, depending on source
version). The VCS Expressway retains the previously configured demultiplexing pair (either 2776 & 2777 or 50000 &
50001 by default, depending on upgrade path) and the switch Use configured demultiplexing ports is set to Yes. If
you do not want to use a particular pair of ports, switch Use configured demultiplexing ports to No, then the VCS
Expressway will listen on the first pair of ports in the media traversal port range (36000 and 36001 by default). In this
case, we recommend that you close the previously configured ports after you configure the firewall for the new ports.
This applies to all RTP/RTCP media, regardless of whether it is H.323 or SIP. On new installations of X8.1 or later, the
default media traversal port range is 36000 to 59999, and is set on the VCS Control (Configuration > Local Zones
> Traversal Subzone). In Large VCS Expressway systems the first 12 ports in the range – 36000 to 36011 by default –
are always reserved for multiplexed traffic. The VCS Expressway 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 VCS Expressway (Configuration > Traversal > Ports). On upgrades to X8.2 or later, the VCS Control retains the
media traversal port range from the previous version (could be 50000 - 54999 or 36000 - 59999, depending on source
version). The VCS Expressway retains the previously configured demultiplexing pair (either 2776 & 2777 or 50000 &
50001 by default, depending on upgrade path) and the switch Use configured demultiplexing ports is set to Yes. If
you do not want to use a particular pair of ports, switch Use configured demultiplexing ports to No, then the VCS
Expressway will listen on the first pair of ports in the media traversal port range (36000 and 36001 by default). In this
case, we recommend that you close the previously configured ports after you configure the firewall for the new ports.
For example, in a SIP call from within an enterprise to an endpoint at home through a VCS Control/VCS Expressway
pair, the only demultiplexing that would occur would be on the VCS Expressway ports facing the VCS Control:
pair, the only demultiplexing that would occur would be on the VCS Expressway ports facing the VCS Control:
Enterprise
endpoint
endpoint
VCS Control
VCS Expressway
Home
endpoint
endpoint
Non-
demuxed
Non-
demuxed
demuxed
Demuxed
Non-
demuxed
demuxed
RTP ports
36002 36004
36000 36002
RTCP ports
36003 36005
36001 36003
However, an H.323 call from within an enterprise to an Assent capable H.323 endpoint at home through the same
VCS Control/VCS Expressway would perform demultiplexing on both sides of the VCS Expressway:
VCS Control/VCS Expressway would perform demultiplexing on both sides of the VCS Expressway:
Enterprise
endpoint
endpoint
VCS Control
VCS Expressway
Home
endpoint
endpoint
Non-
demuxed
Non-
demuxed
demuxed
Demuxed Demuxed
RTP ports
36002 36004
36000 36000
RTCP ports
36003 36005
36001 36001
If the VCS Expressway has Advanced Networking, it will still use the same port numbers as described above, but they
will be assigned to the internal and external IP addresses.
will be assigned to the internal and external IP addresses.
Firewall Traversal Configuration Overview
This section provides an overview to how the VCS can act as a traversal server or as a traversal client.
VCS as a Firewall Traversal Client
The VCS can act as a firewall traversal client on behalf of SIP and H.323 endpoints registered to it, and any systems
that are neighbored with it. To act as a firewall traversal client, the VCS must be configured with information about
the systems that will act as its firewall traversal server.
that are neighbored with it. To act as a firewall traversal client, the VCS must be configured with information about
the systems that will act as its firewall traversal server.
You do this by adding a traversal client zone on the VCS client (Configuration > Zones > Zones) and configuring it
with the details of the traversal server. See
with the details of the traversal server. See
for more information. You
can create more than one traversal client zone if you want to connect to multiple traversal servers.
Note that:
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Cisco TelePresence Video Communication Server Administrator Guide