Cisco Cisco TelePresence Video Communication Server Expressway 관리 매뉴얼
Firewall traversal
Cisco VCS Administrator Guide (X7.0)
Page 237 of 488
n
its publicly-accessible address on the NAT device
n
a relay address on the TURN server
The endpoints then decide, by performing connectivity checks through ICE, how they are going to
communicate. Depending upon how the NAT devices are configured, the endpoints may be able to
communicate between their public-facing addresses on the NAT devices or they may have to relay the
media via the TURN server. If both endpoints are behind the same NAT device they can send media
directly between themselves using their internal host addresses.
communicate. Depending upon how the NAT devices are configured, the endpoints may be able to
communicate between their public-facing addresses on the NAT devices or they may have to relay the
media via the TURN server. If both endpoints are behind the same NAT device they can send media
directly between themselves using their internal host addresses.
After the media route has been selected the TURN relay allocations are released if the chosen
connection paths do not involve routing via the TURN server. Note that the signaling always goes via the
VCS, regardless of the final media communication path chosen by the endpoints.
connection paths do not involve routing via the TURN server. Note that the signaling always goes via the
VCS, regardless of the final media communication path chosen by the endpoints.
Capabilities and limitations
n
The VCS supports up to 1800 relay allocations. This is typically enough to support 100 calls but does
depend on the network topology and the number of media stream components used for the call (for
example, some calls may use Duo Video, or other calls might be audio only).
depend on the network topology and the number of media stream components used for the call (for
example, some calls may use Duo Video, or other calls might be audio only).
n
Clustered VCSs: if the requested TURN server's relays are fully allocated the server will respond to
the requesting client with the details of an alternative server in the cluster (the TURN server currently
with the most available resources).
the requesting client with the details of an alternative server in the cluster (the TURN server currently
with the most available resources).
n
The VCS's TURN services are supported over single and dual network interfaces. For dual network
interfaces, relays are allocated on the VCS's externally facing LAN interface.
interfaces, relays are allocated on the VCS's externally facing LAN interface.
n
ICE calls can be made from non-registered devices, but the destination device does need to be
registered to the VCS's Local Zone.
registered to the VCS's Local Zone.
n
Microsoft ICE (which is not standards-based) is not supported by the VCS Expressway's TURN
server; to enable communications between the VCS and Microsoft OCS/Lync clients that are
registered through a Microsoft Edge Server you need to use the
server; to enable communications between the VCS and Microsoft OCS/Lync clients that are
registered through a Microsoft Edge Server you need to use the
.
n
The TURN server does not support bandwidth requests. (Note that traversal zone bandwidth limits do
not apply.)
not apply.)
Configuring TURN services
TURN relay services are only available on a VCS Expressway. To use
you also need
the TURN Relay option key (this controls the number of TURN relays that can be simultaneously
allocated by the VCS).
allocated by the VCS).
The
TURN
page (
VCS configuration > Expressway > TURN
) is used to configure the VCS
Expressway's TURN settings.
The configurable options are:
Field
Description
Usage tips
TURN
services
services
Determines whether the VCS
offers TURN services to
traversal clients.
offers TURN services to
traversal clients.