Cisco Cisco Expressway 维护手册
example, some calls may use Duo Video, or other calls might be audio only).
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system supports up to 6000 relays, spread evenly across 6 ports where each port is limited to handling
1000 relays. This limit is not strictly enforced, so we recommend adding an SRV record for each port to enable
round robin.
round robin.
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Clustered Expressways: 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).
requesting client with the details of an alternative server in the cluster (the TURN server currently with the
most available resources).
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The Expressway's TURN services are supported over single and dual network interfaces (via the Advanced
Networking option). For dual network interfaces, the TURN server listens on both interfaces but relays are
allocated only on the Expressway's externally facing LAN interface.
Networking option). For dual network interfaces, the TURN server listens on both interfaces but relays are
allocated only on the Expressway's externally facing LAN interface.
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Microsoft ICE (which is not standards-based) is not supported by the Expressway-E's TURN server; to enable
communications between the Expressway and Microsoft clients that are registered through a Microsoft Edge
Server you need to use the
communications between the Expressway and Microsoft clients that are registered through a Microsoft Edge
Server you need to use the
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The TURN server does not support bandwidth requests. Traversal zone bandwidth limits do not apply.
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The Expressway-E TURN server supports TURN media over TCP and UDP. Configuration of the supported
protocols is available only through the CLI command
protocols is available only through the CLI command
xConfiguration Traversal Server TURN ProtocolMode
.
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The Expressway-E TURN server supports UDP relays over TCP; it does not currently support TCP relays.
Configuring TURN Services
key (this controls the number of TURN relays that can be simultaneously allocated by the TURN server).
The TURN page (Configuration > Traversal > TURN) is used to configure the Expressway-E's TURN settings.
The configurable options are:
Field
Description
Usage tips
TURN
services
services
Determines whether the Expressway offers TURN
services to traversal clients.
services to traversal clients.
TURN
requests port
requests port
The listening port for TURN requests. The default is
3478.
3478.
On Large systems you can configure a range of TURN
request listening ports. The default range is 3478 – 3483.
request listening ports. The default range is 3478 – 3483.
To allow endpoints such as Jabber
Video to discover TURN services, you
need to set up DNS SRV records for _
turn._udp. and _turn._tcp (either for
the single port, or range of ports as
appropriate).
Video to discover TURN services, you
need to set up DNS SRV records for _
turn._udp. and _turn._tcp (either for
the single port, or range of ports as
appropriate).
If you need to change the Turn
requests port (or range, for Large
systems) while the Turn services are
already On:
requests port (or range, for Large
systems) while the Turn services are
already On:
1.
Change Turn services to
Offand Save
Offand Save
2.
Edit the port number/range
3.
Change Turn services to
Onand Save
Onand Save
This is because changes to the port
numbers do not come into effect until
the TURN services are restarted.
numbers do not come into effect until
the TURN services are restarted.
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Cisco Expressway Administrator Guide
Firewall Traversal