Configuring Ice Messaging Support - Cisco TelePresence Administrator's Manual

Zones and neighbors

Configuring ICE messaging support

The ICE support option is a per-zone and per-subzone configuration setting that controls how the VCS
supports ICE messages to and from SIP devices within that zone or subzone.
The behavior depends upon the configuration of the ICE support setting on the incoming (ingress) and
outgoing (egress) zone or subzone. When there is a mismatch of settings i.e. On on one side and Off on the
other side, the VCS invokes its back-to-back user agent (B2BUA) to perform ICE negotiation with the
relevant host.
All zones and subzones have ICE support set to Off by default.
When the B2BUA performs ICE negotiation with a host, it can offer TURN relay candidate addresses. To do
this, the B2BUA must be configured with the addresses of the TURN servers to offer (via
B2BUA > B2BUA TURN
The following matrix shows the VCS behavior for the different possible combinations of the ICE support
setting when handling a call between, for example, zone A and zone B:
ICE
support
Off
setting
Off Standard VCS proxying behavior.
B2BUA is not normally invoked (however, see the
note below regarding media encryption policy).
Zone
B
On B2BUA is invoked.
B2BUA includes ICE candidates in messages to
hosts in Zone B.
Effect of media encryption policy when combined with ICE support
The VCS also invokes the B2BUA if it has to apply a
than Auto). This table shows the effect on ICE negotiation behavior depending on the ICE support and media
encryption modes of the ingress and egress zones or subzones:
ICE support Media encryption
mode
Both zones / At least one zone /
subzones = Off subzone is not Auto
Both zones / At least one zone /
subzones = On subzone is not Auto
Both zones / Both zones / subzones
subzones = On = Auto
Note that:
B2BUA routed calls are identified in the call history by a component type of Encryption B2BUA.
n
A traversal call license is consumed when a call goes via the encryption B2BUA.
n
There is a limit of 100 concurrent calls (500 calls on Large VM servers) that can be routed via the encryption
n
B2BUA.
Cisco VCS Administrator Guide (X8.1.1)
servers).
Zone A
B2BUA
invoked
Yes
Yes
No
On
B2BUA is invoked.
B2BUA includes ICE candidates in messages to
hosts in Zone A.
Standard VCS proxying behavior.
B2BUA is not normally invoked (however, see the
note below regarding media encryption policy).
media encryption policy (any encryption setting other
Effect on ICE negotiation
The B2BUA will not perform any ICE negotiation with
either host.
The B2BUA will perform ICE negotiation with both hosts.
The VCS will not offer any TURN relay candidate
addresses to either of the ICE capable hosts. However,
note that each host device may have already been
provisioned with TURN relay candidate addresses.
Configuring ICE messaging support
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