Cisco Cisco TelePresence Video Communication Server Expressway 관리 매뉴얼
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As the B2BUA must take the media, each call is classified as a traversal call and thus consumes a traversal
call license.
call license.
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) that can have a media
encryption policy applied.
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Configuring the B2BUA for Media Encryption
The B2BUA used for encryption (and ICE support) is a different instance to the B2BUA used for Microsoft Lync
integration. Whereas the Lync B2BUA has to be manually configured and enabled, the B2BUA used for encryption is
automatically enabled whenever an encryption policy is applied.
integration. Whereas the Lync B2BUA has to be manually configured and enabled, the B2BUA used for encryption is
automatically enabled whenever an encryption policy is applied.
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.
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.
(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 Applications > B2BUA > B2BUA
TURN servers).
B2BUA must be configured with the addresses of the TURN servers to offer (via Applications > B2BUA > B2BUA
TURN servers).
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:
handling a call between, for example, zone A and zone B:
ICE
support
setting
support
setting
Zone A
Off
On
Zone
B
Off
Standard VCS proxying behavior.
B2BUA is not normally invoked (however, see the
note below regarding media encryption policy).
note below regarding media encryption policy).
B2BUA is invoked.
B2BUA includes ICE candidates in messages to
hosts in Zone A.
hosts in Zone A.
On
B2BUA is invoked.
B2BUA includes ICE candidates in messages to
hosts in Zone B.
hosts in Zone B.
Standard VCS proxying behavior.
B2BUA is not normally invoked (however, see the
note below regarding media encryption policy).
note below regarding media encryption policy).
Effect of media encryption policy when combined with ICE support
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:
the ingress and egress zones or subzones:
ICE support
Media encryption
mode
mode
B2BUA
invoked
invoked
Effect on ICE negotiation
Both zones /
subzones = Off
subzones = Off
At least one zone /
subzone is not Auto
subzone is not Auto
Yes
The B2BUA will not perform any ICE negotiation with either
host.
host.
Both zones /
subzones = On
subzones = On
At least one zone /
subzone is not Auto
subzone is not Auto
Yes
The B2BUA will perform ICE negotiation with both hosts.
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Cisco TelePresence Video Communication Server Administrator Guide