Cisco TelePresence Video Communication Server Administrator's Manual page 95

Setting Description
Automatically Determines what happens when the VCS receives a SIP
respond to search that originated as an H.323 search.
SIP searches
Off: a SIP OPTIONS or SIP INFO message is sent.
On: searches are responded to automatically, without being
forwarded.
This option should normally be left as the default Off.
However, some systems such as Microsoft Office
Communications Server (OCS) 2007 do not accept SIP
OPTIONS messages, so for these zones it must be set to
On. If you change this to On, you must also configure pattern
matches to ensure that only those searches that actually
match endpoints in this zone are responded to. If you do not,
the search will not continue to other lower-priority zones, and
the call will be forwarded to this zone even if it cannot support
it.
Empty Determines whether the VCS generates a SIP INVITE
INVITE message with no SDP to send via this zone. INVITES with
allowed no SDP mean that the destination device is asked to initiate
the codec selection, and are used when the call has been
interworked locally from H.323.
On: SIP INVITEs with no SDP are generated.
Off: SIP INVITEs are generated and a pre-configured SDP is
inserted before the INVITEs are sent.
In most cases this option should normally be left as the
default On. However, some systems such as Microsoft OCS
2007 do not accept invites with no SDP, so for these zones
this should be set to Off.
Note that the settings for the pre-configured SDP are
configurable via the CLI using the xConfiguration
Zones Zone [1..1000] DNS Interworking SIP
commands. They should only be changed on the advice of
Cisco customer support.
SIP poison On: SIP requests sent to systems located via this zone are
mode "poisoned" such that if they are received by this VCS again
they will be rejected.
Off: SIP requests sent out via this zone that are received by
this VCS again will not be rejected; they will be processed as
normal.
Cisco VCS Administrator Guide (X6.1)
Zones and neighbors
Default Applicable
to
Off Neighbor
zones
DNS
zones
On Neighbor
zones
DNS
zones
Off Neighbor
zones
Traversal
clients
Traversal
servers
DNS
zones
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