Cisco TelePresence Administrator's Manual page 143

Setting Description
Automatically Determines what happens when the VCS receives a SIP search that
respond to 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 INVITE Determines whether the VCS generates a SIP INVITE message with no
allowed SDP to send via this zone. INVITES with 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]
[Neighbor/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 "poisoned"
mode 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.
SIP Determines whether or not the VCS allows encrypted SIP calls on this
encryption zone.
mode
Auto: SIP calls are encrypted if a secure SIP transport (TLS) is used.
Microsoft: SIP calls are encrypted using MS-SRTP.
Off: SIP calls are never encrypted.
This option should normally be left as the default Auto. However, this must
be set to Microsoft for Microsoft Office Communications Server (OCS)
2007 zones.
Cisco VCS Administrator Guide (X7.2)
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
Auto Neighbor
zones
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