Ip Dialing; Calls To Unknown Ip Addresses - Cisco TelePresence Administrator's Manual

IP dialing

Dialing by IP address is necessary when the destination endpoint is not registered with any system (such as
a VCS, Gatekeeper or Border Controller).
If the destination endpoint is registered with one of these systems, it may be possible to call it using its IP
address but the call may not succeed if the endpoint is on a private network or behind a firewall. For this
reason you are recommended to place calls to registered endpoints via other address formats, such as its
AOR or H.323 ID. Similarly, callers outside of your network should not try to contact endpoints within your
network via their IP addresses.

Calls to unknown IP addresses

Although the VCS supports dialing by IP address, it is sometimes undesirable for a VCS to be allowed to
place a call directly to an IP address that is not local. Instead, you may want a neighbor to place the call on
behalf of the VCS, or not allow such calls at all. The Calls to unknown IP addresses setting (on the
plan configuration page) configures how the VCS handles calls made to IP addresses which are not on its
local network, or registered with it or one of its neighbors.
The VCS considers an IP address to be "known" if it either:
is the IP address of a locally registered endpoint
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falls within the IP address range of one of the subzone membership rules configured on the VCS
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The VCS will always attempt to place calls to known IP addresses (providing there is a search rule for Any IP
Address against the Local Zone).
All other IP addresses are considered to be "unknown" and are handled by the VCS according to the Calls to
Unknown IP addresses setting:
Direct: the VCS attempts to place the call directly to the unknown IP address without querying any
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neighbors.
Indirect: the VCS forwards the search request to its neighbors in accordance with its normal search
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process, meaning any zones that are the target of search rules with an Any IP Address mode. If a match is
found and the neighbor's configuration allows it to connect a call to that IP address, the VCS will pass the
call to that neighbor for completion.
Off: the VCS will not attempt to place the call, either directly or to any of its neighbors.
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This setting applies to the call's destination address prior to any zone transforms, but after any pre-search
transforms, Call Policy or User Policy rules have been applied.
Note that in addition to controlling calls, this setting also determines the behavior of provisioning and
presence messages to SIP devices, as these messages are routed to IP addresses.
Calling unregistered endpoints
An unregistered endpoint is any device that is not registered with an H.323 gatekeeper or SIP registrar.
Although most calls are made between endpoints that are registered with such systems, it is sometimes
necessary to place a call to an unregistered endpoint.
There are two ways to call to an unregistered endpoint:
Cisco VCS Administrator Guide (X7.1)
Dial plan and call processing
Dial
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