Avaya G250 Maintenance Manual page 81

Table 26: H.248 Link Recovery feature/adjunct interactions (continued)
Feature or adjunct
H.323 stations
Description
An IP phone that is on a call tries to return to the
primary MGC if it loses its signalling link (when
TCP keepalive fails) to the MGC. If the MGC is
aware of the call it allows the IP phone to
register. Otherwise, it rejects the registration
until the IP phone is not on any call.
Two H.323 IP stations can be connected to each
other in two ways:
Shuffled call. In this case, the RTP
●
streams from one phone terminate on the
other phone. This type of call setup does
not require any media gateway VoIP
resources. Therefore, the new MGC does
not know about the call.
Unshuffled call. In this case, the RTP
●
streams from each phone terminal on a
Media Processor resource (media
gateway VoIP engine or PN Prowler). The
Media Processor redirects the RTP
streams to the destination phone. This
type of connection configuration is used if
transcoding is needed, or if one of the IP
phones is in one network and the other is
in another network.
In the latter case, the MGC is aware of the call,
since the call is using media gateway resources.
The following are possible scenarios:
The two-party IP phone call is
●
reconstructed before the IP phones try to
register. When the IP phone registers, the
phone informs the MGC about the call
(through the "call Present" flag in RRQ).
The MGC rejects the registration and
asks the IP phone to register when it ends
the call.
System resets
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Issue 1.1 June 2005 81