Configuration manual

Name Range or Default Description
the session, for example
when the target of an
incoming call or a transfer
does not support the codec
originally negotiated on the
trunk.
Use Offerer's Preferred
Codec
Default = Off Normally for SIP calls, the
codec preference of the
answering end is used. This
option can be used to
override that behavior and
use the codec preferences
offered by the caller.
Codec Lockdown Default = Off Supports RFC 3264 Section
10.2 when Re-Invite
Supported and Codec
Lockdown are enabled. In
response to a SIP offer with a
list of codecs supported,
some SIP user agents supply
a SDP answer that also lists
multiple codecs. This means
that the user agent may
switch to any of those codecs
during the session without
further negotiation. The
system does not support
multiple concurrent codecs
for a session, so loss of
speech path will occur if the
codec is changed during the
session. If codec lockdown is
enabled, when the system
receives an SDP answer with
more than one codec from
the list of offered codecs, it
sends an extra re-INVITE
using just a single codec from
the list and resubmits a new
SDP offer with just the single
chosen codec.
Administering a Session Manager line for each branch
Implementing B5800 Branch Gateway for a CS 1000 Configuration October 2012 151