AudioCodes Mediant 4000 SBC User Manual page 891

User's Manual
Parameter
SBC Session-Expires
configure voip > sbc settings > sbc-sess-exp-
time
[SBCSessionExpires]
Minimum Session-Expires
configure voip > sbc settings > min-session-
expires
[SBCMinSE]
configure voip > sbc settings > sbc-session-
refresh-policy
[SBCSessionRefreshingPolicy]
Version 7.2
60. Configuration Parameters Reference
Description
request. The Max-Forwards value indicates the
remaining number of times this request message is
allowed to be forwarded. This count is decremented
by each server that forwards the request.
The parameter affects the Max-Forwards header in
the received message as follows:

If the received header's original value is 0, the
message is not passed on and is rejected.

If the received header's original value is less than
the parameter's value, the header's value is
decremented before being sent on.

If the received header's original value is greater
than the parameter's value, the header's value is
replaced by the user-defined parameter's value.
The valid value range is 1-70. The default is 10.
Defines the SBC session refresh timer (in seconds) in
the Session-Expires header of outgoing INVITE
messages.
The valid value range is 90 (according to RFC 4028)
to 86400. The default is 180.
Defines the minimum amount of time (in seconds)
between session refresh requests in a dialog before
the session is considered timed out. This value is
conveyed in the SIP Min-SE header.
The valid range is 0 (default) to 1,000,000, where 0
means that the device does not limit Session-Expires.
Defines the SIP user agent responsible for
periodically sending refresh requests for established
sessions (active calls). The session refresh allows SIP
UAs or proxies to determine the status of the SIP
session. When a session expires, the session is
considered terminated by the UAs, regardless of
whether a SIP BYE was sent by one of the UAs.
The SIP Session-Expires header conveys the lifetime
of the session, which is sent in re-INVITE or UPDATE
requests (session refresh requests). The 'refresher='
parameter in the Session-Expires header (sent in the
initial INVITE or subsequent 2xx response) indicates
who sends the session refresh requests. If the
parameter contains the value 'uac', the device
performs the refreshes; if the parameter contains the
value 'uas', the remote proxy performs the refreshes.
An example of the Session-Expires header is shown
below:
Session-Expires: 4000;refresher=uac
Thus, the parameter is useful when a UA does not
support session refresh requests or does not support
the indication of who performs session refresh
requests. In such a scenario, the device can be
configured to perform the session refresh requests.

[0] Remote Refresher = (Default) The UA (proxy)
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