AudioCodes Mediant 3000 User Manual page 943

User's Manual
Parameter
[SBCUserRegistrationTime]
CLI: config-voip>sbc general-
setting sbc-rand-expire
[SBCRandomizeExpires]
Web: SBC Proxy Registration
Time
[SBCProxyRegistrationTime]
Version 6.8
(the device responds with this value to the user). You can also
configure this functionality per specific calls, using IP Profiles
(IpProfile_SBCUserRegistrationTime). For a detailed description of
this parameter and for configuring this functionality in the IP Profile
table, see ''Configuring IP Profiles'' on page 329.
Note: If this functionality is configured for a specific IP Profile, the
settings of this global parameter is ignored for calls associated with
the IP Profile.
Defines a value (in seconds) that is used to calculate a new value
for the expiry time in the Expires header of SIP 200 OK responses
for user registration and subscription requests from users.
The expiry time value appears in the Expires header in REGISTER
and SUBSCRIBE SIP messages. When the device receives such a
request from a user, it forwards it to the proxy or registrar server.
Upon a successful registration or subscription, the server sends a
SIP 200 OK response. If the expiry time was unchanged by the
server, the device applies this feature and changes the expiry time
in the SIP 200 OK response before forwarding it to the user;
otherwise, the device does not change the expiry time.
This feature is useful in scenarios where multiple users may refresh
their registration or subscription simultaneously, thereby causing
the device to handle many such sessions at a given time. This may
result in an overload of the device (reaching maximum session
capacity), thereby preventing the establishment of new calls or
preventing the handling of some user registration or subscription
requests. When this feature is enabled, the device assigns a
random expiry time to each user registration or subscription and
thus, ensuring future user registration and subscription requests
are more distributed over time (i.e., do not all occur
simultaneously).
The device takes any random number between 0 and the value
configured by this parameter, and then subtracts this random
number from the original expiry time value. For example, assume
that the original expiry time is 120 and this parameter is set to 10. If
the device randomly chooses the number 5 (i.e., between 0 and
10), the resultant expiry time will be 115 (120 minus 5).
The valid value is 0 to 20. The default is 10. If set to 0, the device
does not change the expiry time.
Notes:

The lowest expiry time that the device sends in the 200 OK,
regardless of the resultant calculation, is 10 seconds. For
example, if the original expiry time is 12 seconds and this
parameter is set to 5, theoretically, the new expiry time can be
less than 10 (e.g., 12 – 4 = 8). However, the expiry time will be
set to 10.

The expiry time received from the user can be changed by the
device before forwarding it to the proxy. This is configured by
the SBCUserRegistrationTime parameter.
Defines the duration (in seconds) for which the user is registered in
the proxy database (after the device forwards the REGISTER
message). When set to 0, the device sends the Expires header's
value as received from the user to the proxy.
The valid range is 0 to 2,000,000 seconds. The default is 0.
943
51. Configuration Parameters Reference
Description
Mediant 3000