AudioCodes Mediant 1000B User Manual page 1111

User's Manual
Parameter
SBC Proxy Registration
Time
sbc-prxy-rgstr-time
[SBCProxyRegistrationTi
me]
config-voip>sbc
general-setting
sbc-rand-expire
[SBCRandomizeExpires]
SBC Survivability
Registration Time
sbc-surv-rgstr-time
[SBCSurvivabilityRegistrat
ionTime]
[SBCEnableSurvivabilityN
otice]
Version 7.0
Defines the duration (in seconds) for which the user is registered in the
proxy database (after the device forwards the REGISTER message).
This value is sent in the Expires header. 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.
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 the parameter, and then subtracts this random number
from the original expiry time value. For example, assume that the
original expiry time is 120 and the 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 the 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 of the periodic registrations between the user and
the device, when the device is in survivability state (i.e., when
REGISTER requests cannot be forwarded to the proxy and are
terminated by the device). When set to 0, the device uses the value set
by the SBCUserRegistrationTime parameter for the device's response.
The valid range is 0 to 2,000,000 seconds. The default is 0.
Enables the device to notify Aastra IP phones that the device is
currently operating in Survivability mode. When this occurs, the Aastra
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59. Configuration Parameters Reference
Description
Mediant 1000B Gateway and E- SBC