Cisco 521SG - Unified IP Phone VoIP Administration Manual page 238

Cisco SPA IP Phone Field Reference
SIP Tab
NOTE
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide
Parameter
Reg Retry Long Random
Delay
Reg Retry Intvl Cap
Sub Min Expires
Sub Max Expires
Sub Retry Intvl
Cisco IP phones can use a RETRY-AFTER value when received from a SIP proxy
server that is too busy to process a request (503 Service Unavailable message). If
the response message includes a RETRY-AFTER header, the phone waits for the
specified length of time before retrying to REGISTER again. If a RETRY-AFTER
header is not present, the phone waits for the value specified in the
Interval or the Reg Retry Long Interval
Description
Random delay range (in seconds) to add to
<Register Retry Long Intvl> when retrying
REGISTER after a failure. This feature was added
in Release 5. 1 .
Defaults to blank, which disables this feature.
The maximum value to cap the exponential back-
off retry delay (which starts at <Register Retry
Intvl> and doubles on every REGISTER retry after
a failure). In other words, the retry interval is
always at <Register Retry Intvl> seconds after a
failure. If this feature is enabled, <Reg Retry
Random Delay> is added on top of the
exponential back-off adjusted delay value. This
feature was added in Release 5. 1 .
Defaults to blank, which disables the exponential
back-off feature.
This value sets the lower limit of the REGISTER
expires value returned from the Proxy server.
This value sets the upper limit of the REGISTER
min-expires value returned from the Proxy server
in the Min-Expires header. Defaults to 7200.
This value (in seconds) determines the retry
interval when the last Subscribe request fails.
Defaults to 10.
parameter.
A
Reg Retry
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