Configuring SIP, SPCP, and NAT
Configuring SIP
Cisco Small Business SPA300 Series, SPA500 Series, and WIP310 IP Phone Administration Guide 125
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Reg Retry Long 
Random Delay 
Random delay added to Register Retry Long Intvl value 
when retrying REGISTER after a failure. 
Minimum and maximum random delay to be added to the 
long timer. Random delay range (in seconds) to add to the 
Register Retry Long Intvl when retrying REGISTER after a 
failure. Defaults to 0, which disables this feature. 
Not applicable to Cisco WIP310.
Reg Retry Intvl 
Cap
Reg_Retry_Intvl_Cap—Maximum value of the exponential 
delay. The maximum value to cap the exponential backoff 
retry delay (which starts at the Register Retry Intvl and 
doubles every retry). Defaults to 0, which disables the 
exponential backoff (that is, the error retry interval is always 
at the Register Retry Intvl). When this feature is enabled, the 
Reg Retry Random Delay is added to the exponential 
backoff delay value. The range is from 0 to 268435455.
Not applicable to Cisco WIP310.
Sub Min Expires Lower limit of the REGISTER (subscribe) expires value 
returned from the proxy server. The range is from 0 to 
268435455. Defaults to 10 seconds.
Sub Max Expires Upper limit of the REGISTER (subscribe) min-expires value 
returned from the proxy server in the Min-Expires header. 
The range is from 0 to 268435455. Defaults to 7200 
seconds.
Sub Retry Intvl The retry interval when the last Subscribe request fails. The 
range is from 0 to 268435455. Defaults to 10 seconds.
1. Cisco IP phones can use a RETRY-AFTER value when it is 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 to REGISTER again. If a RETRY-AFTER header is not present, the 
phone waits for the value specified in the Reg Retry Interval or the Reg Retry Long 
Interval.
Parameter Description