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Renew dhcp on sip request timeout – Cisco Linksys SPA9000 User Manual

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Linksys SPA9000 Administrator Guide

Document Version 3.01

Chapter 4 Configuring SPA9000 Features

Enhancements in Release 5.1

The first part of the REGISTER enhancement adds a randomized delay on top of the corresponding
nominal retry interval:

= range of randomized delay to add to before
retrying REGISTER (when is applied)

= range of randomized delay to add to before retrying REGISTER (when is applied)

The second enhancement is to allow exponential back off of the for each retry until
it reaches the maximum value defined in the parameter. If the value of the

parameter is less than the disabled.

Renew DHCP On SIP Request Timeout

The SPA9000 may sometimes have an invalid IP address even though the DHCP lease has not expired.
In these cases, the SPA9000 may not receive any packets until it renews the IP address lease with the
DHCP server. The Renew DHCP On SIP Request Timeout feature, introduced in Release 5.1, allows the
SPA9000 to discover that the currently assigned IP address is no longer valid. This feature triggers a
DHCP lease renewal whenever indicators suggest that the SPA9000 is not receiving packets.

The SPA9000 periodically sends SIP requests to register, make calls, and so forth. Each SIP request
normally receives a corresponding reply. If the SPA9000 fails to receive a reply to a SIP request this may
indicate an invalid local IP address.

With this enhancement, when the SPA9000 fails to receive a reply to a SIP request, a timer is started. If
no reply to any SIP request is received before the timer expires, the SPA9000 automatically performs a
DHCP lease renewal. If the renewal results in the same IP address, no further action is taken. If the
renewal results in a new IP address assignment, the SPA9000 reboots.