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Cisco IOS NAT PAT and SIP with Dual Redundant ISP

Robert Ho

Ok, so I have an 1841 router.  Router is doing PAT for inside hosts and phones, and is  connected to two ISPs.

Solution desired is that one of the ISPs get used  as a "backup".  So SLA policies go in, and voilla.  It fails over and  starts using the backup isp, until that backup isp comes back up (via a  pingable address in their network).

The only trouble in paradise is  this:

Existing  PAT translations do not get cleared, and so devices that are talking  constantly (such as SIP devices) always have existing translations, and  thus do not appear to fail over until they somehow create a new xlate  (for example, rebooting a sip device) o rmanually clearing the translations.

Data works fine as they can retransmit and create a new translation.

Is there a way, in conjunction with  ip sla policies, to force a clearing of all ip nat trans * ?  Or,  failing that, something else I should be using to get that functionality  out of this failover scenario?

Thanks in advance for your help.

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