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ASA 5510 and SIP inspect

I was wondering if there is a limit with SIP inspect as it relates to number of established SIP calls.

So does SIP die after 50 calls, 100 calls etc.

I ask because the Juniper SSG and ISG firewalls have limits with thier Application Layer Gateways (ALG) which is similar to the SIP inspect in the ASA. Juniper does not post that the ALG has a limit so I found out the hard way. Then thier support told me this is not documented but each product has a different limit for the SIP ALG.

I just do not know if Cisco has a limit that is also not documented before there are issues with calls.

Any help or any pointers to documentation that speak to this would greatly be appreciated.



  • Firewalling

Re: ASA 5510 and SIP inspect

To the best of my knowledge it is just a limitation in traffic forwarding not raw number of simultaneous calls. All of the SIP traffic will have to be fixed up so you'll just need to keep an eye on the CPU and memory of the device as more calls are created.

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