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New Member

120 DSP used when only 60 calls are made


I have a AS5300 which is used to terminate voip traffic. It has 3 E1 ISDN PRI connection to PSTN, and it *seems* it has 120 codecs available. But this router is unable to handle more than 60 calls simultaneously.

This is output from 'show call resource voice stats':

Resource Monitor - Dial-up Resource Statistics Information:

DSP Statistics:

Utilization: 100.00 percent

Total channels: 120

Inuse channels: 120

Disabled channels: 0

Pending channels: 0

Free channels: 0

DS0 Statistics:

Utilization: 0.00 percent

Total channels: 124

Addressable channels: 0

Inuse channels: 0

Disabled channels: 0

Free channels: 0

It shows that 120 DSPs are used, though there are only 60 calls. 'show version' shows '60 DSP(s), 120 Voice resource(s)'. I have another AS5300 with 4 E1 PRI and it handles up to 110 calls.

What's wrong?

P.S. IOS is 12.3(18), VCWare Version: 11.41, DSPWare Version: 4.1.41, Technology: C549.

Super Bronze

Re: 120 DSP used when only 60 calls are made


Sounds like your gateway is using g729 (compressed codec) - this uses much less bandwidth (8k payload instead of G711's 64K payload) at slightly lower quality...

Do a:

show dial-pee voice | i eer|codec

This should show what codec each peer is set to - the default is G729.

If you are running voice over high bandwidth or a LAN you may want to change this to save on DSPs...

You'll probably need to change the codec on your AS5300 and on the other end of the call leg...



Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
New Member

Re: 120 DSP used when only 60 calls are made

Yes, my gateway is using g729, but I doubt that this is the cause of my problem. I have another AS5300 with same VFC cards (as far as I can tell from seeing output of 'show version' and 'show vfc [12] board') which also uses g729 but it handles as much as 110 calls.

Any other hints?

New Member

Re: 120 DSP used when only 60 calls are made

It seems that one of two VFC cards was not working properly, though it seemed to be fully operational. After I have reloaded the router and downloaded latest vcware software into VFC cards, router reported 0 used dsp after reload and then number of used dsp and calls made matched always.

Problem solved.

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