DSP sharing

[samir.saad]

Hi,

I have a 3845 router voice bundle with 2 x NM-HDV2-2T1/E1. The load on the lines is 50%; i.e. maximum 60 channels will be carrying calls simultaneously. However, the router does not allow me to enable all four E1 interfaces. Is there a way to operate the 4 E1 lines with the on-board PVDM2-64?

Thanks

[Nicholas Matthews · Accepted solution]

Hi Samir,

For analog circuits, you cannot 'share' DSPs. These are allocated for each circuit on bootup.

Use 'show voice dsp group all', 'show voice dsp detail', and 'show voice port summary' to get a better idea of what is allocated.

This calculator helps:

http://www.cisco.com/cgi-bin/Support/DSP/cisco_prodsel.pl

[samir.saad]

Hi Nic,

Sorry if it is a dumb question, but aren't E1 circuits digital, not analog?

[Nicholas Matthews]

They're analog in the sense that we can't send IP packets over them. So technically yes, they're digital. We still do the same things on the DSP as if they were analog, however.