[c-nsp] 2821 voice configuration

[Bernhard Schmidt]

Brett Looney <brett at looney.id.au> wrote:
>> we want to use a Cisco 2821 as SIP-PSTN media gateway and PRI switch
>> for a slow migration from an old PBX to a VoIP PBX (Asterisk)
><snip>
>> CISCO2821-V/K9		2821 Voice Bundle,PVDM2-32,SP Serv,64F/256D
>> VWIC-2MFT-E1		2-Port RJ-48 Multiflex Trunk - E1
>> PVDM2-32		32-Channel Packet Voice/Fax DSP Module
>> can anyone see any reason why this might not work?
> Depending on how the calls are terminated you may need significantly more
> DSP resources than you have right now. You might need double or triple that
> depending on the number of calls. Also, be aware that you may not be able to
> independently clock the two E1 interfaces.

Thanks for the answer.

>95% of the calls should be G.711, so that leaves me with 64 channels.
So in theory I should be able to fully utilize both E1s with calls
originating from SIP, right? What about E1-to-E1 calls that are just
switched in the box? Do they take any DSP resources at all?

Regards,
Bernhard