Codec and bandwidth requirements

Answered Question
Sep 25th, 2009

I'm in the process of choosing the right ISR for an implementation that's only going to be terminating PRIs (not routing data vlan traffic.) The different model ISRs have different interfaces, so I started to wonder exactly how many voice streams could be processed throug a given interface and a given codec. Can someone tell me if this looks correct?

1.54 Mbps (T1)


19.2 audio stream or 9.6 simulataneous audio conversations


64 audio streams or 32 simulataneous audio conversations

100 Mbps (FastEthernet)


1280 audio streams or 640 simultaneous audio conversations


4266.66 audio streams or 2133.33 simultaneous audio conversations

1000 Mbps (Gig Ethernet)


12800 audio streams or 6400 simultaneous audio conversations


42666.66 audio streams or 21333.33 or simultaneous audio conversations

I'm aware that there are greater constraints in the ISRs, such as their capacity to process the traffic and that there are limitation on the Packets Per Second they can process. However, if processing is not an issue does this math look reasonable?

I have this problem too.
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