1841 Packet loss

Mar 28, 2005 2 Replies
S

Here is the situation,


1841 with connected 100Mbs LAN and 100Mbs WAN (capped at 20Mbs). It's used to send VOIP calls. THe LAN side is connected to a VOIP GW sending via calls 16T1s, so 368 simulataneous calls.

When all 16 T1s are used we gets packet loss (between point to point's on the WAN link) and reports of garbled calls, if we only use 8 T1s all is well.



Here is a snapshot of the Traffic on the links..



30 second input rate 2003000 bits/sec, 2734 packets/sec 30 second output rate 3545000 bits/sec, 5000 packets/sec

So including both FE's that about 16000pps... lets 20kpps. According to the documentation an 1841 can handle 75000pps.



The CPU usage never gets above 10%, we have tried with and without cef and we have stress tested the link with about 18Mbs.



Any ideas?



Thanks


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A

Hello, Scott! You wrote on 28 Mar 2005 12:36:10 -0800:

S> Here is the situation,

S> 1841 with connected 100Mbs LAN and 100Mbs WAN (capped at 20Mbs). S> It's used to send VOIP calls. THe LAN side is connected to a VOIP S> GW sending via calls 16T1s, so 368 simulataneous calls.

S> When all 16 T1s are used we gets packet loss (between point to S> point's on the WAN link) and reports of garbled calls, if we only S> use 8 T1s all is well.

Which codec are you using? 16 T1 worth of G.711 is more than 20Mbps even without VoIP overhead.

With best regards, Andrey.

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S

G.729 with 60 bytes voice payload size, according to cisco that should be about 16.52 kbps per call.

So about 6Mbps total

Thanks, Scott

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