Jitter Question

What is an acceptable Jitter Rate for an SLA with a service provider? MY provider is saying that they will guarantee that jitter will not go above 10 milliseconds and it will be measured in 5 minute intervals.

This is an MPLS network and we will run IP voice over this network. What amount of Jitter can cause voice communication problems? Is it 8 milliseconds?

Thank You for any responses, all responses are greatly appreciated. Have a wonderful day.

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Not sure about the exact answer but found this about some carriers

Qwest SLA 2ms maximum jitter - Measured Actual for Oct 2004: 0.10ms Viterla SLA 1ms maximum jitter Axiowave SLA 0.5ms maximum jitter Verio SLA 0.5ms average, not to exceed 10ms maximum jitter more than

0.1% of time Internap SLA 0.5ms maximum jitter



Reply to
Chad Mahoney

it depends on the codec setting, and the buffer settings (and the capabilities of the VoIP reciever).

you need a deep enough de-jitter buffer to cope with the jitter you have.

Since the buffer directly adds to the overall path delay, you want that to be low for lowest delay, but more jitter pushes up the number.

there is some inherent jitter in an IP system that the phones have to cope with - for example a router sending you packets down a x Mbps line sends a

1500 byte packet 1st, so your voice packet has to wait.

at 2 Mbps, 1500 bytes, is 12k bits, so roughly equivalent to 6 mSec, and slower lines get proportionally worse. And many networks have multiple slow hops, each of which can add to the jitter.

The overall target VoIP delay budget is something around 150 mSec 1 way - but that includes distance, store and forward, codec delay etc.

So - if your IP phone cannot cope with a few 10 of mSec of jitter, then it is going to have problems on a WAN.

a cisco bit:

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