Be frame relay clarification required

Unanswered Question
Jul 9th, 2007


Can somebody clarify about Be(exssive burst)

To use Be , we should have data to trasmit less than

Option 1: the contract cir i.e. it should be less than cir for ?whole second? as cir is given generally in second (we will be using Be in 2nd second if the have given data less than 1st second,but cann?t use in 1st sec itself )


Option2: should be taken for ?Tc ?(which is in mill second) i.e. if we give data less than Bc for a 1st Tc we could use it in 2nd Tc with in the ?same second?

Which option is the correct one?

Thanks is advance


vinay verma

I have this problem too.
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Edison Ortiz Tue, 07/10/2007 - 19:06

Be is traffic above the maximum speed (CIR). When you contract for a frame-relay circuit, you get Port Speed, CIR and MinCIR information. The Port Speed is usually higher than the CIR (specially if you are running multiple PVCs on that circuit) and you are often allowed to send packets at "Port Speed" and that's when you calculate the Be into the equation.

For instance, I have a location with Port Speed of 384kbps, CIR 128kbps and MinCIR 64kbps. Your map-class shaping would be something like:

map-class frame-relay FRTS

frame-relay cir 128000

frame-relay mincir 64000

frame-relay bc 16000 <-- this is from (128000 * .125)

frame-relay be 32000 <-- this is from (384000 - 128000) * .125

Therefore, without Be, you are only sending 16kbps per TC (125ms) while with Be, you would send 48kbps per TC.



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