Hi,
All a fecn/becn is a threshold that the provider sets at a certain limit to
trigger these messages when they have a certain amount of traffic on the
network.
Different providers set these threshold at different levels. The fecn/becn
does not mean anything will be dropped, only the DE packets generally can be
dropped if the network needs to drop anything.
Let me set up a hypothetical example using the number 50 and 100 packets.
Just using these numbers to make it easier to explain.
Let's say you buy service from Provider A and Provider B.
Both are the same CIR/PIR and everything about their network is exactly the
same. Let us say that the providers guarantees that they will always send
50 packets a second. also, let us say that they will send up to 100 packets
a second if the bandwidth is available but they will be marked DE.
And let us say you avg a hypothetical continuous 65 packets a second and
both providers have plenty of room to keep giving you the ability to burst
up to 100 packets/sec. However, provider A sets the fecn/becn threshold at
60 and provider b sets it at 70.
>From A, you will always get fecn and becn messages and from b, you will not
because it never reaches the 70 threshold.
That is it. From both providers, you always run the risk of having any
packets from 51-100 dropped but that has nothing to do with the fecn/becn
bits. But by looking at the fecn/becns, we get an illusion that provider a
has more congestion on their network then provider b even though you are
getting the same exact service.
hope this helps,
Paul
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=18523&t=18444
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