10-23-2006 07:08 PM
Can somebody explain :
Frame relay CIR
Minumum CIR
Bc
Be
Tc
I heard Tc is fixed 125 Ms now we can calculate Bc=Tc*CIR
But how to calculate Be=??is it CIR/8.
10-23-2006 11:14 PM
Hi
some explainations below, hope they help.
CIR (Committed Information Rate) The average rate at which you want to transmit.
This is the rate at which you want to send in periods of noncongestion.
MinCIR (Minimum CIR) The minimum amount of data to send during periods of congestion. This is usually what you get from the telco. MinCIR defaults to one-half of CIR.
Bc (Committed Burst) The amount of data to send in each Tc interval.
Be (Excessive Burst) The amount of excess data allowed to be sent during the
first interval once credit is built up. Transmission credit is built up during periods of nontransmission. The credit is the burst size. Full credit is typically CIR / 8.
Tc (Committed Rate Measurement Interval) The Bc / CIR time interval. The time interval shouldn?t exceed 125 ms (almost always 125 ms).
Interval Bc / CIR. The maximum is 125 ms, or 1/8 second.
10-24-2006 01:20 AM
Hello,
in addition to the other post, have a look at this link as well, which is (I think) an excellent presentation on Frame Relay Traffic Shaping:
Understanding Frame Relay Traffic Shaping
http://www.internetworkexpert.com/resources/01700368.htm
Regards,
GNT
10-24-2006 03:17 PM
In follwing configuration
Map-class frame-relay MYCLASS
frame-relay cir 192000
frame-relay bc 24000
frame-relay be 24000
frame-relay mincir 128000
frame-relay adaptive-shaping becn
By default Be value is =0 when Be=Bc or Be=2Bc In some examples .So what does it mean this value depends upon what.
10-24-2006 10:48 PM
Even though your config gives a Be value, it has to be earnt first. Your right with respect that Be defaults at 0 and this value will go up and down as you use your link.
The less you use your circuit the more credit that is built up so the more bursty traffic you will be able to send during your more busier periods (above the guarenteed rate (minCIR)).
HTH
Stu
10-25-2006 02:17 AM
The TC is only 1/8 or 125ms for circuts below 650k. This value is reduced as the circuit speed increases.
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