From: Filyurin, Yan (yan.filyurin@EDS.COM)
Date: Thu Jun 21 2007 - 00:26:53 ART
Never mind, I figured it out, after reading up some more on it, but I
must say shape average vs. shape peak is the biggest QOS mystery!
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Filyurin, Yan
Sent: Wednesday, June 20, 2007 4:19 PM
To: ccielab@groupstudy.com
Subject: Help with concept explanation
I know this comes in the discussions every month, but I think there is a
difference in how Cisco Documentation describes it vs. how some authors
describe it.
After reading a few examples in the practice labs, I saw that if I were
given a frame relay traffic shaping requirement that would be something
like this.
A circuit has access rate of 1024kbps and PVC provisioned at 512kbps and
configure the connection to not go above the CIR, but if enough credits
have been accumulated be able to burst up to the port speed.
Frame Relay traffic shaping is pretty straightforward, assuming TC of
1/8 of a second.
Frame-relay map-class shape
frame-relay cir 512000
frame-relay bc 64000
frame-relay be 64000
There could be numerous alternative solutions either using frame-relay
traffic, rate, generic traffic shaping or class based shaping. And the
one thing, I am not clear on is why in case of Class Based traffic
shaping the configuration involves shape peak.
Class class-default
shape peak 512000 64000 64000
If I understand how shape peak works, the token bucket will effectively
be BC + BE, which would be in case on frame-relay traffic shaping, but
in case of shape peak BC + BE will go into bucket every time interval
and won't it be different from frame relay shaping configuration
Would shape average be more appropriate.
I know everyone is sick of this discussion, as it keeps constantly
appearing and I thought I understood this well, but this seems to go
against it.
Also Cisco documents it differently that Wendell Odom's book.
Yan
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