From: Michael Snyder (msnyder@xxxxxxx)
Date: Tue Aug 20 2002 - 10:24:22 GMT-3
You mean the document that uses 3/16 x CIR = Bc and 3/8 x CIR = Be.
Who cares about Be. I've done some tests, using analogx netstat, and
windows ping -t -l 970 a.b.c.d. The netstat program gives a real per
second bit graph, and the windows ping command generates nearly perfect
1KB packets. Running multiple copies of ping generates predicable
traffic rates.
What I've seen is that Be only sets the choppiness factor of the graph,
it doesn't effect the rate. The Bc doesn't effect the rate that much
either, as long as it's greater than the mtu size of the packets.
Seeing it graphed out, is different than reading about it. When I
increased Be, the traffic peaks got larger, but the average thruput
stayed the same. When I lowered Bc, the average thruput dropped a bit,
but stayed in the same general range of the CIR setting I set.
In other words, I don't think the Bc nor Be settings will sink you in
the lab unless they give you explicit requirements for those settings.
You can download analogx netstat from www.analogx.com, When I use it, I
set the options to show traffic bit values.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Ted Richmond
Sent: Tuesday, August 20, 2002 3:15 AM
To: ccielab@groupstudy.com
Subject: Bc Be S.O.S.....
Hello group,
When I finally thought that I've got Qos under-control
(err...well say 80% undercontrol), I came across a doc
- Selecting Burst and Extended Burst Values for
Class-Based Policing
http://www.cisco.com/warp/public/105/carburstvalues.html
This one really threw me off. Here are some questions:
* Are Be,Bc definitions different for shaping and
policing?
* The above doc says, "When bc is equal to be, the
traffic regulator cannot borrow tokens and simply
drops the packet when insufficient tokens are
available". I though this is the case when be=0
* The doc gives an example with 'CIR= 1 bit/sec, Bc= 2
bytes/sec and Be=4 bytes/sec' (pkt size as 1 byte). Is
this possible? How can he send 4 packets with the
above constraints and still maintain 1bit/sec CIR?
I am totally lost now - I should've never read this
doc. Please help -S.O.S
TIA.
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:48:30 GMT-3