From: Menga, Justin (Justin.Menga@xxxxxxxxxx)
Date: Sun Nov 11 2001 - 18:19:22 GMT-3
The last two parameters are actually in bytes not bytes per second...
Regards
Justin Menga CCIE#6640 CCDP CCNP+Voice+ATM MCSE+I CCSE
Network Solutions Architect
Wireless & E-Infrastructure
Compaq Computer New Zealand
DDI: +64-9-918-9381 Mobile: +64-21-349-599
mailto: justin.menga@compaq.com
web: http://www.compaq.co.nz
-----Original Message-----
From: Wade Edwards [mailto:wade.edwards@powerupnetworks.com]
Sent: Saturday, 10 November 2001 5:29 a.m.
To: Mark Lewis; ccielab@groupstudy.com
Subject: RE: OT QoS: CAR sanity check !!!
You need to realize that the first number is in bits per second and the
second and third numbers are in bytes per second.
So you are allowing 32000 bits per second normal then allowing 768000 bits
per second burst.
L8r.
-----Original Message-----
From: Mark Lewis [mailto:markl11@hotmail.com]
Sent: Thursday, November 08, 2001 7:40 PM
To: ccielab@groupstudy.com
Subject: OT QoS: CAR sanity check !!!
Guys,
I need a quick sanity check on a CAR config. Any help is much appreciated.
(1) I need to configure CAR such that each customer (as specified by a
seperate ACL) has an average rate being 32000 bps, and the peak rate being
128000 bps. Here's my config
interface serial x/y
rate-limit output access-group 101 32000 96000 96000 conform-action
transmit exceed-action drop
rate-limit output access-group 102 32000 96000 96000 conform-action
transmit exceed-action drop
.
access-list 101 permit ip any 10.1.1.0 0.0.0.255 !customer A access-list
102 permit ip any 10.2.2.0 0.0.0.255 !customer B
(This is a multipoint DS-3 i/f, and will have multiple rate-limit statement
(maybe 30+). Anybody know of a limit on rate-limit statements per i/f ?).
As I understand it, the above config will allow an average rate of 32k, and
then above 32000+96000 (normal AND excess burst) = 128k, all traffic will be
dropped.
Of course, normally only SOME (random) traffic is dropped above normal
burst, BUT because excess burst is equal to normal burst, ALL traffic will
be dropped - am I right ?
(2) There's a secondary issue here - the traffic being transmitted is TCP,
and therefore the above will cause TCP slow start (ie. there will be tail
drops). This will I suppose only occur when the aggregate traffic rises
above 128k (per rate-limit). Anybody got any thoughts on this ?
Thanks very much in advance,
Mark
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