Re: rate-limiting and mark traffic question

From: Allan Wells (wellse@bigpond.net.au)
Date: Fri Apr 09 2004 - 10:54:22 GMT-3


For policy map

The class-map match-all a
actually matched an accesslist and i had precedence being set getting late
and cut and pasted wrong info but result is accurate.
----- Original Message -----
From: "Allan Wells" <wellse@bigpond.net.au>
To: <ccielab@groupstudy.com>
Sent: Friday, April 09, 2004 11:43 PM
Subject: rate-limiting and mark traffic question

> Hello all,
> Im working on some policing/marking excercises in the lab and want to
validate
> what is the optimum method for marking and policing traffic I have tried
two
> methods described below and perhaps their are better ways. For me they
both
> work and appear to achieve the same result except with rate-limit on the
> interface the pkt size for ping was 3800bytes with policy-map only
959byte
> pkts wer successful why is this ? policy were the same for policing.
> Both use bits for cir and bytes for burst when configuring.
>
> 1. But basically my question "?" is which method should i use if asked to
> perform such a task in the lab are both methods ok or is there some
> limitation someone see's that i dont.
>
> ###################--Test 1 rate-limit and mark
> certain-traffic--##########################
>
> -----------------------------------THE-Topolgy----------------------------

---
> ------------
>
>
|PC_HOST|----------EThSegment---------R1------------frpvc-----------------R3
> 1.1.1.10/24                       .1/24   10.1.1.1/30
> .2/30
>
>
############################################################################
#
> ###############
>
> Router 1
>
>
> This first ping/s below is from host 1.1.1.10 to R3/s1 10.1.1.2 with the
> access-group 1 used with rate-limit statement(see-below) on R1.
>
> The access-ist is set for permitip host 1.1.1.9 so this source host i'm
using
> 1.1.1.10 isnt being used/effeceted by the rate-limit access-grooup blah
blah
> so traffic isnt subject to any policy and justs goes about its business
> normally : )
>
> Router1  ethernet 0
>
> interface Ethernet0
>  ip address 1.1.1.1 255.255.255.0
>  rate-limit input access-group 1 8000 1500 2000 conform-action
> set-prec-transmit 5 exceed-action drop
>  bridge-group 1
>
>
>
> Pinging 10.1.1.2 with 14000 bytes of data:
>
> Reply from 10.1.1.2: bytes=14000 time=133ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=129ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=129ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
>
> #########An access-list entry on R3 serial shows the access-list being
matched
> for ip
> #########Nothing shows for this ENTRY--->permit ip host 1.1.1.10 any
> precedence critical log
> #########BECAUSE THE ACCESS-LIST ON R1 DOESNT SPECIFY 1.1.1.10 AT THis
STAGE
>
> $$I wasnt positive if any other traffic would pass through unafected thats
why
> i did this.$$
>
> Extended IP access list 199
>     permit ip host 1.1.1.10 any precedence critical log
>     permit ip any any (970 matches)
>
> ******************************************************
> NOw I Add an access-list 1 entry ON R1 & CONTINUE THE PING---> now
policing
> and marking kicks in.
> -------------BEFORE----------------access-list 1 permit 1.1.1.9
> -----------> ADD this entry ------>access-list 1 permit 1.1.1.10 "MY-PC"
>
> Reply from 10.1.1.2: bytes=14000 time=131ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=129ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=132ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=129ms TTL=254
> Request timed out.
> Request timed out.I COULD PING WITH PKT SiZE UP TO 3800BYTES WITH SUCCESS
> Request timed out.
> Request timed out.
> ____________________________________________________________________
>
> I REDUCE the ping pkt size to 1400bytes from 14000 then go to r3 and sh
> accesslist 199
> THERE are matches against precedence entry on the access-list applied to
R3
> serial interface for me this "validates" the prec is being set by r1 for
host
> 1.1.1.10 ping packets I already know the rate-limit is working as above.
>
>
> ####Extended IP access list 199
> ####permit ip host 1.1.1.10 any precedence critical log (13 matches)
> ####permit ip any any (1 match)
>
> #################cmd window on host 1.1.1.10 ################
>
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Request timed out.
> Reply from 10.1.1.2: bytes=1400 time=22ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
> Reply from 10.1.1.2: bytes=1400 time=21ms TTL=254
>
> Ok so that work fine and I can use multiple rate-limit statments with
> different access-groups if i wanted to match other criteria
>
>
############################################################################
#
> ###############
> -------------The next test is using policy-maps to do the same
> task----------------
>
############################################################################
#
> ###############
>
> -----------------------------R1 ethernet apply policy-map
> ab------------------------------
>
> class-map match-all a
>   match ip precedence 5
> class-map match-all b
>   match any
>
> policy-map ab
>   class a
>      police 8000 1500 1500 conform-action drop exceed-action drop
>   class b
>
> Before apply policy ping test to R3
> Pinging 10.1.1.2 with 14000 bytes of data:
>
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
> Reply from 10.1.1.2: bytes=14000 time=130ms TTL=254
>
> after policy applied to eth0
>
> ##################interface Ethernet0
>  #################ip address 1.1.1.1 255.255.255.0
>  #################service-policy input ab
>  #################bridge-group 1
>
> the largest pkt allowed was 958bytes!! with rate-limit on iterface eth0 in
1st
> example above it was 3800 ! before it would fail. WHY IS THIS ?
>
> Pinging 10.1.1.2 with 958 bytes of data:
>
> Reply from 10.1.1.2: bytes=958 time=16ms TTL=254
> Reply from 10.1.1.2: bytes=958 time=15ms TTL=254
>
> SHOW POLICY-MAP INT ETH0
> ###############THE EXCEEDED BELOW PKTS WERE ALL PINGS OVER 958BYTES
#########
>
> Service-policy input: ab
>
>     Class-map: a (match-all)
>       151 packets, 154988 bytes
>       5 minute offered rate 7000 bps, drop rate 1000 bps
>       Match: access-group 1
>       police:
>           cir 8000 bps, bc 1000 bytes
>         conformed 116 packets, 106793 bytes; actions:
>           set-prec-transmit 5
> ------->  exceeded 35 packets, 48195 bytes; actions:
>           drop
>         conformed 4000 bps, exceed 1000 bps
>
>     Class-map: b (match-all)
>       0 packets, 0 bytes
>       5 minute offered rate 0 bps
>       Match: any
>
>     Class-map: class-default (match-any)
>       0 packets, 0 bytes
>       5 minute offered rate 0 bps, drop rate 0 bps
>       Match: any
>
> on R3 validate precedence with access-list matches
>
> r3#clea access-l coun 199
> Extended IP access list 199
>     permit ip host 1.1.1.10 any precedence critical log (90
> matches)<-------matching!!
>     permit ip any any (9 matches)
>
> Conclusion achieved the same thing though viewed different behaviour with
the
> ping pkt sizes
>
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