RE: QOS Question from Routopia LAB 3

From: Glenn Johnson (glennjohnson@xxxxxxxxx)
Date: Sun Aug 11 2002 - 13:44:20 GMT-3

   
Quoting original problem --

; Configure the serial interface on R6 so that Ping
; traffic can only
; utilize 10% of available bandwidth. Allow BGP to
; utilize no more
; than 20% of available bandwidth. Allow all other
; traffic to utilize up
; to 70% of available link capacity.

I'm _far_ from a QoS expert, but wouldn't three separate rate-limit
statements work? (you could add three more if 'input' control was an
issue as well -- something you can't do with CBWFQ, which seems limited
to output control [at least on my equip])

Assuming a 256k link for purposes of calc.

10% is 25600
20% is 51200
70% is 179200

The burst values below were calculated using the target limit/8 and then
multiplying by 1.5, and finally multiplying that number by 2.

Originally entered as:
(Conf-if)
rate-limit output access-group 101 25600 4800 9600 conform-action
transmit exceed-action drop
rate-limit output access-group 102 51200 9600 19200 conform-action
transmit exceed-action drop
rate-limit output access-group 103 179200 33600 67200 conform-action
transmit exceed-action drop

Then from sh run int fa0/0 (things get rounded)

Interface FastEthernet0/0
ip address 10.1.1.1 255.255.255.0
rate-limit output access-group 101 24000 4800 9600 conform-action
transmit exceed-action drop
rate-limit output access-group 102 48000 9600 19200 conform-action
transmit exceed-action drop
rate-limit output access-group 103 176000 33600 67200 conform-action
transmit exceed-action drop

access-list 101 permit icmp any any
access-list 102 permit tcp any any eq bgp
Access-list 103 permit ip any any

(following some intense icmp traffic)

Router#sh int fa0/0 rate-limit
FastEthernet0/0
  Output
    matches: access-group 101
      params: 24000 bps, 4800 limit, 9600 extended limit
      conformed 31 packets, 27334 bytes; action: transmit
      exceeded 3 packets, 4542 bytes; action: drop
      last packet: 14692ms ago, current burst: 6068 bytes
      last cleared 00:01:10 ago, conformed 3000 bps, exceeded 0 bps
    matches: access-group 102
      params: 48000 bps, 9600 limit, 19200 extended limit
      conformed 0 packets, 0 bytes; action: transmit
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 3233872ms ago, current burst: 0 bytes
      last cleared 00:01:10 ago, conformed 0 bps, exceeded 0 bps
    matches: access-group 103
      params: 176000 bps, 33600 limit, 67200 extended limit
      conformed 0 packets, 0 bytes; action: transmit
      exceeded 0 packets, 0 bytes; action: drop
      last packet: 3233876ms ago, current burst: 0 bytes
      last cleared 00:01:10 ago, conformed 0 bps, exceeded 0 bps

This seems to work. My question is should we go back and adjust the
burst values based on the IOS rounding of our initial numbers?

Thanks

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Michael Snyder
Sent: Sunday, August 11, 2002 11:15 AM
To: 'Jim Brown'
Cc: ccielab@groupstudy.com
Subject: RE: QOS Question from Routopia LAB 3

Ok,

In other words, both effect bandwidth.

Policing affects maximum usable bandwidth.

Shaping affects minimum usable bandwidth.

Two sides of the same coin really.

Back to the question that started the thread,

; Configure the serial interface on R6 so that Ping
; traffic can only
; utilize 10% of available bandwidth. Allow BGP to
; utilize no more
; than 20% of available bandwidth. Allow all other
; traffic to utilize up
; to 70% of available link capacity.

Would GTS tied to access lists work? I know that the S in GTS stands
for shaping, but when you tie it to an access list, it's really doing a
limiting function.

-----Original Message-----
From: Jim Brown [mailto:Jim.Brown@caselogic.com]
Sent: Sunday, August 11, 2002 10:01 AM
To: 'Balaji Siva'; msnyder@revolutioncomputer.com
Cc: ccielab@groupstudy.com
Subject: RE: QOS Question from Routopia LAB 3

Custom queueing wouldn't be appropriate based on the original question
to "limit bandwidth."

Queueing only comes into play during times of congestion. In other words
if the traffic in question is the only traffic on the wire, it can
exceed the desired limit if there isn't any congestion and custom
queueing would never come into play.

This is really the difference between policing and shaping.

-----Original Message-----
From: Balaji Siva [mailto:bsivasub@cisco.com]
Sent: Sunday, August 11, 2002 8:43 AM
To: msnyder@revolutioncomputer.com
Cc: ccielab@groupstudy.com
Subject: RE: QOS Question from Routopia LAB 3

 CAR is supported on many platforms..not just on 7500..

http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/
qos_
c/qcprt1/qcdcar.htm#xtocid285760

now as far as custom queueing solution.. i suppose it could....i am not
a big fan of legacy qos features

regards
Balaji

-----Original Message-----
From: Michael Snyder [mailto:msnyder@ldd.net]
Sent: Sunday, August 11, 2002 10:18 AM
To: 'Balaji Siva'
Cc: ccielab@groupstudy.com
Subject: RE: QOS Question from Routopia LAB 3

Hate to be simple, but couldn't custom queueing do this?

BTW, is CAR supported on the lab hardware? My voice qos book said it
could only run on the 7500 series and above. Then again it doesn't
cover class based queuing either, so it may out of date.

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Balaji Siva
Sent: Saturday, August 10, 2002 8:53 PM
To: William lu; Akhilesh Verma; ccielab@groupstudy.com
Subject: RE: QOS Question from Routopia LAB 3

the question is vague as it could be just LLQ for ping/bgp ..and the
rest class-default ..if the question had just mentioned that these
things are applicable only at times of congestion.

but since it didn't..

how about this

class-map ping

match access-group 101 <--- 101 matches icmp

class-map bgp

match access-group 102 <---- 102 matches bgp

policy-map ccie

class ping

police xxxx xxxxxx <-----10 % policer

class bgp

police xxxx xxxx <----- 30 % policer

int s0

service output ccie

Regards
Balaji

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
William lu
Sent: Saturday, August 10, 2002 9:22 PM
To: Akhilesh Verma; ccielab@groupstudy.com
Subject: Re: QOS Question from Routopia LAB 3

Hi,

I would use both technique complete this scenario:

1. Use CAR to limit the bandwidth used in CBWFQ. The
default bandwidth of physical interface be used for
the bandwidth calculation if you did not use TS or
CAR. (You may no be able to use bandwidth interface
command, which use for metric only).

2. Use CBWFQ to assign the bandwidth to each type of
traffic, which specify by CAR.

This is my implementation of the question. hope have
better one.

LUW.
Akhilesh, Where can I find this lab scenario? I'd like
to play with this completed lab.
--- Akhilesh Verma &lt;akverma@cisco.com&gt; wrote:
&gt; Folks,
&gt; I am working on Routopia LAB 3
and
&gt; I have the following
&gt; question
&gt;
&gt; Configure the serial interface on R6 so that Ping
&gt; traffic can only
&gt; utilize 10% of available bandwidth. Allow BGP to
&gt; utilize no more
&gt; than 20% of available bandwidth. Allow all other
&gt; traffic to utilize up
&gt; to 70% of available link capacity.
&gt;
&gt;
&gt; Now ordinarily One would think that this is
&gt; classification and not
&gt; policing . Would you do CBWFQ here or CAR ?
&gt;
&gt; TIA
&gt;
&gt; Akhilesh
&gt; ------------------------------------------------
&gt; ------------------------------------------------
&gt; Akhilesh Verma,
&gt; Cisco Systems Inc.
&gt; Systems Engineer
&gt; 771,Alder Drive,
&gt; Milpitas,CA-95035
&gt; Pager:800-365-4578
&gt; Direct: 408-853-9033
&gt; Mobile: 510-501-1182.
&gt; E-mail: akverma@cisco.com

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