RE: QOS question

From: Eric Taylor (etaylor10@tampabay.rr.com)
Date: Sun Mar 20 2005 - 13:17:08 GMT-3


I think the violate-action should probably be set to "set-frde-transmit" as
well.

I can't confirm this but my reasoning is that we will drop the packets and
they won't be queued. I'm trying to find which order of operation happens
when policing and shaping is configured on the same pvc.

My gut instinct tells me policing.

Does anyone know?

Eric

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Eric Taylor
Sent: Sunday, March 20, 2005 10:44 AM
To: ccie2be; 'Alexander Arsenyev (GU/ETL)'; 'Oliver Grenham';
ccielab@groupstudy.com
Subject: RE: QOS question

Tim, you are correct.

PIR should be dropped from the config.

Eric

-----Original Message-----
From: ccie2be [mailto:ccie2be@nyc.rr.com]
Sent: Sunday, March 20, 2005 10:10 AM
To: 'Eric Taylor'; 'Alexander Arsenyev (GU/ETL)'; 'Oliver Grenham';
ccielab@groupstudy.com
Subject: RE: QOS question

Eric,

At the risk of reviving an old topic, I don't think there's any need to
configure a PIR.

Wouldn't this config do the trick?

policy-map SET-BE-DE
  class ip_traffic
   police cir 128000 bc 1280 be X
     conform-action transmit
     exceed-action set-frde-transmit
     violate-action drop

Where x = the difference between port speed and cir per interval.

Except for pir, I agree your config would set the DE bit on traffic
exceeding bc.

Tim

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Eric
Taylor
Sent: Sunday, March 20, 2005 8:45 AM
To: Alexander Arsenyev (GU/ETL); 'Oliver Grenham'; ccielab@groupstudy.com
Subject: RE: QOS question

Ok, I'll take a stab at this one. I'm not real sure how you would do this to
a reaction to a BECN so this is assuming that anything that hits the BE
bucket is considered congestion.

This should set the DE bit on ip traffic that hits the BE bucket. At least
that is the theory behind this config.

 class-map match-all ip_traffic
  match protocol ip
!
!
 policy-map SET-BE-DE
  class ip_traffic
   police cir 128000 bc 1280 pir 256000 be 1280
     conform-action transmit
     exceed-action set-frde-transmit
     violate-action drop
!
interface Serial1/0
 frame-relay traffic-shaping
!
interface Serial1/0.16 point-to-point
 ip address 172.16.16.1 255.255.255.0
 frame-relay interface-dlci 106
  class 256k
!
map-class frame-relay 256k
 frame-relay cir 128000
 frame-relay bc 1280
 frame-relay be 1280
 service-policy output SET-BE-DE
!

R1#sh policy-map int s1/0.16
 Serial1/0.16: DLCI 106 -

  Service-policy output: SET-BE-DE

    Class-map: ip_traffic (match-all)
      145 packets, 10736 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol ip
      police:
          cir 128000 bps, bc 1280 bytes
          pir 256000 bps, be 1280 bytes
        conformed 53 packets, 3224 bytes; actions:
          transmit
        exceeded 0 packets, 0 bytes; actions:
          set-frde-transmit
        violated 0 packets, 0 bytes; actions:
          drop
        conformed 0 bps, exceed 0 bps, violate 0 bps

    Class-map: class-default (match-any)
      53 packets, 8044 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any

R1#sh traffic-shape s1/0.16

Interface Se1/0.16
       Access Target Byte Sustain Excess Interval Increment Adapt
VC List Rate Limit bits/int bits/int (ms) (bytes)
Active
106 128000 320 1280 1280 10 160 -
R1#

Let me know what you guys think about it.

HTH,
Eric

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Alexander Arsenyev (GU/ETL)
Sent: Sunday, March 20, 2005 7:47 AM
To: 'Oliver Grenham'; 'ccielab@groupstudy.com'
Subject: RE: QOS question

Was the original question specifically stating where the congestion is
experienced: on the sending router
or in the FR network? Was there another task/question which asked to
configure FRTS?

If both answers are NO then I have to use lateral thinking:
-you can actually create permanent state of congestion on the router
interface by configuring "hold-queue 1 out" on the interface. This means
that every single IP packet will completely fill the output queue and this
is classic definition of congestion :-}
-when you are done with the above just configure "frame-relay de-list"
matching on IP traffic and attach it to the interface.
-the down side is that there will be packet drops :-[ but I guess that
original question says there is nothing about drops prevention.
HTH,
Cheers
Alex

-----Original Message-----
From: Oliver Grenham [mailto:ogrenham@optusnet.com.au]
Sent: 20 March 2005 13:25
To: Alexander Arsenyev (GU/ETL)
Subject: Re: QOS question

Hi Alex,

I understand that FRTS may be used to set DE bits but this particular
question did not ask to configure FRTS nor did it give any values foe
provisioned rates etc? I found it a difficult little question and one which
I still have not definitively solved.

Ollie.
----- Original Message -----
From: "Alexander Arsenyev (GU/ETL)" <alexander.arsenyev@ericsson.com>
To: "'Oliver Grenham'" <ogrenham@optusnet.com.au>; <ccielab@groupstudy.com>
Sent: Sunday, March 20, 2005 4:14 PM
Subject: RE: QOS question

> Frame Relay Traffic Policing sets DE bit on all traffic above Bc:
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120
limit/120s/120s17/frtp_gsr.htm
>
> <quote>
> The following actions are taken, on a per-packet, per switched PVC basis,
by Frame Relay Traffic Policing:
>
>
> --------------------------------------------------------------------------
------
>
> Step 1 If the Discard Eligible (DE) bit is set in the packet when it
arrives, the packet is automatically treated
> as excess: the Bc test in Step 2 is skipped and the packet proceeds to
Step 3.
>
> Step 2 If the DE bit is not set when the packet arrives, and the byte
count in the packet is within Bc for the past Tc,
> then the packet is allowed through. If the packet is not within Bc for the
past Tc, the packet proceeds to Step 3.
>
> Step 3 If the number of bytes in the packet falls within Be+Bc for the
past Tc, the DE bit in the header is set
> (if it is not already set) and the packet is allowed through. If the
packet does not fall within Be+Bc for the past Tc,
> the packet is dropped.
>
> </quote>
>
> HTH,
> Cheers
> Alex
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]
> Sent: 20 March 2005 03:07
> To: ccielab@groupstudy.com
> Subject: QOS question
>
>
> If for instance a question asks you to configure a router so that it sets
the
> Frame relay DE bit for IP traffic when and only when there is congestion,
how
> would one approach this question? I know you could use a frame relay DE
> list/Group but this would always set the DE bit for all packets classified
in
> the list.
>
> Any ideas would be greatly appreciated.
>
> Ollie.
>
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