From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Fri Apr 16 2004 - 12:49:28 GMT-3
Karim,
In policing with the rate-limit statement if Bc = Be, there
effectively is no Be. If you set the Bc to be the CIR/8, you are
setting the policing interval to be 1 second. If traffic is sent in
large bursts this may result in excess delay for the traffic.
Be is used to go into debt for further intervals. Unlike
shaping, where credit is accumulated, credit in policing is borrowed
from later intervals. Again this is only used if you are exceeding the
Bc per interval.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
> -----Original Message-----
> From: Karim [mailto:karim_ccie@hotmail.com]
> Sent: Friday, April 16, 2004 4:59 AM
> To: Brian McGahan
> Cc: Karim
> Subject: Re: Police/ rate-limit parameters concept confusion
>
> Brian,
>
> I hope you have time (I know you don't have;)) to answer my original
> question. If required to have a peak of 1/4 the CIR it would affect
the bc
> value to be 128000/(4*8), which gives a rate-limit command as follows:
> rate-limit output 128000 4000 4000 conform-action transmit
exceed-action
> drop
> By the way, what does it mean setting bc equals to be ??
>
> My question was, when do I need to just leave the bc as 128000/8 and
set
> the
> be value to have busrt (bc + (CIR in bits/4)) ?????
> The thought that to have burst over the CIR, you have always to set
the bc
> equals the cir/8 and set the be value equals to bc + (whatever needed
> value
> for burst), please correct me !!
>
>
> Waiting for an answer,
> Karim.
>
>
>
> ----- Original Message -----
> From: "Brian McGahan" <bmcgahan@internetworkexpert.com>
> To: "Yasser Abdullah " <yasser@alharbitelecom.com>; "Richard Dumoulin"
> <richard.dumoulin@vanco.es>; "Karim" <karim_ccie@hotmail.com>;
> <ccielab@groupstudy.com>
> Sent: Thursday, April 15, 2004 10:20 PM
> Subject: RE: Police/ rate-limit parameters concept confusion
>
>
> It's actually in bytes per interval. By setting the Bc you are
> setting the interval length.
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987 x 705
> Outside US: 775-826-4344 x 705
>
>
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Yasser Abdullah
> > Sent: Thursday, April 15, 2004 9:53 AM
> > To: 'Richard Dumoulin'; 'Karim'; ccielab@groupstudy.com
> > Subject: RE: Police/ rate-limit parameters concept confusion
> >
> > Its in Bytes/sec.
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Richard Dumoulin
> > Sent: Thursday, April 15, 2004 5:23 PM
> > To: Yasser Abdullah; 'Karim'; ccielab@groupstudy.com
> > Subject: RE: Police/ rate-limit parameters concept confusion
> >
> > So a 1 second interval is assumed ? Or the Burst is in Bytes/second
?
> >
> > -----Original Message-----
> > From: Yasser Abdullah [mailto:yasser@alharbitelecom.com]
> > Sent: jueves, 15 de abril de 2004 16:02
> > To: 'Karim'; ccielab@groupstudy.com
> > Subject: RE: Police/ rate-limit parameters concept confusion
> >
> >
> > Karim,
> >
> > First thing to remember when policing, burst is in Bytes (unlike
> > Traffic-shaping). So if the ask you to allow a burst of 1/4 128K
> (which
> > is
> > 32000 bits/sec) then you just need to change the burst size into
> bytes.
> > That
> > mean 32000/8 = 4000 bytes.
> >
> > HTH,
> >
> > Yasser
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Karim
> > Sent: Thursday, April 15, 2004 12:55 PM
> > To: ccielab@groupstudy.com
> > Subject: Police/ rate-limit parameters concept confusion
> >
> > Hi Group,
> > Required to limit the ICMP traffic to 128K and allow a burst of 1/4
of
> > this
> > rate (128000).
> >
> > The offered solution:
> > using Rate-limit is:
> > access-list 100 permit icmp any any
> > !
> > interface Ethernet0/0
> > rate-limit output access-group 100 128000 4000 4000 conform-action
> > transmit
> > exceed-action drop
> >
> > Using MQC:
> > class-map match-all icmp
> > match access-group 101
> > !
> > policy-map icmp
> > class icmp
> > police 128000 bc 4000 conform-action transmit exceed-action drop OR
> > police
> > 128000 4000 4000 conform-action transmit exceed-action drop !
> > access-list
> > 101 permit icmp any any interface fa0/0 service-policy output icmp
> >
> >
> > I know that 4000 is taken from 128000/(8*4). I am confused, why it
was
> > solved as above, I was thinking to solve as follows:
> >
> > My solution:
> > Using rate-limit:
> > access-list 100 permit icmp any any
> > !
> > interface Ethernet0/0
> > rate-limit output access-group 100 128000 16000 20000 conform-action
> > transmit exceed-action drop
> >
> > Parameters calculated as follows:
> > bc= 128000/8 = 16000. And for busting to 1/4 the 128K, set the be=
> > 16000 +
> > (16000/4) = 20000.
> >
> >
> > Using MQC with the same previous parameters:
> > class-map match-all icmp
> > match access-group 101
> > !
> > policy-map icmp
> > class icmp
> > police 128000 bc 16000 be 20000 conform-action transmit
exceed-action
> > drop !
> > access-list 101 permit icmp any any interface fa0/0 service-policy
> > output
> > icmp
> >
> >
> > Can someone help, why didn't we use the second solution and why is
it
> > wrong
> > ????????
> >
> >
> >
> > Thanks for your help,
> > Karim.
> >
> >
>
This archive was generated by hypermail 2.1.4 : Mon May 03 2004 - 19:48:48 GMT-3