From: Roberto Fernandez (rofernandez@us.telefonica.com)
Date: Wed Jun 07 2006 - 15:21:18 ART
Friends,
Well... checking into 7.2 question of Version 3 WB, it is not a question
about FRTS it is about policing.
With FRTS Bc is bits, but with policing is Bytes, thus 128 kbits/4 = 32
kbits => 4K Bytes
The answer says
Police cir 128000 bc 4000
Best Regards,
Roberto
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brian McGahan
Sent: Tuesday, June 06, 2006 9:45 AM
To: Godswill Oletu; Leigh Harrison; Andi Bennett
Cc: ccielab@groupstudy.com
Subject: RE: FRTS Lab 1 - 7.2 question.
> I think it has to do the value of the default 'Tc' (the Tc value used
when
> none is supplied) which is 125ms.
In this case yes, but not always. The default Tc is a function
of the CIR. The higher the CIR the lower the maximum (and default) Tc.
Change the "frame-relay cir" value in a map-class with no other values
configured and look at the "show traffic-shape" output. As the CIR goes
up you will see the Tc go down.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Godswill Oletu
> Sent: Tuesday, June 06, 2006 7:23 AM
> To: Leigh Harrison; Andi Bennett
> Cc: ccielab@groupstudy.com
> Subject: Re: FRTS Lab 1 - 7.2 question.
>
> LH,
>
> Maybe, you are talking about 'fragments' which are in bytes,
otherwise,
> 'CIR' are in bits/second; 'Bc' in Bits and 'Be' in Bits.
>
> I think it has to do the value of the default 'Tc' (the Tc value used
when
> none is supplied) which is 125ms.
>
> Be=(AR- CIR) * Tc/1000
> =(128000 * 125/1000
> =16000
>
> 1/4 Be = Be / 4 = 16000/ 4
> = 4000
>
> My only problem is that, the orignal posted mentioned 'Bc' instead of
> 'Be'.
> I do not see how 'Bc' will result in a Burst, except I am missing
> something
> here or in the question. 'Bc' simply tell us how much need to be
> transmitted
> per timing interval to conform to our 'CIR'; which is in our case
every
> 125ms and to conform to our 'CIR' of 128K, that value is 16000. 'Be'
tell
> us
> that, after fulfilling our allocated quota and we have room, how much
> above
> CIR should we Burst?
>
> Since, the Access Rate (AR) was not given in the task, it is safe to
> assume
> that 'AR' is equal to 'CIR', making both 'Bc' & 'Be' to be equal and
1/4
> of
> Be will be 4000.
>
> Please, set me straight if I am missing something here.
>
> Thanks.
> Godswill Oletu
>
>
> ----- Original Message -----
> From: "Leigh Harrison" <ccileigh@gmail.com>
> To: "Andi Bennett" <bigandibennett@yahoo.com>
> Cc: <ccielab@groupstudy.com>
> Sent: Tuesday, June 06, 2006 6:39 AM
> Subject: Re: FRTS Lab 1 - 7.2 question.
>
>
> > Hey there Andi,
> >
> > CIR is in bits, Bc is in bytes
> >
> > 128,000 / 4 = 32,000 _bits_ per interval
> >
> > 32,000 / 8 = 4,000 _bytes_ per interval
> >
> > Hope that helps a bit,
> >
> > LH
> >
> > Andi Bennett wrote:
> > > Dear group.
> > > Being a bit crap at FRTS can somebody explain the answer to the
Lab
> 1
> 7.2 question.
> > >
> > > 128K CIR and allow for 1/4th for burst.
> > >
> > > How does this come up with bc = 4000 ?
> > >
> > > Am I missing something here?
> > > Cheers
> > > A.
> > >
> > >
> > >
> > > Send instant messages to your online friends
> http://uk.messenger.yahoo.com
> > >
> > >
>
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