From: Andy (and123and@googlemail.com)
Date: Wed Oct 17 2007 - 05:05:57 ART
Hi Darren
the router does not think in terms of 1 second, 2 seconds, 3 seconds etc, it
just sees TC1,TC2,TC3....TC22 etc. Using your initial example the router
will send at 8000 bits at TC1, 8000 bits at TC2 etc, lets say at TC12 it
does not send any bits, then in TC13 it can send (Be + Bc).
Note: If we configured Bc at 8000, and Be at 8000, then for TC1 we can send
at 16000 because for TC1 Be and Bc are given full loads, thereafter Be
bucket is only filled if there are any Bc bits unused.
hth
-A
On 16/10/2007, Darren Johnson <dazza_johnson@yahoo.co.uk> wrote:
>
> I cannot recall where I read this now. The only document I could find is
> here:
>
>
> http://www.cisco.com/en/US/partner/tech/tk713/tk237/technologies_tech_note09186a00801e32e7.shtml
>
> Check out 'excess burst' where it states "Generally, Be data is delivered
> with a lower probability than Bc, and the network treats it as discard
> eligible"
>
> I know I read about it somewhere, but cannot recall where :-(
>
> ----- Original Message ----
> From: Gregory Gombas <ggombas@gmail.com>
> To: Darren Johnson <dazza_johnson@yahoo.co.uk>
> Cc: ccielab@groupstudy.com
> Sent: Tuesday, 16 October, 2007 3:13:50 PM
> Subject: Re: Frame-relay traffic shaping.
>
> Sounds good to me - not sure about the DE bit getting automatically
> set on the BE bits though...do you have a link to that doc?
>
> On 10/4/07, Darren Johnson <dazza_johnson@yahoo.co.uk> wrote:
> > Hello all. I want to get this nailed once and for all.
> >
> > I have a serial line clocking at 128kbps. I configure
> > FRTS as follows:
> >
> > CIR = 64000
> > Bc = 8000
> > Be = 8000
> > MinCIR = 32000
> >
> > My understanding is this. I can send 8000 bits (Bc)
> > per Tc. Tc = CIR/Bc, so I can send 8000 bits every
> > 125ms. On a serial interface clocking 128kbps, this
> > means that it will take only half of the Tc to send
> > the Bc (128000/8 = 16000 bits can be sent every
> > 125ms).
> >
> > So far so good. If I don't send any data for a full 1
> > second (all 8 Tc), then I can use these for Be over
> > the next Tc(s). The next second I transmit Bc (which
> > takes half the Tc) but I can also send Be (8000 bits)
> > becuase these were not used in previous Tc(s).
> >
> > If I understand this right, if I send no data in 1
> > second, the next second I can send 16000 bits (Bc +
> > Be) for each Tc = 128kbps.
> >
> > Additionally, the Be bits get the DE set to 1 by
> > default. Is this correct?
> >
> > Hopefully someone can help confirm if I have nailed it
> > or not :-)
> >
> > Dazzler
> >
> >
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