The MPLS WG Archive

["Bora Akyol" <akyol@pluris.com>]

Of course overbooking is a poor man's substitute for calculating the
equivalent capacity of the traffic that is passing through the tunnel.

Nevertheless, overbooking is commonly used and people like it (for many
reasons).

Bora


----- Original Message -----
From: "Curtis Villamizar" <curtis@avici.com>
To: "Erickson Trejo-Reyes" <eenet@electeng.leeds.ac.uk>
Cc: <curtis@avici.com>; <david.charlap@marconi.com>; <mpls@UU.NET>
Sent: Tuesday, August 29, 2000 6:48 PM
Subject: Re: Fw: MPLS and CAC



>
> In message <01c01130$842fc740$dbb00b81@default.leeds.ac.uk>, "Erickson
Trejo-Re
> yes" writes:
> >
> > By overbooking you mean that, for example, if a voice source can be =
> > treated as a VBR source with 64 KB peak bit rate and activity factor of
=
> > 0.4, then the reservation should be made to a higher value than the =
> > computed effective bandwidth (and obviously higher than the average bit
=
> > rate of 0.4 times 64KB)?
>
> I meant that the allowable sum of reservations could greatly exceed
> the desireable sum of reservations.  The ingress would have to be
> smart enough to lay out trafffic such that load was well distributed
> and was far below the values where CAC would limit the sum of
> reservations.
>
> > I had thought that, if an MPLS node is due to use only certain =
> > percentage of its total capacity to serve, for example, guaranteed =
> > services, it would not be too harmful to make reservations (up to the =
> > available percentage) only based on the sustained rate, with the only =
> > possible consequence of temporary squeezing the throughput of =
> > best-effort services. Comments?
>
> Instead of limiting the guaranteed services to 30% by setting the
> reservable bandwidth very low, the ingress can be configured to avoid
> any links which are approaching or have over 30% guaranteed service.
> Right now the only way to know that it is guaranteed service and now
> BE is to give then different holding priorities but that is changing.
>
> Curtis