Cell Relay Archive

[Rich <rmavro@snet.net>]

Walt Weber wrote:

> The switches I know of will not allow you to oversubscribe CBR.  On the other
> hand, if there aren't any CBR cells being sent, VBR, ABR, and UBR can use the
> bandwidth.
>

Actually, CBR oversubscription was implemented by SNT some time ago, althoughthe
company was bought by Tellabs and I don't think they are selling those products
anymore.  It was done to support video with LANE via CBR with join-leaf/MPP.
A little off subject, but yes, it is possible to implement LANE with CBR. It
turns
out to be a useful ELAN for QoS.

Rich Mavro
VBrick Systems, Inc.


> Yu Ning wrote:
>
> > Hi friends,
> >
> > This is really an old topic, but i'm a little slow and can't catch up,:-)
> >
> > Can we over-subscribe CBR connection within a physical link? Heard some
> > expert (from C&W) last night, that at the idle time when upper layer app
> > don't generate data, so no cell will be send even in CBR conenction, then
> > the idle time in the cell level will be used by other connection, such as
> > UBR, ABR.  Is this a general practice by all the switch? Or it's only an
> > advantage of certain switch ( more capabile and efficient switch)?
> >
> > Thanks definitely for your answer, or pointer to a previous discussion
> > is also welcome. Thanks.
> >