RE: [RPRWG] SendA, SendB, SendC
Anoop,
It is behaviorally different in that a (semi-) intelligent client can use
these signals to plan what to send, rather than send and hope it works.
Also, since the physical interface from the client to the MAC is not
specified, there is no guarantee that the client even knows when an attempt
to send fails.
jl
-----Original Message-----
From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
Sent: Wednesday, June 19, 2002 2:04 PM
To: 'John Lemon'; Anoop Ghanwani; 'stds-802-17@xxxxxxxx'
Subject: RE: [RPRWG] SendA, SendB, SendC
John,
That still doesn't answer my question of how this is
behaviorally different from the MAC client choosing
to heed these signals. Regardless of whether it heeds
the signals or not, the traffic will be blocked. In
that case, I don't see the need for the signals. If
it enables some kind of functionality, then I'd be all
all for it. Otherwise, were asking for something in
the MAC that's essentially redundant.
-Anoop
> -----Original Message-----
> From: John Lemon [mailto:JLemon@xxxxxxxxxxxx]
> Sent: Wednesday, June 19, 2002 2:09 PM
> To: 'Anoop Ghanwani'; 'stds-802-17@xxxxxxxx'
> Subject: RE: [RPRWG] SendA, SendB, SendC
>
>
> Anoop,
>
> I'm not enough of a token ring expert to answer your
> questions about how and
> why 802.5 works the way it does. Maybe our esteemed vice
> chair can answer
> your question about how and why 802.5's treatment of
> priorities is different
> from 802.17's usage of service classes.
>
> As for what happens if a client chooses to ignore the
> signals, the client's
> frames may not be accepted by the MAC. The send signals are a
> friendly way
> of informing the client that it has exceeded the relevant
> shaper. If it
> tries to send a packet with a Service Class value of X while the sendX
> signal is not asserted, the MA_UNITDATA.request will be refused.
>
> jl
>
> -----Original Message-----
> From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
> Sent: Wednesday, June 19, 2002 1:30 PM
> To: 'John Lemon'; Anoop Ghanwani; 'stds-802-17@xxxxxxxx'
> Subject: RE: [RPRWG] SendA, SendB, SendC
>
>
>
> John,
>
> 802.5 MACs have several priorities and the client
> can request a specific priority for its transmission.
> Why is 802.17 any different?
>
> If the client can ignore the signals, why do we
> need to have them? In other words, what happens
> different if the client ignores them versus
> uses them.
>
> -Anoop
>
> > -----Original Message-----
> > From: John Lemon [mailto:JLemon@xxxxxxxxxxxx]
> > Sent: Wednesday, June 19, 2002 1:33 PM
> > To: 'Anoop Ghanwani'; 'stds-802-17@xxxxxxxx'
> > Subject: RE: [RPRWG] SendA, SendB, SendC
> >
> >
> > Anoop,
> >
> > We need 3 such signals because we have 3 separate service
> > classes. Other 802
> > MACs do not have distinct service classes. A client is free
> > to ignore the
> > signals if does not want to use them or does not know how
> to use them.
> >
> > jl
> >
> > -----Original Message-----
> > From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
> > Sent: Wednesday, June 19, 2002 11:35 AM
> > To: 'stds-802-17@xxxxxxxx'
> > Subject: [RPRWG] SendA, SendB, SendC
> >
> >
> >
> >
> > Why does 802.17 need SendA, SendB, SendC signals
> > going from the MAC to the client? Other 802 MACs
> > do not have a similar primitive even though they
> > have to get the client to wait in order to get
> > access to the medium (e.g., in token ring LANs, a
> > station must wait until a free token arrives).
> >
> > Can anyone shed some light on this?
> >
> > -Anoop
> > --
> > Anoop Ghanwani - Lantern Communications - 408-521-6707
> >
>