Subject: Re: latest draft of guaranteed

From: [email-masked] (Fred Baker)
Date: Fri, 12 Jul 1996 18:55:00 -0700

At 4:26 PM 7/12/96, Craig Partridge wrote:
>    * I've changed some of the parameter numbers after consulting with
>    John Wroclawski about keeping parameter spaces clearly distinct.

Silly question:

When a sender sends a PATH message, how does he know that the receiver is
going to request guaranteed service? As in, how does he know

        (a) whether to put in the adspec, and
        (b) which set of names (the controlled load numbers or the
            guaranteed numbers, or some other qos spec's numbers) for the
            parameters to use?

Wouldn't it be better to make the number spaces overlap to whatever extent
they can?

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
When people run around and around in circles we say they are crazy.
When planets do it we say they are orbiting.

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From: Craig Partridge <[email-masked]>
Date: Sat, 13 Jul 96 16:03:42 -0700

Silly question:

Not silly at all....

    When a sender sends a PATH message, how does he know that the receiver is
    going to request guaranteed service?

I believe the right answer is that in the absence of a standard for supporting
multiple services concurrently (e.g. service replacement and other nasty
heterogeneity functions), the sender gets to pick which service gets used
(or advertises multiple times...)

We're actually trying to do that.  What we've done is distinguish between
common parameters and per-service specific ones.  (Common ones have numbers
below 128, per-service ones above 128).

There are a host of other messy issues lurking here.  Such as, while
the available bandwidth is a generic parameter, in the context of a
particular service, it may have different values.  (I.e., the link bandwidth
may be 100 Mb/s, but a router is configured to only allow 25 Mb/s of
guaranteed traffic on the link -- rationally, an AdSpec for guaranteed
that contained the bandwidth information would allow the guaranteed
service module to revised the bandwidth information down).

JTW's the expert on parameter naming and Lee & Scott have thought a lot
about heterogeneity and I hope they will step in if I've said anything
stupid here.

Craig

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From: Lee Breslau <[email-masked]>
Date: Mon, 15 Jul 1996 11:24:41 PDT

Craig,

> service module to revised the bandwidth information down).
I don't agree with this.  If the thing that you advertise is a function
of a particular service, then it seems to me it should be defined
as an exported parameter for that service.

In this case, bandwidth is a general characterization parameter with
some agreed upon meaning independent of any service.  It therefore
shouldn't have different values in the context of a particular service.

I know we talked in montreal about doing something consistent with
the naming of parameters across services.  But I didn't take this
to mean that parameters defined in the general characterization 
parameters document automatically have meaning in other services.

Lee