RE: [RPRWG] control TTL
John,
From my recollection, there were items that affected the whole
draft, rather than specific clauses, and this was one of them.
That ad-hoc resolution group addressed this and other issues,
or so I thought. Have to ask Tom Alexander on the details.
Regardless of recollection, this number is consistent with
a past working group decision. There are painful repercussions
in having numbers set at 255, since the number of attachment
points (that can all be legally visited once) is twice the
number of stations and should be counted in the TTL field.
And, I'm most interest in what possible technical reason
could be used to justify such a large number of devices?
Particulary when each chip may be required to support
things like discovery tables. No point is having all
chips support a large theoretical maximum, when it
rarely (if ever) will be utilized.
DVJ
David V. James, PhD
Chief Architect
Network Processing Solutions
Data Communications Division
Cypress Semiconductor, Bldg #3
3901 North First Street
San Jose, CA 95134-1599
Work: +1.408.545.7560
Cell: +1.650.954.6906
Fax: +1.408.456.1962
Work: djz@xxxxxxxxxxx
Base: dvj@xxxxxxxxxxxx
> -----Original Message-----
> From: owner-stds-802-17@xxxxxxxxxxxxxxxxxx
> [mailto:owner-stds-802-17@xxxxxxxxxxxxxxxxxx]On Behalf Of John Lemon
> Sent: Tuesday, June 18, 2002 5:44 PM
> To: 'Anoop Ghanwani'; 'stds-802-17@xxxxxxxx'
> Cc: Tom Alexander (E-mail)
> Subject: RE: [RPRWG] control TTL
>
>
>
> The maximum number of stations on a ring is 255, not 127. I have no idea why
> someone changed clause 1; but clauses 8, 9, 10, 11, and E all use a value of
> 255. And the resolution of comments 155 and 431 support this. The Overview
> is informative, and is supposed to reflect a simple summary of what has been
> decided in the normative clauses.
>
> (As an aside, while I have no problem with 2000 km as a recommended limit,
> I'm also troubled that such technical changes are being made in the Overview
> instead of one of the normative clauses. The Overview should be reflecting
> what has been decided in the other clauses, not making its own decisions.)
>
> jl
>
> -----Original Message-----
> From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
> Sent: Tuesday, June 18, 2002 3:47 PM
> To: 'stds-802-17@xxxxxxxx'
> Subject: [RPRWG] control TTL
>
>
>
>
> At the last meeting I had a comment requesting more
> information on why the control TTL is 2 bytes. The
> explanation provided was that 1 byte is not sufficient
> if we have 255 stations and are wrapping. With D0.3,
> the maximum number of stations is 127. So now I
> don't see a reason for a 2-byte control TTL. I'm
> about to submit another comment for this, unless I
> can be convinced of a technical reason for a 2-byte
> control TTL.
>
> -Anoop
> --
> Anoop Ghanwani - Lantern Communications - 408-521-6707
>