RE: [RPRWG] RE: [IPORPR] payload length and padding and stuff
Anoop,
I agree with you that the draft is vague on this.
One way to approach this could be as follows:
Specify that a RPR MAC has only ONE reconciliation
layer. The service primitives can specify direction.
As a consequence, no node can have different PHYs on the east and west
therefore it is not possible to build a ring with any other phy.
raj
> -----Original Message-----
> From: Anoop Ghanwani [mailto:anoop@xxxxxxxxxxxxxx]
> Sent: Tuesday, December 03, 2002 4:03 PM
> To: 'Frank Kastenholz'; iporpr@xxxxxxxx; 'stds-802-17@xxxxxxxx'
> Subject: [RPRWG] RE: [IPORPR] payload length and padding and stuff
>
>
>
> Frank,
>
> We shouldn't be trying to mix different PHYs,
> e.g. 10GE and OC-192, since they are in fact running
> at different data rates, and having PHYs with different
> data rates on the same ring is not allowed by the
> current version of the draft. I think the draft
> is silent on this specific issue, though.
>
> I'm cc.-ing the 802.17 list since this is an interesting
> issue that has come up there as well. Maybe someone
> else might be able to shed some light on this
> (PHY people??).
>
> -Anoop
>
> > -----Original Message-----
> > From: Frank Kastenholz [mailto:fkastenholz@xxxxxxxxxxx]
> > Sent: Tuesday, December 03, 2002 3:46 PM
> > To: iporpr@xxxxxxxx
> > Subject: [IPORPR] payload length and padding and stuff
> >
> >
> > i'm editing the iporpr document and have come across a question...
> >
> > suppose i have an 802.17 ring comprised of both gig-e and sonet
> > sections. gig-e, i assume, has the usual ethernet min frame
> > size rules, so if a dataframe is transmitted onto gig-e and
> > the payload is too short, it gets padded so that the frame
> > is 64 bytes. if a frame is transmitted onto a sonet section,
> > no such padding is needed, since there are no min frame length
> > rules for sonet. so what happens when a frame that was initially
> > transmitted on a sonet section reaches a gig-e section of
> > the ring:
> >
> > +-----------+ +-----------+ +-----------+
> > | Station 1 | | Station 2 | | Station 3 |
> > +-----------+ +-----------+ +-----------+
> > / \ / \ / \
> > ...___/ \________/ \________/ \___...
> > sonet gig-e
> >
> > A frame generated at station-1 that has, let's say, only a 20 byte
> > payload, would be 42 bytes long. This is fine for sonet. What
> > happens when the frame reaches the gig-e section between stations 2
> > and 3?
> > - is the frame padded by the mac/phy layers in station 2?
> > - is the frame dropped?
> > - are the min-frame rules dropped for gig-e when it's being used
> > for .17?
> > - is it illegal to mix sonet and gig-e in the same ring?
> > - am i very confused and is the answer obvious to all but me?
> >
> > thanks
> >
> > frank kastenholz
>
>