RE: [EFM] Network timing?
Bob,
Actually, there is probably be going to be very little market for T1/E1
over Ethernet. In spite of the confusion being created by the "shared
service infrastructure" people, the actual market is the other way around.
Thank you,
Roy Bynum
At 09:21 PM 9/26/01 +0100, Bob Barrett wrote:
>Roy,
>
>Actually what I think is needed is the reverse of ITU X 86 i.e. E1/T1 over
>Ethernet. The ietf have some rfcs on this with an IP layer of course. I have
>a proposal for E1/T1 over Ethernet / 802.3 only, but I am not sure which
>forum would be interested (if any). As I said in an earlier email today, it
>is much easier to carry T1/E1 over a side band than it is to packetise and
>de-packetise it. However, one benefit of packetising it is that it can be
>carried through a layer two or an IP metro / core network, all the way to
>the switch (given constant latanct of course, I think we went round that
>loop about six weeks ago).
>
>Bob
>
> > -----Original Message-----
> > From: owner-stds-802-3-efm@majordomo.ieee.org
> > [mailto:owner-stds-802-3-efm@majordomo.ieee.org]On Behalf Of Roy Bynum
> > Sent: 26 September 2001 17:51
> > To: Frank Coluccio; Matthew.Beanland@xxxxxxxxxxxxxx
> > Cc: stds-802-3-efm@ieee.org
> > Subject: Re: [EFM] Network timing?
> >
> >
> >
> > Framk,
> >
> > One of the interesting side features of a "side band" type of OAM, is the
> > simplistic ability to support "network timing" if the service requires
> > it. Personally, I do not think that E1/T1 interfaces at the CPE Demark
> > will be much of an issue. There is already a simple standard for mapping
> > Ethernet frames into T1/E1 payloads, ITU X.86.
> >
> > Thank you,
> > Roy Bynum
> >
> > At 08:10 AM 9/26/01 +0000, Frank Coluccio wrote:
> >
> > >Hi Mathhew,
> > >
> > >It sounds like you're desribing a variant of FDDI II's "guaranteed" T1
> > >capabilities, or some form of T1 emulation _a_la_ ATM. I've
> > discussed this
> > >possibility with others here in the past. At what "super rate"
> > (minimum entry
> > >level) of Ethernet would you propose, first, before such an isochronous
> > >approach
> > >should be considered? [Or, should it be considered at all?]
> > >
> > >In 10 Mb/s or lower, I don't think so. At 100 Mb/s or higher, a
> > >possibility, imo.
> > >What say?
> > >
> > >Frank
> > >
> > > >
> > > > Hi EFMers,
> > > >
> > > > I guess this is a question for the service providers out there.
> > > Imagining an
> > > > EFM ONU supporting bearer emulation (say, in order to provide E1/T1
> > > interfaces
> > > > for connection to a legacy PABX), is there any interest in
> > having the OLT
> > > > propagate network timing (usually 8kHz, traceable back to some
> > > reference) to
> > > > the ONUs by some method?
> > > >
> > > > Propagation of network timing is allowed for in the xDSL standards.
> > > >
> > > > Should we require propagation of network timing in EFM it could be
> > > propagated
> > > > by either the Ethernet symbol rate itself or via some coding
> > method. Some
> > > > physical layer schemes (ATM25 comes to mind) use a low spec
> > oscillator
> > > for the
> > > > line rate and insert special line tokens at 8kHz to allow user side
> > > equipment
> > > > to recover network timing if required. It would be possible
> > to use one
> > > of the
> > > > non-data 8B/10B tokens as a timing marker and send at 8kHz,
> > > alternatively if
> > > > there is an OAM block it could be sent at 8kHz rate.
> > > >
> > > > Best Regards,
> > > >
> > > > Matt
> > > >
> > > > Matt Beanland, Project Manager/Principal Architect
> > > > Telecommunications Research and Development, Fujitsu Australia Ltd
> > > > 5 Lakeside Drive, Burwood East 3151, Victoria, Australia
> > > > e-mail: matthew.beanland@xxxxxxxxxxxxxx Phone: (613) 9845 4313
> > > >
> > > >
> >