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Re: Assumptions




This note is more of a level-set rather than a comment to help keep us on
track... For the sake of argument... and not a statement of endorsement of
any speed or WAN transport option.

Thus far, Speed ad hoc discussion has identified two speeds, 10 Gbps
Ethernet payload and SONET OC-192 transporting Ethernet payload. I'd like to
point out that the Copper ad hoc led by Chris Diminico has proposed a 2.5
Gbps alternative on 100 meters of Cat 6 UTP. This gives us three speed
proposals for the multi-gig MAC.

Seperately, Paul has added an additional multi-gig PHY to the set of
alternatives to support the WAN on Etherenet which I have also not
considered previously. This seems to leave us with the following schemes for
Ethernet transport from LAN to WAN:

1) Legacy: 10Gbps Ethernet switched/bridged/routed to Sonet. We simply need
to specify a 10 Gbps PHY to make this fly.

2) SONET-based PHY: A new Ethernet PHY compatible with OC-192 SONET that
connects directly to the Ethernet MAC, which runs at SONET OC-192 rates.
This is the new PHY suggested by Paul. Looking forward, the next higher
Ethernet speed variant would likely be OC-768.

3) 10 Gbps Ethernet WAN PHY: A new Ethernet PHY supporting WAN dark fiber
and/or DWDM equipment, sans SONET. I believe that this is one of the options
proposed by Bill St. Arnaud among others.

Lots of options, lots of choices.

--

"Thirion, Walt" wrote:

> Ok, for the sake of argument let's go down the path of a direct
> connection to the sonet ring. Not being a Sonet expert (or even very
> knowledgable beyond a rough idea of the speed and physical topology), is
> there anything else besides the speed that would have to be put in place
> in order to directly connect the ethernet MAC to a Sonet phy?
>
> For example, would 802.3x flow control work as is or is there some other
> signaling that would have to be incorporated between the MAC and the
> Sonet PHY?
>
> Walt
>
> > -----Original Message-----
> > From: pbottorf@xxxxxxxxxxxxxxxxxx [mailto:pbottorf@xxxxxxxxxxxxxxxxxx]
> > Sent: Wednesday, June 16, 1999 5:08 PM
> > To: Thirion, Walt
> > Subject: RE: Assumptions
> >
> >
> > Walter:
> >
> > Yes, I would like to attach the 10 GigE PHY directly to a SONET ring
> > without a switch. The switch would just translate 10 GigE to
> > something else
> > and reverse the process on the other side making the network
> > more complex
> > than it needs to be. It also requires two link protocols. One
> > 10 GigE and
> > the other directly coupled to SONET. This is why ATM is still
> > alive and
> > well in the WAN. It is the shipping data link which directly
> > couples to
> > SONET. It is the only available solution for the legacy WAN
> > connection today.
> >
> > Paul
> >
> > At 07:06 PM 6/16/99 -0500, you wrote:
> > >
> > >Are you suggesting that ethernet traffic will be carried
> > directly over
> > >Sonet rings, i.e. the ethernet MAC hooking to a Sonet PHY directly
> > >connected to the ring? If so, I hadn't thought of it in that manner.
> > >
> > >I assumed the 10G ethernet would be switched/bridged/routed
> > to the Sonet
> > >ring and, therefore, the switch/bridge/router could easily absorb the
> > >minor differences in speed.
> > >
> > >Walt
> > >
> > >> -----Original Message-----
> > >> From: owner-stds-802-3-hssg-speed@xxxxxxxxxxxxxxxxxx
> > >> [mailto:owner-stds-802-3-hssg-speed@xxxxxxxxxxxxxxxxxx]On
> > >> Behalf Of Paul
> > >> Bottorff
> > >> Sent: Wednesday, June 16, 1999 4:33 PM
> > >> To: 'stds-802-3-hssg-speed@xxxxxxxx'; Thirion, Walt
> > >> Subject: Assumptions
> > >>
> > >>
> > >>
> > >> Walter:
> > >>
> > >> Certainly traditional Ethernet has used 10X speed increases
> > >> on a base 10.0
> > >> clock speed. In the early days of Ethernet there was no
> > >> compelling reason
> > >> to use any other speed since the network was clearly limited
> > >> in extent by
> > >> CSMA/CD.
> > >>
> > >> The issue of speed in MAN and WAN applications is an issue of
> > >> interoperation with SONET networks and with pure DWDM Optical
> > >> networks. The
> > >> issue of interoperation with SONET is not a telco issue. The
> > >> IETF's PoS
> > >> systems is based on using a SONET rate. The OIF is working on
> > >> a data link
> > >> for the MAN based on SONET rates. These groups are
> > certainly not telco
> > >> groups. In the wide area SONET is a major part of the
> > installed base.
> > >> Matching the SONET data rate allows leveraging the existing
> > >> installed base.
> > >> Photonic networks of today are built using SONET optical
> > >> components and
> > >> system engineering. Though future Photonic DWDM networks
> > >> could adapt to a
> > >> different data rate, they also must support SONET,
> > therefore the most
> > >> desirable system is one where the data rate of 10 GigE and
> > >> matches OC-192
> > >> allowing both to be carried over a data independent DWDM
> > >> Optical Network.
> > >>
> > >> If the data rates are not matched it will be impossible to
> > >> carry 10 GigE
> > >> over a single OC-192 wavelength. Without the ability to migrate the
> > >> installed base the MAN and WAN will be compelled to use other
> > >> technologies
> > >> then 10 GigE as a general data transport.
> > >>
> > >> I guess we can get by with two speeds for 10 GigE one for LAN
> > >> applications
> > >> and one for MAN applications.
> > >>
> > >> Paul
> > >>
> > >> > Ok, let's see if we can get the discussion started.
> > >> >
> > >> > My take from the interim is that the major discussion point
> > >> is whether
> > >> > the speed should be ~10 Gb/s or exactly 10 Gb/s. Ethernet has
> > >> > traditionally moved in orders of magnitude, 10 Mb/s, 100
> > Mb/s, 1000
> > >> > Mb/s. This speed is measured at the MAC. The physical
> > layer was free
> > >> > to to whatever necessary. For example, 1000Base-X
> > provided 1000 Mb/s
> > >> > at the MAC, but was 1250 Mb/s on the physical medium due
> > to 8B/10B
> > >> > encoding.
> > >> >
> > >> > My impression is the long haul telco camp wants the speed
> > >> to match the
> > >> > speeds currently being used for Sonet, etc. The assumption
> > >> is that it
> > >> > will be easier to interconnect ethernet networks with
> > the WAN if the
> > >> > speeds are the same.
> > >> >
> > >> > Is this the correct starting point?
> > >> >
> > >> > Walter Thirion
> > >> > Vice President, Strategic Technology Development
> > >> > Level One Communications
> > >> > 512-407-2110
> > >> >
> > >> >
> > >> Paul A. Bottorff, Director Switching Architecture
> > >> Bay Architecture Laboratory
> > >> Nortel Networks, Inc.
> > >> 4401 Great America Parkway
> > >> Santa Clara, CA 95052-8185
> > >> Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
> > >> email: pbottorf@xxxxxxxxxxxxxxxxxx
> > >>
> > >
> > >
> > Paul A. Bottorff, Director Switching Architecture
> > Bay Architecture Laboratory
> > Nortel Networks, Inc.
> > 4401 Great America Parkway
> > Santa Clara, CA 95052-8185
> > Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
> > email: pbottorf@xxxxxxxxxxxxxxxxxx
> >

--

Best Regards,
Rich

-------------------------------------------------------------
Richard Taborek Sr.    Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect         Fax: 650 940 1898 or 408 374 3645
Transcendata, Inc.           Email: rtaborek@xxxxxxxxxxxxxxxx
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Palo Alto, CA 94303-4305    Alt email: rtaborek@xxxxxxxxxxxxx