RE: Assumptions

["Thirion, Walt" <wthirion@xxxxxxxxxx>]

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
>