RE: Assumptions

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

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
>