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Re: 10GE data rate?


If I understand your comments on 2) correctly, then there needs to be some sort
of device that encapsulate the Ethernet stream before injecting into Sonet ring?
If so, other than the potential small cost advantage of this simpler device, how
does it differ from 1)?

The other issue that's not clear is exactly how will this scheme satisfy the WAN
O&M needs as stated by Roy Bynum?  Will this device have to signal the upstream
bridge on the LAN side when something happens on the Sonet side?


Martin Nuss <nuss@xxxxxxxxxx> on 06/23/99 06:14:35 AM

Please respond to nuss@xxxxxxxxxx

Sent by:  Martin Nuss <nuss@xxxxxxxxxx>

To:   Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx>
cc:   nuss@xxxxxxxxxx, HSSG <stds-802-3-hssg@xxxxxxxx>, HSSG Speed
      <stds-802-3-hssg-speed@xxxxxxxx> (Peter Wang/HQ/3Com)
Subject:  Re: 10GE data rate?

Thanks for reposting this.  Some comments:

Re: 1)

Yes, if you are willing to put a 10GE bridge at the point where you
enter the SONET PHY, you can run 10GE at 10.00 Gb/s.  Flow control etc.
will take care of the mismatch in payload data rate.

Re: 2)

We should be careful here, and I believe Paul Bottorff has pointed this
out before:  This does not need to be a SONET-based PHY.  All you need
is to keep the data rate of the 10GE PHY to 9.5846 Gb/s (that includes
preamble, SFD, Ethernet frame, and IFG).  That allows you to map 10GE
directly into an OC192c envelope without requiring a 10GE bridge and
buffering etc.  You may have some minor slack in the data rate because
of the IFG.

What I wanted to point out is that Paul Bottorff's presentation is a
good starting point for a scrambled serial 10GE framing standard that
could be used both ways:  Either standalone with all the control
features we know from 1GE (and optionally more), or mapped into SONET to
support WAN OAM features.  For the latter to happen cost effectivly, we
need to keep the data rate to 9.58 Gb/s.

Sorry if you have heard some of this before from others.  I could not
attend the Idaho meeting and am therefore not on the speed reflector.


Rich Taborek wrote:
> In an early note to the HSSG Speed reflector, I summarized my view of all
> schemes discussed thus far to support the WAN at Ethernet rates of ~10 Gbps.
> I'll repost that summary here to make it available to the larger HSSG
> reflector. The three schemes I have come up with are:
> 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.
> My scheme (3) seems to correspond with Martin's (1) and (3) below and is a
> PHY variant which supports a data rate of exactly 10.0 Gbps. Other qualities
> of this PHY may include any or all of the following:
> a) Direct drive of long-haul dark fiber and/or DWDM equipment;
> b) Simplex and/or duplex channels;
> c) Standard Ethernet facilities for out-of-band signaling and cable plant
> management including MAC Control frames, Auto-Negotiation, and (I hate to
> even suggest it) Primitive Signaling using alternate "Idle" codes. Ethernet
> out-of-band signaling capabilities are actually more extensive than most
> protocols I'm aware of.
> (1) above seems supports the existing SONET infrastructure quite adequeately
> and allows high performance switch/bridge/router products to be implemeted
> in a manner of highest compatibility with the LAN and WAN.
> (2) sabove ignificantly affects the existing LAN market through its dictate
> of SONET speeds and other peculiarities not applicable to existing LANs and
> is a step in the wrong direction .
> (3) above takes Ethernet where no Ethernet has gone before and treads
> directly on the existing WAN infrastructure. This latter alternative will be
> difficult to go forward with also since the "LAN" folks consider it to be
> outside the scope of 802, and the "WAN" folks view it as a significant
> territorial encroachment. However, once (1) happens, the cost advantages of
> it will inevitably drive implementations and products based on (3).
> --
> Martin Nuss wrote:
> > Roy:
> > I wanted to get your expert opinion on a few issues that would be of
> > interest to me as we go forward in the standard:
> >
> > 1) do you really believe that we need to support all the WAN OAMP
> > features in 10GE?  I would rather prefer a light-weight 10ge protocol
> > that guarantees the lowest cost in the LAN, but make sure that it can be
> > wrapped easily into a WAN envelope to support all the WAN features.
> >
> > 2) at the last meeting, Paul Bottorff as well as Mike Salzman presented
> > approaches to a serial 10GE standard based on scrambling as opposed to
> > block coding.  Both of these could be used for a low-cost serial LAN
> > standard, and wrapped into WAN envelopes like SONET to provide WAN OAMP
> > features.  The 10GE data rate would have to be kept to around 9.6 Gb/s
> > to make that possible at the lowest cost.  Presumably, that would
> > accelerate the acceptance of 10GE in the WAN.
> >
> > 3) Alternatively, we could propose to allow for additional control
> > fields in the 10GE standard that duplicate the functions most important
> > for WAN apps.  This may be the cleanest solution, but it will require
> > 802.3 to venture into an area that it has not worried about before...
> >
> > Any thoughts?
> >
> > Martin
> --
> 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
> 1029 Corporation Way    
> Palo Alto, CA 94303-4305    Alt email: rtaborek@xxxxxxxxxxxxx

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