Re: Why an optical PHY makes 10GbE a non-LAN protocol

[Roy Bynum <rabynum@xxxxxxxxxxx>]

Drew,

I concur.  The only caveat is that carriers want to continue to encourage
innovation as well.  Setting hard interoperability standards too soon, or at too
low of a level, will tend to stifle innovation.  Developing technologies such as
DWDM and optical networking will probably probably continue to be proprietary
within their own end to end domain for a while.  This kind of environment is
what encourages companies like yours to develop technology as you have, and have
a potential market for it.

Roy Bynum
Optical and Data Network Technology Development
MCI WorldCom

"Perkins, Drew" wrote:

> This is partially true, but becoming less so over time. I think the key
> reason for the phenomenon that you notice is the result of regulation and
> deregulation. Remember that not too many years ago the WAN space was
> dominated by a single vendor, or perhaps one per country. Everything could
> be proprietary then. The LAN space on the other hand was invented in the
> deregulated free-enterprise world. Over time, the WAN world has been moving
> in that direction, but it takes time. So, while service providers tend to
> buy from one or two vendors if only to make their networks more manageable,
> they really want interoperability and the ability to buy from multiple
> vendors.
>
> Drew
> ---------------------------------------------------------
> Ciena Corporation                 Email: ddp@xxxxxxxxxxxx
> Core Switching Division                 Tel: 408-865-6202
> 10201 Bubb Road                         Fax: 408-865-6291
> Cupertino, CA 95014              Cell/Pager: 408-829-8298
>
> -----Original Message-----
> From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> [mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of Bruce
> LaVigne
> Sent: Tuesday, June 29, 1999 8:42 PM
> To: Perkins, Drew
> Cc: 'rtaborek@xxxxxxxxxxxxxxxx'; 'rabynum@xxxxxxxxxxx'; 'HSSG'
> Subject: Re: Why an optical PHY makes 10GbE a non-LAN protocol
>
> Drew,
>   I think I am hearing another differentiation as well (correct me if I
> am wrong): it seems that in the WAN/MAN space, more customers buy their
> setup from a single vendor, so proprietary things like FEC, coding
> schemes, wavelength, WDM, etc. are less of an issue; whereas in the
> LAN space, many customers may have multiple vendor's equipment, and
> expect them to interoperate flawlessly (not that they always do ;-)
>
> As such, the LAN standards are very stringent about the physical
> interface, so that adhering to the standard should mean your equipment
> interoperates -- plug one end of a cable into vendor A's device, and
> the other end of the same cable into vendor B's device, and they work.
> While there are proprietary "value adds", it's not usually at the PHY layer.
> For example, a vendor may have a 1000Base-LX or SX or CX interface, but
> there are few (if any) optical GE devices using a different coding
> scheme than 8B10B, or WDM, etc. -- in the LAN space.  I am hearing that
> in the WAN space, it is much more "anything goes" since a single vendor's
> equipment will probably be on both ends of the cable.  Is this a correct
> assessment?
>
> -Bruce LaVigne
>
> "Perkins, Drew" wrote:
> >
> > I think that we need new terms. I don't know what they should be, but
> > LAN/WAN/MAN/SAN/xAN are too overloaded. The critical difference between
> LAN
> > and WAN has never been just the distance between two communicating
> > endpoints. As I said previously, I believe the critical differentiator is
> > whether or not the protocol has tools to allow a 3rd party service
> provider
> > provide a managed L1 transmission service between two points.
> >
> > Even if Gigabit Ethernet is being used over private fiber end-to-end
> across
> > Canada, that doesn't mean that it has the tools that many service
> providers
> > want in order to provide an easily-managed, robust communications service.
> >
> > Drew
> > ---------------------------------------------------------
> > Ciena Corporation                 Email: ddp@xxxxxxxxxxxx
> > Core Switching Division                 Tel: 408-865-6202
> > 10201 Bubb Road                         Fax: 408-865-6291
> > Cupertino, CA 95014              Cell/Pager: 408-829-8298
> >
> > -----Original Message-----
> > From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> > [mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of Rich
> > Taborek
> > Sent: Tuesday, June 29, 1999 3:32 PM
> > To: rabynum@xxxxxxxxxxx; HSSG
> > Subject: Re: Why an optical PHY makes 10GbE a non-LAN protocol
> >
> > Roy,
> >
> > I know that you have made several arguments to the point that Gigabit
> > Ethernet is
> > not a LAN because of its 1000BASE-LX variant which supports extended
> > distances. I'd
> > like to respond with some relevant history which I am personally familiar
> > with:
> >
> > Way back in 1988 or so (+ or - one year) I was working at IBM designing
> > mainframe
> > channels. One of the neatest products I've had the opportunity to work
> with
> > at the
> > time was a 3044 Channel Extender. This product consisted of two physical
> > boxes, one
> > connected to the Bus and Tag cables of a mainframe channel interface, the
> > other
> > connected to the Bus and Tag cables of the first in a series of peripheral
> > devices,
> > other devices being daisy chained to the first device. A fiber optic cable
> > connected
> > the two 2 3044 units. In this fashion the existing 120 meter Bus and Tag
> > cable limit
> > could be extended to 2 km over 62.5 um MMF and 3 km over 50 um MMF. The
> line
> > rate
> > was 200 Mbps, the encoding was 8B/10B, and the transmitter was an LED. The
> > 3044 was
> > an excellent technology evaluator for IBM's current fiber optic-based
> > mainframe
> > channels dubbed ESCON (TM). ESCON channels, first introduced in 1990 and
> the
> > current
> > workhorse, use the same basic PHY but different framing than the 3044
> > channel
> > extended. One other significant addition is that ESCON channels also
> > supported a
> > laser-based PHY variant, extending the supported ESCON distance to 20 km
> > with a 1300
> > nm laser source. Up to three links could be arranged in line through two
> > switches,
> > forming a 60 km link between mainframe channel to peripheral.
> >
> > Other LAN protocols like FDDI supported similar extended LAN distances.
> > Fibre
> > Channel broke the 1 Gbps barrier with a completed standard in 1994,
> > supporting
> > distances of up to 10 km in ANSI X3.230-1994 (FC-PH). The GbE 1000BASE-X
> PHY
> > is
> > based upon the FC-PH PHY.
> >
> > The point in all the prior rambling is the GbE was not the first to
> venture
> > into the
> > extended LAN (call it MAN or WAN, whatever) space. Other proprietary or
> > standard
> > solutions may have gotten there earlier than even the 3044. I'm sure that
> > the IEEE
> > 802.3 has no shortage of communications systems historians.
> >
> > Existing LAN and SAN data communications protocols including Ethernet, FC,
> > HIPPI,
> > FDDI have done more than extremely well at meeting the needs of the
> > environments for
> > which they were designed from a cost, functionality, reliability,
> > manageability,
> > operations, serviceability, configuration flexibility, salability (I could
> > go on and
> > on) point of view. The WAN marketplace, and perhaps the MAN marketplace as
> > well, is
> > new and unfamiliar territory to many from the LAN and SAN community.
> >
> > I don't find it altogether unreasonable, that given the proper
> requirements,
> > guidelines, and historical perspective, that 10 Gigabit Ethernet can
> > assemble a
> > standard that addresses all LAN and extended LAN environments as did its
> > predecessors as well as venturing into the MAN and WAN space while
> > simultaneously
> > providing compatibility with all of the existing MAN and WAN
> infrastructure.
> >
> > What's wrong with the above picture?
> >
> > --
> >
> > Roy Bynum wrote:
> >
> > > ... (text deleted)
> >
> > > A WAN protocol has the ablity to work over extended distances;
> > > a LAN protocol does not.  Does full duplex 802.3 have the ability to
> work
> > over
> > > extended distances?
> > >
> > > This is a door that has already been opened.  802.3 was altered into an
> > extended
> > > distance, WAN, protocol by making it full duplex.  It may not have been
> > the
> > > intention of the 802.3 WG to do so, but that is what was accomplished.
> > Adding
> > > an extended distance PHY sanctioned 802.3 for use over extended
> distances,
> > > either over privately owned facilities, or over commercial services
> > facilities.
> > >
> > > I simply want to point out that what was accomplished by the 802.3 WG
> was
> > > greater than what they intended.  They opened the extended distance,
> WAN,
> > market
> > > place to Native data, 802.3.  This is going to have more of a major
> impact
> > on
> > > long haul data communications that it will have on the LAN environment,
> > which
> > > already has Native data, 802.3.  The over all long term result will be
> > lower
> > > cost data communications over extended distances, WANs as well as LANs.
> > >
> > > Thank you 802.3 WG,
> > > Roy Bynum,
> > > MCI WorldCom
> > >
> > > Drew Perkins wrote:
> > >
> > > > Roy,
> > > >         I believe that the difference between LAN and WAN (including
> > MAN)
> > > > protocols has been mentioned in another very recent note. The key
> > difference
> > > > is whether or not it is the same administration that owns and operates
> > both
> > > > ends of the communication as well as the media in between. This is
> > typically
> > > > the case with LANs. WANs, on the other hand, are typically owned,
> > operated,
> > > > and managed by a service provider. Because the service provider needs
> to
> > > > have good tools to know when they are not providing good service, and
> to
> > > > locate the problem causing bad service, and to restore service while
> > there
> > > > is a problem, WAN protocols tend to have facilities to provide
> superior
> > > > OAM&P compared with LAN protocols. Flavors of Ethernet do not
> currently
> > have
> > > > the mechanisms for providing these tools.
> > > >
> > > > There may also be significant differences between MAN and WAN
> protocols.
> > In
> > > > both the SONET/SDH worlds and DWDM worlds, the protocols used over
> MANs
> > and
> > > > WANs may differ significantly. MAN protocols are often built to favor
> > > > simplicity and performance over efficiency. Hence the use of UPSRs.
> WAN
> > > > protocols are more often built to favor efficiency over simplicity and
> > > > performance due to the significantly higher costs. Hence the use of 4
> > Fiber
> > > > BLSR.
> > > >
> > > > Drew
> > > > ---------------------------------------------------------
> > > > Ciena Corporation                 Email: ddp@xxxxxxxxxxxx
> > > > Core Switching Division                 Tel: 408-865-6202
> > > > 10201 Bubb Road                         Fax: 408-865-6291
> > > > Cupertino, CA 95014              Cell/Pager: 408-829-8298
> > > >
> > > > -----Original Message-----
> > > > From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> > > > [mailto:owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx]On Behalf Of Roy
> Bynum
> > > > Sent: Sunday, June 27, 1999 6:15 AM
> > > > To: Peter_Wang@xxxxxxxx
> > > > Cc: stds-802-3-hssg@xxxxxxxx
> > > > Subject: Why an optical PHY makes 10GbE a non-LAN protocol
> > > >
> > > > Peter,
> > > >
> > > > I have been trying to figure out what the distinction between a LAN
> > protocol
> > > > and
> > > > others.  There was the "assumption" made with the development of
> > 1000BaseLX
> > > > that the
> > > > moderate power and 13xx wavelength specification would made it a MAN
> > > > protocol. It
> > > > did not, it only opened the door for it to no longer be a LAN only
> > protocol.
> > > > In
> > > > optical networking with optical PHYs, there is no such thing as a
> > distiction
> > > > between
> > > > a MAN and a WAN protocol, only between LAN and non-LAN protocols.
> > > >
> > > > In re-thinking the distiction between the protocols that are
> restricted
> > to
> > > > short
> > > > distances, and those that are not, I may have found the answer.
> Direct
> > > > responce
> > > > protocols, such as ESCON have a specific acknowledge responce time on
> > each
> > > > data
> > > > block.  The transaction concurrency responce time of ESCON resticts it
> > to a
> > > > limited
> > > > distance.  The IBM standard has some specific distance limitations to
> > it.
> > > > That
> > > > specific distance limitation, based in data block acknowledge responce
> > time,
> > > > limits
> > > > ESCON to being a LAN standard.  Changing the PHY by making it optical
> > with
> > > > high
> > > > launch power will not make into a WAN protocol, because the limitation
> > is
> > > > not in the
> > > > PHY, it is in the protocol itself.
> > > >
> > > > Because of the latencies involved with the slow responce time of end
> > systems
> > > > and
> > > > mulitiple segments linked with repeaters, the original 802.3 did not
> > have
> > > > restrictive frame acknowledge responce times.  At the time, 802.3 was
> > > > distance
> > > > limited by the distances of coax cable. When full duplex 10BaseT came
> > into
> > > > being,
> > > > 802.3 became a point to point protocol, not much different from any
> > other
> > > > point to
> > > > point protocol.  Some vendors even developed optical conversion and
> > bridge
> > > > interfaces that were optical.
> > > >
> > > > When 802.3 was increased to full duplex 100 mb speeds and given an
> > optical
> > > > PHY, the
> > > > distance limitations were offically removed.  Full duplex 100BaseSX is
> a
> > > > non-LAN,
> > > > point to point protocol.  Some people even implemented 100BaseSX as in
> a
> > MAN
> > > > configuration using optical wavelength converters.  Only economics and
> > > > access to
> > > > long distance fiber prevented 100BaseSX from becoming a WAN protocol
> at
> > the
> > > > very
> > > > first.  Full Duplex 1000BaseLX offically gave sanction to non-LAN
> 802.3.
> > > > With
> > > > optical wavelength converters, even 1000BaseSX does not have any LAN
> > > > distance
> > > > limitations.  Only the "assumption" that 802.3 was a LAN protocol did
> > not
> > > > allow the
> > > > 802.3 WG to reconize that they were creating a non-LAN standard.
> > > >
> > > > The lack of restrictive frame acknowledge responce timers will also
> make
> > > > serial
> > > > optical 10GbE a non-LAN protocol by default.  Optical amplifiers will
> > allow
> > > > implementations of 10GbE that will go at least 600km.  In the optical
> > > > networking
> > > > environment there is no difference between a MAN or WAN at the
> protocol
> > > > level.
> > > > Because of physical installation limitations, multi-fiber, parallel,
> > MMF,
> > > > 10GbE may
> > > > be a LAN only implementation.  In spite of the "assumption" that 802.3
> > is a
> > > > LAN
> > > > protocol, serial optical 10GbE will not be.  Serial optical 10GbE will
> > be a
> > > > MAN/WAN
> > > > protcol.
> > > >
> > > > Thank you,
> > > > Roy Bynum,
> > > > Optical and Data Network Technology Development
> > > > MCI WorldCom
> > > >
> > > > >
> >
> > --
> >
> > 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              http://www.transcendata.com
> > Palo Alto, CA 94303-4305    Alt email: rtaborek@xxxxxxxxxxxxx