RE: Distance Objectives: 2nd motion
- To: stds-802-3-hssg-distance@xxxxxxxx
- Subject: RE: Distance Objectives: 2nd motion
- From: "Thirion, Walt" <wthirion@xxxxxxxxxx>
- Date: Mon, 28 Jun 1999 10:16:08 -0500
- Sender: owner-stds-802-3-hssg-distance@xxxxxxxxxxxxxxxxxx
The Speed ad hoc has pretty much narrowed it down to either 10.00 Gb/s
or 9.58 Gb/s with a slight bias towards exactly 10.
We have had some discussion about leaving it open for other speeds, but
there has been very little discussion beyond that.
Level One Communications
> -----Original Message-----
> From: owner-stds-802-3-hssg-distance@xxxxxxxxxxxxxxxxxx
> [mailto:owner-stds-802-3-hssg-distance@xxxxxxxxxxxxxxxxxx]On Behalf Of
> Chang, Edward S
> Sent: Monday, June 28, 1999 6:34 AM
> To: Jonathan Thatcher; stds-802-3-hssg-distance@xxxxxxxx
> Subject: RE: Distance Objectives: 2nd motion
> So far we are proposing distance numbers which are basically
> numbers we can pin down eventually.
> The question is we have two speeds on the table; namely, 10
> Gbps and 2.5
> Gbps. What speeds we have in mind for those distance
> proposals? Since
> two speeds are 1 to 4 ratio , a big difference, logically we
> should have two
> groups of distance proposal, one for 2.5 Gbps and another for 10 Gbps.
> Otherwise, it seems our strategy is to pick distance first, then fit
> whatever technologies?
> Ed Chang
> -----Original Message-----
> From: Jonathan Thatcher [mailto:jonathan@xxxxxxxxxxxxx]
> Sent: Friday, June 25, 1999 7:38 PM
> To: stds-802-3-hssg-distance@xxxxxxxx
> Subject: Distance Objectives: 2nd motion
> Assuming general agreement on my first proposed motion (or
> maybe even if
> not): there are several, potential interesting distances that
> are candidates
> (there may be more, but this seems to be an adequate list to
> start with):
> 1. 100 meters over MMF (850 and 1300)
> 2. 300 meters over MMF (850? and 1300?)
> 3. 500 (550) meters over MMF (850? and 1300?)
> 4. 3 km over SMF (1300)
> 5. 5 km over SMF (1300)
> 6. 10 km over SMF (1300)
> 7. 20-40 km over SMF (1300)
> 8. 80-120 km over SMF (1500)
> To sort through these, I think we need to consider some of
> the "traditional"
> assumptions/arguments/positions that were used in Gigabit
> Ethernet when
> making decisions about fiber, wavelength, and distance:
> a. We should support the existing infrastructure (meaning the
> existing cable
> b. We should minimize the number of PHY choices
> c. We should minimize the cost of implementation
> There is a corollary to "a." (called a' = "a prime") which
> is: we should try
> to go as far as we went at slower speeds over the same media.
> Let me start with 4, 5, and 6. Since we currently specify 5 km in the
> 1000BASE-LX standard, according to "a.", we should support at
> least 5 km.
> Using this assumption, we would eliminate 4. To the best of
> my knowledge,
> all the LX solutions in existence support 10 km (these parts
> typically meet
> the Fibre Channel 10 km solution while running at the GbE speed),
> effectively making "a" a 10 km requirement
> Debatable issue 1 is therefore: support the LX distance as
> specified or as
> commonly implementable in the industry (5 or 6).
> Questions about 7 are most interesting if the group picks 6
> over 5 but could
> be independent, I will assume the former. We are all aware
> that solutions to
> the 10 km LX actually run at much greater distances because of the
> conservatism of the standard. We therefore see practical
> applications that
> achieve 20 to 40 km. These are not guaranteed to be interoperable.
> Debatable issue 1a is therefore (assuming issue 1 selects 6
> over 5): support
> the LX distance as commonly implementable or as available in
> the industry (6
> or 7).
> Questions about 8 are similar to those of 7 when taken
> independently. Most
> arguments supporting 7 would also apply to 8. The major
> rationale for doing
> either would be to take what are now proprietary solutions
> and make them
> interoperable. If members believe that the market for these
> solutions will
> be significant for 10 gig, then there will be interest in making these
> solutions interoperable (standards based). If not, this will
> continue to be
> a custom space.
> Debatable issue 2 is therefore: How interesting is this
> potential market
> space. Is it sufficient to create a standard?
> 1, 2, and 3 are significantly more difficult. Especially
> since we do not yet
> know if we can support assumption "a." without significantly
> impacting "c."
> (I can barely imagine the flurry of opinions on this topic).
> We also don't
> know where the majority opinion will go with respect to
> specifying new fiber
> types (e.g. high bandwidth MMF). In short, it might not be possible to
> satisfy both "a" and "c" simultaneously to the convincing of
> 75% of the
> Debatable issue 3 is therefore: what gives first "a" or "c"?
> There is more that can be said here, but I have a more
> important idea I
> would like to convey.
> I would recommend the following: first, conclude the 1st
> general motion on
> space per my previous append. The second section on that
> motion will help to
> the members to resolve what they are going to do about about
> the debatable
> issues here. The third portion of that motion does not impact this
> discussion, since connection to the WAN can be accomplished with any
> distance solution.
> Next, bring forward a main motion that is easily passable and
> covers the
> least controversial components of 1 through 8. I recommend a
> selection of 4,
> 5, or 6. (assuming you think that only one of the three will
> be kept (see
> "b")). Each can be placed in the motion text with the intent
> to select only
> one. Votes can be taken from least to most likely to succeed
> to see where
> the 75% vote can be achieved.
> Note: This technique is frequently used in discussions of
> allocation of
> money: "We move to collect from the membership ($0, $100,
> $1000, $50,000,
> $1,000,000) to be given to the HSSG chair to use at his
> discretion." You
> vote starting with the $1,000,000 and continue down the list
> till you reach
> 75% consensus, then stop. This is simpler and faster than
> picking a single
> number and having it amended to death. The 0$ is, of course,
> silly here
> because if something higher than or equal to $100 is not
> passed, the motion
> failed anyway.
> Then make a motion(s) to add a line(s) to the previous
> objective (now a
> passed motion) that includes something about 1 through 3. Given the
> diversity of the group, a more general motion has a greater chance of
> success than a more restrictive motion. An overly general
> motion ("do the
> best you can on MMF") has no chance. The same technique could
> be used as
> above (support a distance of at least (100, 300, 550) meters
> over multimode
> fiber). I am assuming here that the group will want to have some MMF
> solution (see "a") and will therefore pass at least 100
> meters. Note that
> this motion would set the lower bound!
> Make a motion to add to the previous objective a direction to
> or not investigate the use of higher BW MMF.
> Make a motion to add to the previous objective support of a 1550 nm
> Make a motion to add to the previous objective support of a
> longer distance
> 1300 nm solution.
> Explain the process and content of each motion to the group prior to
> starting. This way the membership will understand when the
> appropriate time
> is to discuss/amend the motion (i.e. per the above process,
> the chair would
> consider out of order any amendment and/or discussion during
> the initial
> motion on LW, SMF, that relates to MMF as this would be covered in a
> subsequent motion). The only problem is, I think, that
> someone might think
> that at this point of the process the HSSG should investigate
> more potential
> solutions than should be supported in the end. If so, then add another
> motion that adds a line to the objective to limit the number
> of solutions to
> N in the final standard.
> I am suggesting this process because I believe that we must
> exit the process
> with an objective on distance, which is the mission of this
> ad-hoc. I am
> optimistic that this or a similar procedure would accomplish
> that goal.
> There are alternatives to this which would be simpler and quicker (for
> instance, a single motion that contains the correct wording
> to allow it to
> pass with 75% vote). The problem is, if that vote fails, we
> got nuthin' and
> that ain't acceptable.