Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: Data rate standards vs internal switching standards

Roy Bynum wrote:

> Rohit, et al,
> What is to prevent some unscrupulous vendor from sell a non WAN/MAN support
> capable version of 10GbE to someone?  Are we to be responsible for adding to
> the "caveat emptier" atmosphere of this industry?  As it is, a lot of the
> sales and marketing people in this industry have the habit of advertising
> and sell functionality that they do not have.  Are we to become part of
> that, by creating a "cheap" version of a protocol that causes support
> problems for customers?


I'm not aware that Gigabit Ethernet, Fibre Channel, IBM ESCON(TM), etc. are
perceived as "cheap" protocols. On the contrary, my perception is that they are
very cost-effective protocols, much more so than their WAN counterparts. I have
pointed out in a previous note that LAN and SAN links of significant distance
(up to 10's of km) are widely deployed in LAN and SAN applications.

Relative to customer support problems: the Gigabit Ethernet Physical Layer is
heavily based upon the Fibre Channel Physical Layer, which in turn is heavily
based upon the ESCON Physical and Signaling layers. I have personally worked on
all three. Most of the same facilities to provide link fault detection as well
as protocols capable of providing fault tolerance and isolation exist in all
three. Most mission critical transactions in the USA and a very large portion
worldwide still employ ESCON channels for reliable data transport with 100% data
integrity and zero downtime. Whatever part of a transaction goes out on a WAN is
still guaranteed by protocols at a higher level than the optical transport. I
can make a pretty good case for GbE and its follow-on, 10 GbE being as reliable
as ESCON and far more cost effective (primarily due to volume).

Just because the LAN and SAN camps approach customer support from a different
viewpoint than does the WAN camp, please don't jump to the conclusion that their
solution is inferior. It is CLEARLY orders of magnitude more cost effective. I
know that I don't fully understand the WAN solutions for reliable data
transport, but I am interested in a serious discussion of the inadequacies of
Ethernet in meeting customer support objectives.

> The whole reason for the proposal of a 9.584 MAC transfer rate was to allow
> the standardization of an optical 10GbE protocol that has the support
> functionality that is recognized by the optical networking industry.  There
> are several people on this reflector that are also participants in the
> Optical Interoperability Forum (OIF) that was started by data communications
> vendors, among others.

Many very experienced and highly respected 802.3 members have proposed several
solutions to 10 vs. 9.58464 MAC/PLS rate objective.
Recently, Ariel Hendel of Sun has proposed a 10 Gbps rate solution along with a
variable IPG. I consider this to be a reasonable compromise (not my best choice)
to settle this outstanding objective. I have still not heard any good technical
reasons as to why this solution would not work. Would you care to offer clear,
succinct reasons to this effect?

P.S. My choice is to use 802.3x flow control between the two rates and configure
the network to prevent/minimize packet loss.

> I joined this group for the specific purpose of preventing the spread of an
> optical protocol that belonged on copper, not on fiber.  I have no issue
> with 10.0 MAC transfer rate for copper, it can not be implemented of 100s
> and 1,000s of km where the user/customer does not have viability or ability
> to support he fiber that he is using.  Any protocol that can be implemented
> over optical fiber can and will be used over fiber that is leased, not
> owned.  That means it can not be supported without built in OAM features in
> the protocol.  Those features are a REQUIREMENT as far as I am concerned.

My interpretation of the statement above is that you disagree with all current
HSSG objectives since those objective do not currently support any copper
variant. Is this true?

Ethernet has supported optical PHYs of significant distance at data rates of 10
Mbps, 100 Mbps and 10 Gbps. It is only natural that optical PHYs of similar
distances are specified for 10 Gigabit Ethernet. In addition, based on
Ethernet's expanding markets, it is appropriate to extend optical PHY distances
for 10 GbE. This is clearly reflected in the 10 km and 40 km singlemode fiber
optical PHY HSSG distance objectives.

SONET OAM features have never even been proposed as a possible candidate as an
HSSG objective. I would suggest that if you're interested in this functionality,
that you make a formal presentation at the September HSSG meeting. My best
judgement is that the functionality of SONET OAM features can more cost
effectively be met by standard Ethernet features such as Management and

> The use of 9.584 transfer rate has been proposed as the most cost effective
> and simplest way to provide a base for adding OAM features to the optical
> PHYs of 10GbE.  It leverages the existing SONET/SDH technology.  It may be
> that some vendors would like to be able to have their intellectual property
> be part of the 10GbE standard.  As a data network architect, designer,
> implementor, and customer, I would rather see a public domain standard.

The simplest, most cost effective and open means of providing 10 Gbps Ethernet
transport is by leveraging all that Ethernet is and doing it ten times faster.

> Thank you,
> Roy Bynum
> MCI WorldCom
> Rohit Sharma wrote:
> > I concur entirely.
> >
> > "KISS" and make up...
> >
> > -rohit
> > Rohit Sharma
> >
> >
> > > -----Original Message-----
> > > From: Mike Bennett [mailto:mjbennett@xxxxxxx]
> > > Sent: Thursday, August 05, 1999 12:46 PM
> > > To: IEEE HSSG
> > > Subject: Re: Data rate standards vs internal switching standards
> > >
> > >
> > >
> > > I think its time the WAN folks consider a call for interest
> > > to do the SONET
> > > compatible standard separately from the LAN/MAN efforts.
> > > This would allow
> > > consensus for a 10 Gbs MAC and we could move on.  Devendra
> > > Tripathi alluded
> > > to this yesterday, although to give it an "honorable mention"
> > > rather than
> > > make it standard.  I'm curious if others would support a
> > > separate effort in
> > > hope that both groups could move forward.  I'm not opposed to a WAN
> > > standard, but it seems as though there is no end in sight for
> > > a compromise,
> > > that is to choose either a 10 or Gbs data rate.  Some seem to be
> > > willing to sacrifice the simplicity and low cost of Ethernet
> > > to get into
> > > the WAN market.  In my humble opinion as an end user of
> > > Ethernet equipment,
> > > if we stray from that which has made Ethernet so successful to date it
> > > would negatively affect the future of Ethernet.
> > >
> > > Mike Bennett
> > >


Best Regards,

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