From: grayt@Software.Mitel.COM (Tom Gray)
Newsgroups: comp.dcom.cell-relay
Subject: Re: Curious attitude ...
Date: 30 Jul 92 12:54:29 GMT
Organization: Mitel. Kanata (Ontario). Canada.

In article <ntlg9qc@rhyolite.wpd.sgi.com> vjs@rhyolite.wpd.sgi.com (Vernon Schryver) writes:
:In article <12430@janice>, grayt@Software.Mitel.COM (Tom Gray) writes:
:> ...
:> Now the LAN  industry itself is rapidly accepting ATM. This
:> industry expects ATM to supplant existing protocols by
:> 1995. This is occuring because of the intractable management
:> problems with the multitude of existing protocols. ATM
:> is seen as the means for creating a workable network
:> management system. I refer you to the paper
:> Conquering Complexity by John Hart of 3Com which
:> is in the proceedings of the 1990 IEEE Local Computer
:> Network Conference which makes these points. 
:> 
:> To repeat the point, the manufacturers of LAN equipment
:> regard ATM as the near term technology for their 
:> business. Does this make a point that ATM can be
:> used profitably and efficiently for LAN problems.
:
:Your first sentence may be close, that ATM will supplement, not
:supplant, other LAN protocols by 1995, but you're off the beam for the
:rest.
:
:The reason we care (I work for a company in "the LAN industry") about
:ATM is that it may be faster and cheaper than FDDI and HIPPI.  FDDI is
:only 100Mb/s, and HIPPI will not have the cost advantages of high
:volume production that the telephony guys might (or might not) give
:ATM.
:
:In no way will ATM ever "supplant" ethernet.  Ethernet will is the
:"Model A" or "Model T" of LAN's.  It is too simple and reliable and
:robust and common.  Ethernet will survive just as the Model A out
:lasted the Pierce Arrow or the Cord, either of which any reasonable
:person would prefer.
:

You know something, I agree with you. Ethernet is simple and common.
However an Ethernet can be fully loaded by 6 to 10 workstations.
Thus the problem for systems larger than just a few workstations
is not LAN connection but LAN interconnection. With the power of
work stations increasing this number can be expected to decrease.

Now ATM is seen as the answer to the interconnection problem
since it offers a chance to create a workable network modelk  that
can be used to effectively manage a data network. In this view
ATM will be used intially as a cloud network to eliminate
the complexity of the routing protocols.



:You restricted the issue to Local Area Networs.  I have no idea how ATM

No I did not. I pointed out that ATM is being designed to
create multi-service applications. A previous poster said
that ATM was only another link layer for connecting LAN's.
I disagreed with him and pointed out the use of ATM for
LAN interconnection.

:will do in wide area or metropolitan networks or for telephony.  I
:think ATM will be more popular in new networks than FDDI in 5 years
:(i.e.  1997), but ATM is not a sure bet.  There are hard and unresolved
:issues in putting data over ATM circuits.  The existing demo
:installations are actually quite discouraging.  If you look only at how
:those installations work, without being very generously hopeful about
:future developments, you would write ATM off as a bad idea, and stick
:to HIPPI.
:
:
:> Voice has been carried in statistically multiplexed networks
:> since the 1950's. These networks have well known problems
:> of absolute delay, delay skew, delay jitter etc. which
:> make them unsuitable for creating multiservice networks.
:> Data networks such as the Internet work with routers which
:> are far too costly and unreliable to provide adequate
:> voice service.
:> 
:> Now voice can be carried over the Internet if the requirements
:> aren't particularly demanding in terms of performance and
:> cost. My Ford Tempo can carry packages but no one would
:> use it in the long haul transport business.
:
:Gee, do you work for a phone company?
:There is not enough of technical substance in those paragraphs.  You
:would be more convincing if you omitted the propaganda.  There are
:problems with using "statistically multiplexed networks", but isn't the
:current telephone network a "statistically multiplexed network"?



No the telephone network is not statistically multiplexed. There 
are major problems of absolute delay, delay jitter, delay skew
etc in statically multiplexed networks. These problems must be
addressed in order to practically provide a multi-service
environment. Now ATM does offer solutions to these problems.
So  the ATM LAN will be created for the multi-service
environment.

Now the problems are well known and the ATM solutions are
becoming well known. What are the competing solutions to
these problems?
:
:> ...
:> Additionally ATM is being designed to provide for
:> protocols that can optimize the use of bandwidth. It
:> is being designed so that adaptation layers can be
:> provided to supply load smoothing (Fast Reservation,
:> String, Burst Announcing etc.). 
:
:This is not the consensus of the experts on congestion problems in
:networks carrying bursty traffic.  The IETF guys have been laughing at
:the simplistic, peak-bandwidth allocating or hopeful algorithms (as in
:"hope it works out") used by the telephony ATM guys.
:
:Congestion avoidance and recovery are hard.  There has been a lot of
:hard though and (much more important) a lot of experience in the
:Internet.  No one knows how wide area ATM networks will work for
:data.
:
:
:> ... 
:> As I have pointed out before ATM is not just a link layer protocol.
:> It is a family of protocols that are being designed to create
:> multi-service facilities that can be deployed practically.
:> As I have pointed out, it is now the protocol of choice for
:> the LAN industry which expects ATM to supplant existing
:> protocls by 1995.
:
:
:The "LAN industry" expects no such thing.  That statement is only a
:political slogan of the "ATM industry".  You'd be more convincing if
:you would not simply repeat party lines.  I took the OSI-ISO pledge to
:see ISO protocols replace TCP/IP in 1983.  History has proven that
:silly and naive.  "ATM will supplant existing protocols by 1995" is
:more obviously silly than the ISO stuff ever was.  The ATM guys don't
:even have a GOSIP to waive!
:
:It is obvious that new FDDI, token ring, and ethernet hardware will be
:sold for existing networks in 1995.  It is obvious that new ethernets
:will be created in 1995, if only because the cost of an ethernet today
:is about $180/station.  How much will the smallest ATM switch cost in
:1995?  Less than $30,000?  How much will an adapter cost in 1995?
:Maybe about $2500 if you're lucky?
:
:Get real!
:

I didn't make the prediction of the 1995 date. This prediction was made
by the representatives of the LAN industry at last years LCN
conference. They did make much of the issue of cost. Except that
the cost models they used were much more practical then the
simple "my box is cheaper than your box" model used above.
The true costs of running a traditional data network is in the
cost of maintaining it. These data networks are set up as
"PAY ME LATER" systems. They are cheap to install but
very expensive to maintain. The problem with these LAN protocols
is not in the access but in the internetworking applications.
It is here that ATM is now replacing the existing networks.
Frame Relay has seen widespread acceptance and Frame Relay
is the first example of ATM protocols.
-- 
i.sinature