Pricing and Internet Architecture

Frisky070802 writes "The Politech list recently posted a pointer to a new paper (pdf) by UMN prof Andrew Odlyzko, which compares the telecom industry to the historical transportation industry (railroad, bridges, and such). One quote, from the conclusion, is particularly interesting: '... the networking industry [has] devoted inordinate efforts to technologies such as ATM and QoS, even though there was abundant evidence these were not going to succeed. One can go further and say that essentially all the major networking initiatives of the last decade, such as ATM, QoS, RSVP, multicasting, congestion pricing, active networks, and 3G, have turned out to be duds. Furthermore, they all failed not because the technical solutions that were developed were inadequate, but because they were not what users wanted.'"

Comments

Railroads...

[Pig Hogger]

I have always been interested in railroads, and as I see organizations thriving to work over large areas, I cannot fail to notice that they run in essentially the same problems railroads ran into 150 years ago when they found-out that they had to absolutely synchronize their operations over vast territories in order to simply avoid accidents...

This is one reason, for example, why Standard Timezones were adopted by the railroads, then telegraphy used to coordinate operations.

More than 100 years ago, there were elaborate protocols to insure that instructions were transmitted reliably and double-checked to insure that no error of communication occured.

Of course, the technology used (telegraph keys and, later, telephone) was not as sophisticated as now, but the essential principles (fail-safe, reduntancy checks, retransmission protocols and whatnot) were there.

It's always fun to watch young pups straight out of school try to solve a problem that was solved more than a century ago by the high-tech industry of the times: the railroads...

Re:Railroads...

[Animats]

There are two pre-electronics technologies that anyone designing reliable systems should understand in some detail - railroad signalling and telephone switching. Both were designed to be more reliable than their components. In the relay era, that was essential, because component reliability was mediocre by modern standards.

The references you need to read are obscure, but exist. For railroad signalling, the technology was mature by 1930. An understanding of either General Railroad Signal or Union Switch and Signal relay-era technology is useful. Both companies produced good books describing their technologies in 1924. There's also "NXSYS", a simulator down to the relay level of New York City subway signalling technology. The key idea to take away from railroad signalling is what "fail-safe" really means and how it is consistently implemented.

Telephony in the relay era is best understood by studying its most advanced form, Number 5 Crossbar. There are descriptions of the technology in "A Technical History of the Bell System". #5 Crossbar is a transaction-oriented system, in which units of different types do quick transactions to get the job done. Resources of a given type are interchangeable, so losing one unit just reduces call capacity. Resources include originating registers, markers, senders, trunks, translators, billing punches, and trouble recorders. The switch fabric itself is dumb; all the smarts are in the resources. Resources are never tied up for the duration of a call; they're seized from a pool, used for a fraction of a second to a few seconds, and released. That architecture is extremely reliable; no Bell System central office in the relay era was ever down for more than 30 minutes for any reason other than a natural disaster. The key idea to take away from telephony is how interchangeable resources were used to build up a system.