Yakov's creation of Tag Switching was Cisco's response to my architecture for the UUNET DS3 backbone which used a layer of Cascade frame switches under the routers to provide a transit fabric richer and more complex than could be managedwith pure IP-level routing. That's one of the principle bogositiesin MPLS - it uses IP-only routing technology to produce thepaths, and that's the part which is busted in the first place.

Note that MPLS itself - the forwarding mechanism - is an L2 technology, and the miscreants trying to build "MPLS VPNs" are basically doing a very lame job of simulating the Cascade frame relaytechnology.

Again, tag switching (renamed "MPLS" when the IETF decided itneeded to mark its territory) was created as a way to try andreplace the L2 switches used in UUNET's backbone. Later theframe switches were transparently replaced with ATM switchesbecause for this purpose, ATM and Frame are isomorphic.

UUNET is now using MPLS as a transit technology simplybecause nobody is doing OC192 Frame Relay as such. The storyof LDP vs RSVP signalling is pretty entertaining as well. LDPwas created as a red herring, thrown to IETF to keep it busygnawing on a harmless bone while the people who actuallyunderstood the (limited) utility of MPLS simply got on withusing it.

The fact it's been turned into some kind of Frankenstein monster("It's a dessert wax! No, it's a floor topping!") is somewhatentertaining if you like black comedy, but at the same time it'san amazing waste of effort.

More importantly, as long as I'm venting, the IETF has largelybecome a negative force for progress because it's busy promulgatingall kinds of happy horseshit which has been created to salve theego of the participants, not to solve a problem people really have.The result is that new routers must implement all kinds of crapwhich will never be debugged because it will never get used inany serious way. But it's still in there festering, reducing thereliability of the boxes and increasing the brittleness of thenetworks built with those boxes.

Of course the vendors like this virulent featuritis - it gives them new things to hawk. To me, though, it's like going to your doctor and he says, "The drug salesman was just here and he has this really amazing new drug, so I'd like you to contract this rare disease so I can cure you!"

The vendors are solving problems they want the customers to contract; they are not solving the problems customers have, and the IETF is an extremely willing participant in this.

Finally, I've been saying for many years that the "IP-ONLY" crowd is the 21st century version of the "Flat Earth Society". They insistthat the networks have only an IP layer and a completely degenerateLayer 2 below that, and then wonder why trying to fix everything atLayer 3 turns out to be exponentially complex. This IP-only 3G thingis a great example of leading people down the primrose path, verypossibly to destruction. Running an RF-based network requires aLOT of local knowledge ("local" in the sense of link-specific) andIP has proven itself incapable of the task more than once.

Applications don't mind that the IP packets got carried by a goodL2 infrastructure (that's what switched ethernet is all about), but they do mind if an IP-only infrastructure does a bad job ofdelivering most of the packets in a timely manner with a low drop rate.

I'll shut up now, but I've grown very tired of seeing a simple idea get turned into an incredible mountain of bullshit. And don't get me started on "Diffserv" - another brilliant example of defeatsnatched from the jaws of victory. And worse, the MPLS and diffservpeople have gotten together to breed. Oy!

This seems to happen over and over again in technology. Something succeeds in solving a specific problem and then swarms of people descend on it, Life of Brian style, and exclaim it's the answer to everything.

A few years later, they find something new. By then, they've manage to make the previous technology turn into a big ball of hair, so they declare it a hopeless dud and move on.

Meanwhile, the folk with the original problem carry on finding the technology that meets their needs - which is why ATM is so widely deployed in carrier nets.

We wouldn't have much to write about on Light Reading if the industry wasn't so fickle. Coming to think of it, a lot of us wouldn't have jobs.