Chris Said: -----------
reasons, 1) it's still significantly cheaper than long-haul circuits of the same capacity,
Your implication is wrt publically resold managed L2 networks such as ATM or Frame Relay. My earlier comments were addressing private management of one's own L1 network using L2 ATM or FR. Not to say either of us are wrong, just to frame the comments. Sean Doran said: ----------------
My canonical explanation for this is that people are actually deluding themselves into thinking that ABR will work and the "quiet moments" across a large number of VCs can effectively be statmuxed out of existence without hurting goodput.
I attempted a large diatribe here to examine what you mean by work, but my semantical misunderstandings lead me to instead ask you: What do you mean by the statement "people .. thinking ... ABR will work"?
The apocryphal reason is that people with too much influence in carriers' decision making processes are desperately trying to gain enough revenue to justify the ridiculously large amount of money spent on deploying ATM and convincing everyone it was the way the truth and the light of the future, even if that revenue isn't as profitable as selling raw bandwidth. (cf. the canonical explanation)
I'd agree with you if you were right, Sean. However, this statement is bullocks. It's not all a conspiracy, though it makes for an interesting plot line for nanpcog. The amount of money spent on ATM research is paltry relative to the current market. ATM achieved prominence in the ISP bb for two reasons: o It worked o It was available ATM will retain prominence for some time for many reasons, some of which are: o It continues to work o It cotinues to grow in if speed o Investment in knowledge o Capital and Installation Investment o Investment in tools This stream of characters from you on how IP can do what ATM achieves is quite puzzling. Do you really, honestly think that IP has QOS built into it? My recollection of the rfcs is not eidetic, but the TOS fields aren't supported by anyone but a nonstandard marketing plan, wrong? ATM allows one to build qos and particularly granular flow modification into one's <L3 network. Additionally, the ability to measure based upon preaggregated src-dest flows is exceedingly valuable data, available from L3 routers with only a large expenditure of effort.
The only ones I can think of right off the top of my head involve the counting problem. (Modulo easy deployment of cisco's rate limiting and/or the ability to make tunnels fast).
Easy and cisco in the same sentence. Let me write this down on my web page of quotes....
Rather, I guess the question is, which of the "interesting abilities" (which I agree are interesting in a theoretical sense) are actually practically useful when running part of the Internet?
See my note from several weeks ago and comments above. -alan ps. for the record I am one of those who believe with most of my heart and not a small fraction of my unimpressive might that a ubiquitous fabric somewhere near L2 will make life good. As bw increases linearly, the interconnections will increase geometrically. Advancements in science will exponentially increase bw as the practical technology is used more commonly. I often wonder if people shouting IP IP IP are really worried about their own lack of malleability in dealing w/ other information pushing technologies. That slight jab aside, the statistical aggregation of muxing ability of one protocol is not all that greater than the other, so whether the aggregation appears at L3 or L2 should, to the best of my knowledge and experience, be fairly approximate, at least today. The downside to today's atm is the 1/ overhead and 2/ one cell/frame drop requiring all cells retransmitted by the higher layer (IP). pps. I'm really not all that in love with ATM. But it does work. If IP could do the things that ATM/FR can, then off we go. My experience and knowledge say that managing a really large, dynamic, and robust network requires more than flexibility than L1 pipes and L3 routers. Something in the middle is needed to smooth out the corners.