At 8:29 PM +0000 6/27/03, dre wrote: >""Howard C. Berkowitz"" wrote in message ... >> The tier concept is mostly marketing these days, although there is >> some technical basis. > >> A tier 1 provider never buys transit. It gets all its routes from >> bilateral peering arrangements. It will have a 24/7 network >> operations center, and a national or intercontinental transmission >> network, either leased or physically operated, of at least DS-3 (more >> likely OC-3 to OC-48 these days). Its non-provider customers, if it >> has them, will usually be large enterprises only -- it's really a >> wholesaler. > >while i agree wholeheartedly with a lot of the sentiment here (as >opposed to most of the other people who are guessing at possible >meanings behind the term), there is a problem you are facing when >defining your terms.
Of course. See above. It's largely marketing-speak, but there are some useful and specialized applications that rarely come up on the list, like rules for qualifying for non-exchange-point bilateral peering. *sigh* you realize, I know, that we are talking about utterly essential concepts in working in the ISP space, yet these are things that don't show up on any Cisco test I'm aware of. This is part of why an R&S CCIE isn't much initial use to a large ISP without a good deal of OJT -- although they can probably deal with customer connections. > >the problem is that everybody pays Sprint (at least according to >Sprint), but the people who "might not pay Sprint, but shhh don't >tell anyone" (aka AOL) probably pay Worldcom. Well, probably a couple more. Think of who actually runs substantial national backbones of OC-48 or better. Sprint, AT&T, Worldcom/UUNET/whatever name du jour. There are some other major regional facility providers, including the Borgs...I mean, former Baby Bells. Now, it's perfectly reasonable that a Tier 1 could outsource the transmission, especially since they have the level of clue to write enforceable physical diversity requirements. >Speaking of AOL, >where do they fit? Tier 1, 2, or 3? They don't have enterprise IP >transit customers... they aren't really a transit-AS.... but they >are arguably larger than most ISP's that consider themselves >Tier-1's. Same with MSN. I don't know that much about their internals, so I'm making an educated guess here. My recollection is that they outsource substantial parts of their transit requirements. Frankly, I'd call them much closer to an ASP than an ISP. > >so according to your definition, only Sprint is a Tier-1. I've >heard that "only Worldcom is a Tier 1" argued as well. > >there is no correct defintion for these terms.. it's kind of like >"globally scalable software solutions".... it doesn't mean anything. >it's neither a marketing branding term, or a technical term (anymore). >"Tier 1/2" is to "large ISP" as "Soft" is to "toilet paper". Nobody >sells "Rough" toilet paper.... > >You could mathematically look at routing table data and see who is >"more of the center of the Internet"... CAIDA and most Universities >do this kind of research all the time. If this were the case: >UUNet comes out way ahead... followed by Sprint, AOL, and other >big guys. > >I prefer to think of it roughly: Worldcom, Sprint, Level-3, AT&T, >C&W, NTT/Verio, and MFS are Tier-1's. AOL, Earthlink, etc are >mostly "Dial Tier-2's", while Qwest, XO, and SBC are "DSL Tier-2's" >and Adelphia, COX, and Comcast are "Cable Tier-2's". But there >are also other important people that fit in both categories, or >mirrored-size, but different name categories. If you want to go this route, than we really need to introduce categories beyond ISP. You have major access providers/broadband aggregators/dial wholesalers. You have application service providers, which blurs with content provider. For that matter, you have wholesale content delivery providers like Akamai. > >MSN is kind of a "Dial/DSL Tier-2" + "Content Provider". Amazon, >Google, eBay, and Yahoo! are definitely strictly "Content Providers", >although Yahoo!Japan and SBC-Yahoo! provide some of that strange >mix again. > >There are also "regional Tier-1/2's" like Reach, Bellsouth, Telia, >Opentransit, Telstra, DTAG, China Telecom, GroupTelecom, etc... >and spin-offs like that UUNet-Kenya regional "Tier-1/2" and others >like "AT&T Canada"... or both regional *and* cable like Rogers or >ShawFiber. > >Finally, there are what I like to refer to as wanna-be's, or >have-been's.. these are companies like Cogent, SAVVIS, Broadwing, >ELI (although ELI is more like a regional provider), ICG, RCN, >Intermedia/Digex, Epoch, InterNAP.. etc. There are even some >wanna-be Content Providers like he.net (or back in the day, even >Exodus and Abovenet). > >The wanna-be's tend to pick up random customer bases -- Enterprises, >SMB's, home users (some dial here and there, some DSL here and >there, maybe throw some Cable in), and Internet users of all types. >They are also more likely to not "own" a facility or come in from >a remote POP as a Type-II telecommunications circuit. > >The most important provider for most business today is not any of >the above types, surprisingly. It's the pen-ultimate Tier-1... >the Exchange Point Provider. There has to be someplace where all >these people meet to exchange traffic and connect with circuits... >and in today's world... it's the Exchange Point. Yes and no. Now, most details are proprietary, but my impression is that more pure bandwidth is exchanged between "high-level" provider through direct private peering connections (private lines or equivalents) than through exchange point fabrics. Confusing this even further is the presence of private peerings both between the cages/racks in an exchange point (a piece of fiber), and the less visible private peerings that take place in the exchange point building but not in the exchange point proper (i.e., fiber connections down in the cable vault). There's a delicate economic balance whether bilateral/multilateral peering at exchanges gives you enough routes, and also enough economic fairness. Bill Norton has published rather extensively on this topic, and presented at multiple NANOGs. The reality is that at some (there's no rule that applies to all) exchange points, one provider may still buy transit from another and peer with yet others. Different exchange points only permit peering without financial exchange. One incentive to greater exchange point usage may be IPv6, the unicast address structure for which reserves top-level identifiers for exchange points as well as major transit providers. This would allow geographic rather than carrier-based aggregation. > >Anyone who is worth their weight in the IP world gets some metro >circuits to the nearest Exchange Point, drops a cheap router in >there, and connects to anyone they want (and changes providers at >the drop of a new "intra-building" cross-connect, or even as simple >as a router configuration change). > >But to most people, this is like buying from a discount broker or >walking into the Chicago Board Options Exchange (CBOE) and trading >on the floor. Why pay discount prices, when you can get about >30-40 middle-men involved to each take an enormous cut? > >-dre Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=71570&t=71508 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
