If you limit your consideration to how things look at IP and AP/AR, then the Tier-N discussion is solvable.
If you care about actual physical facilities, all bets are off. Taking a tangent from the diversity concept: http://www.atis.org/ndai/ATIS_NDAI_Final_Report_2006.pdf <war-story> I worked at a CLEC that purchased two SS7 links, one each from two Very Big Carriers. Both wound up going through the same fiber bundle in one particular market, on which both big guys leased bandwidth from A Minor Carrier. I've never seen a VP run as fast as when that backhoe hit us in Illinois; turns out they only *look* slow. </war-story> You never really know... David Hiers CCIE (R/S, V), CISSP ADP Dealer Services 2525 SW 1st Ave. Suite 300W Portland, OR 97201 o: 503-205-4467 f: 503-402-3277 -----Original Message----- From: Patrick W. Gilmore [mailto:patr...@ianai.net] Sent: Tuesday, July 28, 2009 8:26 AM To: NANOG list Subject: Re: XO - a Tier 1 or not? On Jul 28, 2009, at 11:18 AM, Pekka Savola wrote: > On Tue, 28 Jul 2009, Charles Mills wrote: >> Is XO Communications a Tier 1 ISP? > ... >> Any help here? Thanks as always. > > http://en.wikipedia.org/wiki/Tier_1_network Having written a good portion of that page, in the interest of full disclosure, I would like to point out some of the comments made while I was editing (and re-editing) the page. I do not _know_ XO has settlement agreements with Sprint & L3. Such contracts are covered by NDA, so (supposedly) only certain people inside Sprint, L3, and XO know whether XO is paying settlements. That said, does it matter? Settlement-Based may actually have a slight benefit over Settlement Free, as links which generate revenue may get upgraded faster than links which do not. Perhaps more importantly, does Transit Free matter? A network which has two diverse transit providers is orders of magnitude less likely to be affected by bifurcation events than transit free networks. Not to mention many non-transit free networks have better quality and service, IMHO, than some transit free networks. But hey, your money, your bits, so your decision. You want to buy from XO because they are Transit Free, or not buy from them because they are not Tier One, so be it. What's that line about competitors and encouragement... ? =) -- TTFN, patrick This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system.
