North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: PAIX
SS> Date: Thu, 14 Nov 2002 13:32:55 -0600 SS> From: Stephen Sprunk SS> Incorrect. Cheap longhaul favors a few centralized SS> exchanges. If there is no economic value in keeping traffic SS> local, it is in carriers' interests to minimize the number of SS> peering points. True. However, cheap longhaul / expensive local means providers _will_ try to reduce loop costs, favoring "carrier hotels". SS> Most vendor-neutral colos have cheap zero-mile loops. Correct. In my original post... are we discussing #1 or #2? It seems as if #2. Where are we drawing the line between "carrier hotel" and "exchange"? I believe Paul was being perhaps more nebulous than today's definition of "exchange" when he referenced 1500 sq-ft in-bottom-of-bank-building facilities. SS> What is the cost of running N loops across town, vs. the cost SS> of pushing that traffic to a remote peering location and SS> back? Be sure to include equipment, maintenance, and SS> administrative costs, not just circuits. "It depends." SS> None of these applications require local exchanges. There is SS> a slight increase in end-to-end latency when you must use a SS> remote exchange, but very few applications care about SS> absolute latency -- they only care about bandwidth and SS> jitter. With bounded latency and "acceptable" typical throughput, one seeks to minimize jitter and cost. Jitter is caused by variable queue time, which is due to buffering, which is a side-effect of statmuxed traffic w/o strict { realtime delivery constraints | QoS | TDM-ish architecture }... yes. And N^2 makes full-mesh irresponsible when attempting to maximize bandwidth... yes. (I think buying full transit from 10 providers is well beyond the point of diminishing return; no offense to INAP.) Again... if loop is expensive, and providers are concentrated in "carrier hotels" with reasonably-priced xconns... when does it become an "exchange"? Note that some exchanges do not provide a switch fabric, but rather run xconns. Sure, one must factor in all the costs. The breakeven point varies, if it exists at all. SS> Distributed content assumes the source is topologically close SS> to the sink. The most cost-efficient way to do this is put SS> sources at high fan-out areas, as this gets them the lowest SS> _average_ distance to their sinks. This doesn't necessarily SS> mean that putting a CNN mirror in 100,000 local exchanges is SS> going to reduce CNN's costs. It depends. Akamai certainly is overkill for smaller sites, and perhaps not cost-effective for others. However, high fan-out can be a _bad_ thing too: Assuming one has substantial traffic flow to various regions, why source everything from NYC? Why not replicate in London, AMS, SJO, IAD, CHI, DFW, LAX, SEA, KSCY? >From a source's point, distribution makes sense when cost of geographically-diverse server presence (incremental admin/hw, content distribution) is less than the cost of serving everything from a centralized point. Once that happens... if a substantial portion of Internet traffic were sourced from one local point, sinks would gravitate toward said point. Of course, I may well be stuck in distance-sensitive mode. If local loop is the primary expense... we're back to what you said about "few, centralized exchanges" and "many carrier hotels"? So, where's the dividing line? Eddy -- Brotsman & Dreger, Inc. - EverQuick Internet Division Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 (785) 865-5885 Lawrence and [inter]national Phone: +1 (316) 794-8922 Wichita ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Date: Mon, 21 May 2001 11:23:58 +0000 (GMT) From: A Trap <[email protected]> To: [email protected] Subject: Please ignore this portion of my mail signature. These last few lines are a trap for address-harvesting spambots. Do NOT send mail to <[email protected]>, or you are likely to be blocked.
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