October 2000 - Test - lists.nanog.org

Re: decreased caching efficiency?
by Simon Leinen 20 Oct '00

20 Oct '00

>>>>> "ld" == Lincoln Dale <ltd(a)interlink.com.au> writes: > caches exist for multiple reasons -- > [1] to make things faster > [2] to save bandwidth > [3] to achieve more "goodput" in network transactions. > [4] to operate at layers-8 and 9 (filtering) [...] > in many cases, people significantly underestimate the effect of #3 - > and it isn't easily measured. it is the effect of a "good" tcp stack > cutting down end-to-end tcp retransmissions when the "last mile" hop > is congested. Not just when it is congested... whenever the proxy (I'm deliberately not talking about "caches"---even a cacheless proxy would have this effect) has RTTs to the origin server and the browser which are both lower than the "e2e" server<->browser RTT, then the TCP control loop will react faster to changing network conditions. This includes faster "ramping up" to available bandwidth, and higher achievable throughput if the same window size is used. Note also that proxies can affect goodput adversely, for example when both the origin server and browser host support larger TCP window sizes than the proxy. This artificially limits throughput when there's little or no congestion over paths with high RTT. I think this is quite common because it is easier for browser hosts than for proxies to support larger TCP windows---proxies have to support high numbers of concurrent TCP connections, and using large windows may incur very significant kernel memory overhead unless OS developers do clever memory-allocation things. -- Simon.

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RE: the new 6509 OSR
by baburn - Bart Burns 20 Oct '00

20 Oct '00

My understanding is that the ESR will serve as high-density aggregation for traditional WAN circuits. 56Kb to DS-3. The OSR will serve as high-density aggregation for DS-3 ot OC-192. Bart Burns Network Engineer Acxiom Corporation (501) 342-4167 email bart.burns(a)acxiom.com -----Original Message----- From: Neil J. McRae [mailto:neil@COLT.NET] Sent: Thursday, October 19, 2000 9:35 AM To: baburn(a)acxiom.com Cc: nanog(a)merit.edu Subject: Re: the new 6509 OSR I thought that the ESR was the new 75xx class box? Regards, Neil. [Charset iso-8859-1 unsupported, filtering to ASCII...] > We are about to purchase several of these OSR's. Here is what we know about > the OSR. If you look at the roadmap for the OSR, Cisco is positioning this > platform to be the next 75xx class device only it will be for high-speed > connectivity at DS-3 or greater. It will scale all the way to OC-192 or 10 > Gig Ethernet. The main reason we are looking at the OSR vs a plain jane > 6509 is because the OSR can serve as a high-speed ingress point to the MPLS > backbone that we are about to deploy. The OSR interfaces have deeper > interface buffers than the plain 6509. > > Bart Burns > Network Engineer > Acxiom Corporation > (501) 342-4167 > email bart.burns(a)acxiom.com > <<Bart Burns (E-mail).vcf>> [Attachment, skipping...]

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Re: decreased caching efficiency?
by Scott Gifford 19 Oct '00

19 Oct '00

All of these problems are solvable, using common and well-known techniques: Daniel Senie <dts(a)senie.com> writes: > It might be worth thinking about the problem from the other end. From a > web site owner's perspective, caching is a major annoyance. Here are the > arguments you may encounter from a web site owner or web developer: > > 1. It interferes with content in many cases (web site visitors may see > cached pages instead of current content). I know cache products claim > this doesn't happen, but it has, and often. Most (all?) reasonable caching products will honor whatever expiration information you put in the page, such as the Cache-Control header and Expires header. Where I've made careful use of these, I've never had problems with stale content, even from browser caches. > 2. The website owner loses information on how many visitors are coming > to the site. A common technique to just count Web page hits is to <img src> a small image on the page, and then use that to count page visits, or to have the page itself not be cacheable, but the images (which are most of the load time) cachable. Having the page itself be dynamic and uncachable, while the images can always be cached, can be a big win all around; dynamic images are fairly rare (except from MRTG. :) ) > 3. The website owner loses the demographics on where visitors are coming > from, and especially the number of unique visitors. (It's not helpful to > know that one cache engine visited, if that cache engine equated to > 10,000 visits in an hour). You can use the X-Forwarded-For header that many caches provide to gather this same information. In the future, you may be able to use the protocol described in RFC 2227 to get more detailed information. > 4. Banner advertising may or may not display properly when caching is > involved, thereby costing the website money. I've never experienced this; I've been viewing the Web through a cache or a hierarchy of caches for 2 years now, and I've never noticed anything weird with banner ads. At least nothing an "Expires: 0" wouldn't solve. > 5. There's NOTHING in it for the website owner, other than the > possibility that SOME pages might display faster for SOME users. > > If folks running networks really think website designers and owners > should care about caching, then there needs to be some sort of benefit > (perhaps paid in dollars) to those affected. Otherwise, there's little > reason for them to care. I don't understand this; having Web pages which are effectively cached around the world reduces the load on your servers significantly (especially as more and more ISPs start to cache), and saves you significant bandwidth. This lets you buy fewer servers for your farm, and buy less upstream bandwidth. Right now, having a site which is cache friendly can save you money in a big way, at the same time savin ISPs money, making your page display how you want it (since the ISPs are already deploying caching, whether your pages are friendly to it or not), and having the page load faster for quite a few users. How is that not a benefit? How is that not paid in dollars? In the future, if Webserver operators would take effective cache performance while maintaining correct display into account when configuring their servers, and make sure that page designers do the same, that would allow caches to become more ubiquitous, and push people to set up large-scale cache hierarchies. It could get to the point where all of the non-dynamic content from an infinitely large Website could be served by an old desktop computer over a 28.8 modem, since it would just have to send its content once to the UUNet cache, once to the MCI/Worldcom cache, once to the Sprint cache, etc. Of course, that's still a ways off. :) Just my 2 cents, ------ScottG.

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Re: decreased caching efficiency?
by Adrian Chadd 19 Oct '00

19 Oct '00

On Thu, Oct 19, 2000, Marshall Eubanks wrote: > Not every body likes spy-ware : > > http://www.buzzwaves.com/article.pl?sid=00/10/18/1325217&mode=thread * I hardly consider a gif on a website spyware, considering that the rest of the webpage contains gifs that would return just the same information and * Thats with email, not web. With web, you request a page which contains images. With email, you request a piece of email. If the email manages to escape its little email sandbox, thats the fault of the people who wrote the client. "spyware" is the wrong term here. "improving client access times" and "decreasing bandwidth requirements" are the right terms here.. Adrian -- Adrian Chadd "It was then that I knew that I wouldn't <adrian(a)creative.net.au> die, as a doctor wouldn't fart in front of a dying boy." -- Angela's Ashes

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RE: the new 6509 OSR
by baburn - Bart Burns 19 Oct '00

19 Oct '00

We are about to purchase several of these OSR's. Here is what we know about the OSR. If you look at the roadmap for the OSR, Cisco is positioning this platform to be the next 75xx class device only it will be for high-speed connectivity at DS-3 or greater. It will scale all the way to OC-192 or 10 Gig Ethernet. The main reason we are looking at the OSR vs a plain jane 6509 is because the OSR can serve as a high-speed ingress point to the MPLS backbone that we are about to deploy. The OSR interfaces have deeper interface buffers than the plain 6509. Bart Burns Network Engineer Acxiom Corporation (501) 342-4167 email bart.burns(a)acxiom.com <<Bart Burns (E-mail).vcf>>

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RE: the new 6509 OSR
by Roeland M.J. Meyer 19 Oct '00

19 Oct '00

I've used them and they are my fav LAN switch, when I can justify the bandwidth. I've installed two in the past 10 months. > rick we will be demoing some of these very shortly - I will > give you any > feedback we collect... > > On Wed, 18 Oct 2000, rick wrote: > > > > > Hi all, > > > > In the UK Cisco are going to release the OSR's in December, > has any one any > > where else used these switches..... I only ask because we > in the process of > > buying a few 6509 and would prefer the higher switching > capacity but I would > > like a few words of wisdom..... > > > > After all Cisco say they are brill, but !!!! > > > > Any advise is always welcome > > > > Thanks > > Richard Smith > > Firstnet > > Leeds > > email: rsmith(a)firstnet.co.uk > > > ************************************************************** > ************** > > ****** > > > > This email and any files transmitted with it are > confidential and intended > > solely for the use of the individual or entity to whom they > are addressed. > > The views expressed in the email and files transmitted with > it are those of > > the individual, not the company. If you have received this > email in error > > please notify rsmith(a)firstnet.co.uk > > > > ******************************************** > > ************************************** > > > > > > -- > In a brood of blind back biting vipers... > ...the one-eyed snake is king! > Rich Sena -.~~~ssssSSSSiSSSSssss~~~.- ras(a)thick.net > > >

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the new 6509 OSR
by rick 18 Oct '00

18 Oct '00

Hi all, In the UK Cisco are going to release the OSR's in December, has any one any where else used these switches..... I only ask because we in the process of buying a few 6509 and would prefer the higher switching capacity but I would like a few words of wisdom..... After all Cisco say they are brill, but !!!! Any advise is always welcome Thanks Richard Smith Firstnet Leeds email: rsmith(a)firstnet.co.uk **************************************************************************** ****** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. The views expressed in the email and files transmitted with it are those of the individual, not the company. If you have received this email in error please notify rsmith(a)firstnet.co.uk ******************************************** **************************************

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MPLS implementation
by Irwin Lazar 17 Oct '00

17 Oct '00

Hi folks, If anyone out there is currently involved in integrating MPLS into service provider networks and would like to present a case study at next year's MPLScon event, please drop me a line. Thanks, Irwin ilazar(a)tbg.com

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Miami
by pete fortman 16 Oct '00

16 Oct '00

I am doing some research on connecting in Miami. Does anyone have an opinion on how well L3 Xroads is doing there? Thanks in advance, Pete Fortman _______________________________________________________ Say Bye to Slow Internet! http://www.home.com/xinbox/signup.html

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Going till 3 on Tuesday
by Susan R. Harris 16 Oct '00

16 Oct '00

Hi everyone - just wanted to let you know that with the addition of a new talk on Tuesday, NANOG20 will now end a bit after 3:00 p.m. on the 24th.

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