July 1996 - Test - lists.nanog.org

Just how big a load are UDP broadcasts?
by Dick St.Peters 06 Aug '96

06 Aug '96

I run a small network of small sites, including a couple in the Adirondacks with 56k feeds. When a user of one of these sites uses one of the UDP audio or video services it drives the 56k to 100% saturation (load 255/255) and makes the site unusable for everyone else. Recently I "solved" this problem by blocking this traffic at the entry port for my T1 feed. To my surprise, both the average and peak traffic on the T1 dropped by a factor of 3, although less than 2% of my users complained. Traffic on my T1 wasn't the issue, but this has me wondering: how much of the Internet congestion my users do complain about is due to UDP audio/video services? In my very limited view of the world, UDP is a very poor network citizen among protocols. Am I wrong in that view? -- Dick St.Peters, Gatekeeper, Pearly Gateway, Ballston Spa, NY stpeters(a)NetHeaven.com Owner, NetHeaven 518-885-1295/800-910-6671 Internet for Albany/Saratoga, Glens Falls, North Creek, & Lake Placid First Internet service based in the 518 area code

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totd
by Kelly J. Cooper 04 Aug '96

04 Aug '96

Traceroute of the day: traceroute to styx.ios.com (198.4.75.44), 30 hops max, 40 byte packets 1 cambridge1-cr1.bbnplanet.net (192.52.71.11) 3 ms 7 ms 8 ms 2 cambridge2-cr2.bbnplanet.net (192.233.149.202) 3 ms 3 ms 2 ms 3 alternet.bbnplanet.net (192.233.33.8) 4 ms 3 ms 3 ms 4 Hssi4-0.Boston3.MA.Alter.Net (137.39.100.97) 4 ms 3 ms 3 ms 5 Fddi0-0.Boston6.MA.Alter.Net (137.39.99.10) 5 ms 4 ms 4 ms 6 Hssi2-0.CR1.BOS1.Alter.Net (137.39.101.166) 130 ms 196 ms 11 ms 7 103.Hssi4-0.CR2.SCL1.Alter.Net (137.39.58.133) 93 ms 93 ms 94 ms 8 137.39.19.36 (137.39.19.36) 97 ms 93 ms 93 ms 9 137.39.63.35 (137.39.63.35) 99 ms 138 ms 96 ms 10 arpanet^255.255.2 (10.255.255.2) 178 ms 228 ms 234 ms 11 eth-0.gw-7.hck.idt.net (169.132.34.246) 297 ms 204 ms 249 ms 12 206.20.143.34 (206.20.143.34) 273 ms 230 ms 263 ms 13 styx.ios.com (198.4.75.44) 239 ms 288 ms 321 ms -- Kelly J. Cooper Network Analyst BBN Planet Corporation phone 800-632-7638 150 Cambridge Park Drive fax 617-873-6351 Cambridge, MA 02140 http://www.bbnplanet.com

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Re: I-D (Re: Out of date contact information )
by sob＠academ.com 30 Jul '96

30 Jul '96

I would suggest adding "hostmaster" for DNS issues (and suggesting that this be the address listed as the contact in DNS SOA records). -- Stan | Academ Consulting Services |internet: sob(a)academ.com Olan | For more info on academ, see this |uucp: {mcsun|amdahl}!academ!sob Barber | URL- http://www.academ.com/academ |Opinions expressed are only mine.

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Re: ATM Wide-Area Networks
by salo＠msc.edu 30 Jul '96

30 Jul '96

>From: Sean Doran <smd(a)icp.net> >To: pferguso(a)cisco.com, salo(a)msc.edu >Subject: Re: sell shell accounts? >Cc: nanog(a)merit.edu >Date: Wed, 24 Jul 1996 01:43:30 +0100 > >| o Given that each link is rather expensive, it behooves the >| NSP to try to avoid needlessly moving a packet back and >| forth across a DS-3 local loop just because my ATM >| provider can't provide me with any more PVCs. >| (Which was my major point, by the way.) > >Interestingly enough, the NSPs I observe moving large amounts >of traffic around are set up in such a way that their routers >are generally colocated with carrier transmission gear, and >so there *is* no local loop to speak of, as an added cost to >an outside supplier. > [...] Hopefully, my thinking is clearer than my writing... What I originally called "local loop B," now relabeled "This Thing Here," is probably comprised of: o a port on the ATM switch/service o a connection between the router and the switch, (usually a wide-area link, given that most wide-area ATM services backhaul traffic to a few ATM switches) o a port on the router A short-cut VC would avoid needlessly passing packets back and forth across "This Thing Here." That would seem to be a good thing in most circumstances, inasmuch as some or all of the components of "This Thing Here" cost something and may potentially become a bottleneck. -tjs | ________ _______________________ ________ | | Router | loop A | | loop C | Router | | | A |=========| Wide-Area ATM Service |========| C | | |________| |_______________________| |________| | | | | <=== This Thing Here | | | ________ | | Router | | | B | | |________|

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Re: Ping triangulation
by Peter Lothberg 29 Jul '96

29 Jul '96

> They use the ping times to figure out which server would be closest. > All the servers are not located in the same place. The idea is that > european users may receive better service from a european server. > > Roy > > > The network topology and geography does not match very well, I would guess that the network center of Europe is likely to be somwhere on the US Eastcoast. Only Stockholm have multiple international E3 links.... --Peter

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Re: ATM Wide-Area Networks
by salo＠msc.edu 29 Jul '96

29 Jul '96

> > I am not quite sure how an ATM switch becomes a "packet shredder," or > > even what a "packet shredder" is... > > An ATM switch shreds a 1500 byte IP packet into 29 ATM cells of 53 bytes > each. At the risk of being excessively pedantic, the host ATM interface, not the switch, segments the SDU into cells. My point was that the term "packet shredder" doesn't seem to have any very precise meaning beyond perhaps the writer's desire to use a catchy phrase to indicate an attitude towards ATM. Some people use it to describe the segmentation function of ATM interfaces, other use it to describe switches which don't do packet discard. > If an ATM has a 5% loss, i.e. 1 in every 20 cells is lost, then 0% > of the IP traffic will get through. ... Most anything with 5% loss is broken. -tjs

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Re: Why aren't ISPs providing stratum 1 NTP service?
by dgaudet＠hotwired.com 29 Jul '96

29 Jul '96

In article <hot.mailing-lists.nanog-Pine.BSI.3.93.960719091042.14736C-100000(a)sidhe.memra.com>, Michael Dillon <michael(a)memra.com> wrote: >And heavily used WWW servers are another thing that could benefit from >aligning themselves with the topology. The protocols don't support this cleanly. So far nothing I've seen would allow a single URL to be used to access the "nearest" server. Until something like that exists (i.e. the end users don't need to know a thing about network topology) it seems pointless to align WWW servers with the topology. Your suggested use of redirects just complicates things -- consider how the URLs would end up looking in a search engine. Dean

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Re: ATM Wide-Area Networks (was: sell shell accounts?)
by Vincent J. Bono 27 Jul '96

27 Jul '96

<snip> > ATM can be used in two main modes: as a funny form of TDM > or as a means of overcommitting resources. > > The former is in use now in the land of InternetMCI, > ESNET, NSI and others, for better or for worse, and has > been for some time. As Tim and others have pointed out, > it works, given some tweaking here and there with things > like EPD. > > The latter has been observed in use as an offering by MFS, > and it had obvious problems. It has also been observed > from time to time at the ATM-using NAPs, and also had > obvious problems. These problems were arguably not > directly the fault of ATM, but of arguably broken > interface and adaptation devices like ADSUs, ethernet > framers and FRADs. I'd wonder if a large part of the problems are not avoidable, but that since most persons do not as yet have a "feel" for ATM, its harder to see and diagnose building problems, or predict failure points. ATM acting like TDM *still* isn't TDM. "Load" testing is fine and well (sorry DISA folks) but it's the field use that matures technology and turns proposed process into good technique. We've watched the ATM simulations (and even helped with the code for a few) but nothing came close to predicting what happened in real life when clients implemented it, especially in the multimedia (IP/TV/VOICE) applications. -v

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Re: Why aren't people changing their subject lines when threads drift?
by Justin W. Newton 26 Jul '96

26 Jul '96

At 11:42 PM 7/25/96 -0700, you wrote: >> Isn't IBM doing some sort of fancy load redistribution for the WWW >> servers its running for the 1996 Summer Olympics? I seem to recall they >> were determining the "closest" server via a technique called "ping >> triangulation", whatever that is. > >If so, that's pretty silly and is probably not leading to performance >that's very different from either purely random or strict round robin. > >Ping times only correlate to available bandwidth when congestion is bad. >Otherwise these two factors are militantly unrelated to each other. Well, I suppose all they have to do is buil a global OSPF network encompassing the entire internet and they'd be set. Justin "Yes I'm kidding" Newton Justin Newton Internet Architect Erol's Internet Services

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route servers
by Shifter 25 Jul '96

25 Jul '96

Are there any other routers that allow incoming telnet sessions without a password besides route-server.cerf.net? -John -- shifter(a)portal.stwing.upenn.edu -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6.2 mQCNAzF+qeMAAAEEALdaUpOTi8EtNjZMA9URTXGmQq1NPdyRSx2JXhQ7Q8Yz9qxU q3tqRtlydRqp37VPmygibGB8eS7RptqolTlYvrVMHXSDcZjKpgpZA9d+3rCKUaLM F9Hvltl2EafIEspVoNUYahpdXof4oMjs2sKGzJO8aDwyM34pRaicZR8SZJz9AAUR tClTaGlmdGVyIDxzaGlmdGVyQHBvcnRhbC5zdHdpbmcudXBlbm4uZWR1Pg== =Eucp -----END PGP PUBLIC KEY BLOCK-----

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