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Re: Cascading Failures Could Crash the Global Internet
by sgorman1＠gmu.edu 08 Feb '03

08 Feb '03

I believe the comments about heterogenous networks has to do with a measurement called assortivitiy that is used in statistical mechanics. A homogenous network is when nodes connect preferentially to nodes like them. In a heterogenous network they connect to nodes that are not like them. For networks like the Intneret and the electric grid it is measured by the number of connections a node has. The kicker, that the author's are alluding to, is that the more heterogenous a network is the more vulnerable it is to targeted attack. By taking out a highly connected node - lots of poorly connected nodes that use it as a hub are lost. The AS network had the highest heterogenous score of real-world tested networks, so lots of folks on that bandwagon. That said I don't think the tolerance parameter they set up in the paper makes much sense when applied to the Internet at the AS level. Basically it says once traffic exceeds a certain threshold the node will fail and cause cascades across the network. You guys are the experts but that does not sound overly realistic. ----- Original Message ----- From: Douglas Denault <doug(a)safeport.com> Date: Saturday, February 8, 2003 7:31 am Subject: Re: Cascading Failures Could Crash the Global Internet > > The model proposed makes several assumptions. My question is about: > > Many real-world networks are heterogeneous and as such are > expected to > undergo large-scale cascades if some vital nodes are attacked. > > on page 3. I do not get the basis for this assumption. So any help > for a 60's > educated math major would be appreciated. > > > On Thu, 6 Feb 2003 sgorman1(a)gmu.edu wrote: > > > > > The paper is avaibable on the Los Alamos site free of charge: > > > > http://xxx.lanl.gov/PS_cache/cond-mat/pdf/0301/0301086.pdf > > > > > > > > ----- Original Message ----- > > From: Sean Donelan <sean(a)donelan.com> > > Date: Thursday, February 6, 2003 12:43 pm > > Subject: Cascading Failures Could Crash the Global Internet > > > > > > > > > > > Sigh, there are differences between tightly coupled networks, > such as > > > the electric power grid and loosely couple networks like the > > Internet. > > > But there are also some similarities, such as electric grids > use DC > > > interconnections to limit how far AC disturbances propagate; the > > > Internet uses AS interconnections to limit IGP disturbances from > > > propagating. > > > > > > http://sci.newsfactor.com/perl/story/20686.html > > > > > > The actual article requires payment to read > > > http://ojps.aip.org/getabs/servlet/GetabsServlet? > > prog=normal&id=PLEEE8000066000006065102000001&idtype=cvips&gifs=Yes > > > > > > > > > > > > > _____ > Douglas Denault > doug(a)safeport.com > Voice: 301-469-8766 > Fax: 301-469-0601 > > >

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Re: Cascading Failures Could Crash the Global Internet
by sgorman1＠gmu.edu 08 Feb '03

08 Feb '03

The paper is avaibable on the Los Alamos site free of charge: http://xxx.lanl.gov/PS_cache/cond-mat/pdf/0301/0301086.pdf ----- Original Message ----- From: Sean Donelan <sean(a)donelan.com> Date: Thursday, February 6, 2003 12:43 pm Subject: Cascading Failures Could Crash the Global Internet > > > Sigh, there are differences between tightly coupled networks, such as > the electric power grid and loosely couple networks like the Internet. > But there are also some similarities, such as electric grids use DC > interconnections to limit how far AC disturbances propagate; the > Internet uses AS interconnections to limit IGP disturbances from > propagating. > > http://sci.newsfactor.com/perl/story/20686.html > > The actual article requires payment to read > http://ojps.aip.org/getabs/servlet/GetabsServlet? prog=normal&id=PLEEE8000066000006065102000001&idtype=cvips&gifs=Yes > > >

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Re: Odd DNS responses for www.neopets.com
by Crist J. Clark 07 Feb '03

07 Feb '03

David Russell wrote: > > Maybe it's just me, but isn't there something odd about a DNS query > > coming back with 78 entries for the same host? It sends back an UDP > > packet that gets truncated and the DNS resolver reverts to TCP to get > > the full list. [snip] > > > > It seems to cause problems with Windows clients and/or Windows DNS > > servers. Seems like overkill. > > > I feel your pain because I use a DNS module in my scripts that craps out > when it sees one of these truncated packets, but then the problem is with > the client and not DNS. It is too bad that the DNS packet size can't be > increased to 1500B. It can, RFC2671. -- Crist J. Clark | cjclark(a)alum.mit.edu | cjclark(a)jhu.edu http://people.freebsd.org/~cjc/ | cjc(a)freebsd.org

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OFF-TOPIC RE: Cisco 7507, erratic behaviour
by Lane Patterson 07 Feb '03

07 Feb '03

This subject is a bit off-topic for Nanog. You may have more success calling Cisco TAC and if you still need to, posting this kind of stuff to cisco-nsp: http://puck.nether.net/cisco-nsp/ Cheers, -Lane > -----Original Message----- > From: Drew Weaver [mailto:drew.weaver@thenap.com] > Sent: Friday, February 07, 2003 1:12 PM > To: 'nanog(a)merit.edu' > Subject: Cisco 7507, erratic behaviour > > > > Howdy, Im having a little difficulty with a 7507, when > I do sh run > it just returns a newline and doesn't show me any the > running-configuration. > My privelege level is 15, and this worked yesterday. I also > did wr term, > same thing.. New line.. Nothing.. My start-config hasn't been > modified, and > show start works great. Everything is working Ok in the > router, however I am > concerned for obvious reasons. ;-) > > Thanks, > -Drew >

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RADB news and NANOG helpdesk hours
by Larry J. Blunk 07 Feb '03

07 Feb '03

This is an update on recent changes to the Merit RADB Internet routing registry and announcement of helpdesk hours at the Phoenix NANOG meeting. In December of 2002, the RADB was officially rechristened the "Merit Routing Assets Database" and a redesigned website at www.radb.net was unveiled. In addition, there is now a web-based interface for RADB additions and updates. This interface may be reached at the following URL -- http://www.radb.net/cgi-bin/radb/irr-web.cgi. Merit has been actively involved with the RPSLng effort to update the RPSL standard to support IPv6 and Multicast routing policy. We have an initial implementation of the specification as documented in the following Internet draft: http://www.ietf.org/internet-drafts/draft-damas-rpslng-00.txt We expect to deploy this implementation in RADB registry shortly. In addition, we are working with Internet2 members to develop the I2 routing registry as an IPv6 routing registry and resource for the Internet2 community. The RADB team will once again hold a helpdesk at the NANOG meeting. Helpdesk hours are as follows: monday 10:15 break monday 3:00 break tuesday 10:35 break tuesday 12:00 lunch Regards, Larry J. Blunk Merit RADB

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Cascading Failures Could Crash the Global Internet
by Sean Donelan 07 Feb '03

07 Feb '03

Sigh, there are differences between tightly coupled networks, such as the electric power grid and loosely couple networks like the Internet. But there are also some similarities, such as electric grids use DC interconnections to limit how far AC disturbances propagate; the Internet uses AS interconnections to limit IGP disturbances from propagating. http://sci.newsfactor.com/perl/story/20686.html The actual article requires payment to read http://ojps.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PLEEE800006…

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EuroNOG
by Nicolas DEFFAYET 07 Feb '03

07 Feb '03

Hello, I forward this on behalf of my colleague. (When my colleague send a message to nanog(a)merit.edu, his message is not published on the list. He don't get errors and he subscribed to nanog and nanog-post.) -----Forwarded Message----- From: Mike CHENEY <mike.cheney(a)ndsoftware.net> To: nanog(a)merit.edu Subject: EuroNOG (European Network Operators Group) Date: 04 Feb 2003 00:18:41 +0100 Hi folks, For european people, there is now a group called EuroNOG with about the same goals as Nanog. For more information: http://www.euronog.org/ For subscribe to EuroNOG mailing-list, send a mail to euronog-subscribe(a)ml.euronog.org. Regards, Mike Note: message resent because not received by the list. -----Forwarded Message----- Best Regards, -- Nicolas DEFFAYET, NDSoftware

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AADS Website
by Andre Chapuis 07 Feb '03

07 Feb '03

Hi there, www.aads.net lost its Internet connectivity some weeks ago, and is unaccessible. As an AADS customer, i asked for a peering with AS10764 to have access to the website, what seems me to be part of the AADS service, but they did not accept. Anybody else experiencing problems with AADS ? Cheers, André --------------------- Andre Chapuis IP+ Engineering Swisscom Ltd Genfergasse 14 3050 Bern +41 31 893 89 61 chapuis(a)ip-plus.net CCIE #6023 ----------------------

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The Cidr Report
by cidr-report＠potaroo.net 07 Feb '03

07 Feb '03

This report has been generated at Fri Feb 7 21:46:10 2003 AEST. The report analyses the BGP Routing Table of an AS4637 (Reach) router and generates a report on aggregation potential within the table. Check http://www.cidr-report.org/as4637 for a current version of this report. Recent Table History Date Prefixes CIDR Agg 31-01-03 118463 85095 01-02-03 118556 85054 02-02-03 118567 85128 03-02-03 118587 85148 04-02-03 118588 85028 05-02-03 118502 85128 06-02-03 118561 85108 07-02-03 118526 85124 AS Summary 14519 Number of ASes in routing system 5722 Number of ASes announcing only one prefix 1584 Largest number of prefixes announced by an AS AS701 : ALTERNET-AS UUNET Technologies, Inc. 72916992 Largest address span announced by an AS (/32s) AS568 : SUMNET-AS DISO-UNRRA Aggregation Summary The algorithm used in this report proposes aggregation only when there is a precise match using the AS path, so as to preserve traffic transit policies. Aggregation is also proposed across non-advertised address space ('holes'). --- 07Feb03 --- ASnum NetsNow NetsAggr NetGain % Gain Description Table 118612 85169 33443 28.2% All ASes AS3908 1058 579 479 45.3% SUPERNETASBLK SuperNet, Inc. AS18566 457 7 450 98.5% COVAD Covad Communications AS701 1584 1171 413 26.1% ALTERNET-AS UUNET Technologies, Inc. AS7018 1433 1041 392 27.4% ATT-INTERNET4 AT&T WorldNet Services AS4323 528 170 358 67.8% TW-COMM Time Warner Communications, Inc. AS6197 472 154 318 67.4% BATI-ATL BellSouth Network Solutions, Inc AS7843 568 253 315 55.5% ADELPHIA-AS Adelphia Corp. AS1221 1133 829 304 26.8% ASN-TELSTRA Telstra Pty Ltd AS1239 964 678 286 29.7% SPRINTLINK Sprint AS7046 563 280 283 50.3% UUNET-CUSTOMER UUNET Technologies, Inc. AS6347 367 85 282 76.8% DIAMOND SAVVIS Communications Corporation AS22927 295 14 281 95.3% AR-TEAR2-LACNIC TELEFONICA DE ARGENTINA AS4355 396 120 276 69.7% ERMS-EARTHLNK EARTHLINK, INC AS4151 345 71 274 79.4% USDA-1 USDA AS705 437 189 248 56.8% ASN-ALTERNET UUNET Technologies, Inc. AS4814 261 15 246 94.3% CHINANET-BEIJING-AP China Telecom (Group) AS852 680 444 236 34.7% ASN852 Telus Advanced Communications AS6198 432 201 231 53.5% BATI-MIA BellSouth Network Solutions, Inc AS1 665 435 230 34.6% GNTY-1 Genuity AS22291 238 31 207 87.0% CHARTER-LA Charter Communications AS17676 222 26 196 88.3% GIGAINFRA XTAGE CORPORATION AS209 532 341 191 35.9% ASN-QWEST Qwest AS690 498 308 190 38.2% MERIT-AS-27 Merit Network Inc. AS4134 301 117 184 61.1% ERX-CHINALINK Data Communications Bureau AS2386 437 263 174 39.8% INS-AS AT&T Data Communications Services AS2048 259 87 172 66.4% LANET-1 State of Louisiana AS17557 336 186 150 44.6% PKTELECOM-AS-AP Pakistan Telecom AS6140 284 135 149 52.5% IMPSAT-USA ImpSat AS6327 186 40 146 78.5% SHAWFIBER Shaw Fiberlink Limited AS11492 307 164 143 46.6% CABLEONE CABLE ONE Total 16238 8434 7804 48.1% Top 30 total Please see http://www.cidr-report.org for the full report ------------------------------------ Copies of this report are mailed to: nanog(a)merit.edu eof-list(a)ripe.net apops(a)lists.apnic.net routing-wg(a)ripe.net afnog(a)afnog.org

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Outage: 400,000 subscribers in Puerto Rico
by Sean Donelan 07 Feb '03

07 Feb '03

The Associated Press is reporting that 400,000 Telefonica de Puerto Rico subscribers lost long-distance telephone service due to possible sabotage.

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