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RE: Why choose 120 volts? When DC will do
by John Lee 26 May '09

26 May '09

What is all this talk about AC. Real data centers use DC. John (ISDN) Lee ________________________________________ From: Seth Mattinen [sethm(a)rollernet.us] Sent: Tuesday, May 26, 2009 3:39 PM To: nanog(a)nanog.org Subject: Why choose 120 volts? I have a pure curiosity question for the NANOG crowd here. If you run your facility/datacenter/cage/rack on 120 volts, why? I've been running my facility at 208 for years because I can get away with lower amperage circuits. I'm curious about the reasons for using high-amp 120 volt circuits to drive racks of equipment instead of low-amp 208 or 240 volt circuits. ~Seth

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RE: Why choose 120 volts?
by Gregory Hicks 26 May '09

26 May '09

> Subject: RE: Why choose 120 volts? > Date: Tue, 26 May 2009 15:23:46 -0500 > From: "Kurt Anderson" <kurt(a)honeycomb.net> > To: <nanog(a)nanog.org> > > Why stop there? Grab a 20,000 volt feeder and create a Tesla > datacenter. Think of all the copper you will save... Boy! This thread went south in a hurry! I about died laughing. > > -----Original Message----- > From: telmnstr(a)757.org [mailto:telmnstr@757.org] > Sent: Tuesday, May 26, 2009 3:16 PM > Cc: nanog(a)nanog.org > Subject: RE: Why choose 120 volts? > > >> Oh, yeah! Nothing sounds like more fun than working in a room full of > >> 480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to > >> have a functioning heart.) > > Nobody said delta. > > If you just run 7200vac into your 1u chinese made peecee servers, then > you > can eliminate the space use of the step-down transformer in the > mechanical > room. > > > --------------------------------------------------------------------- Gregory Hicks | Principal Systems Engineer | Direct: 408.569.7928 People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf -- George Orwell The price of freedom is eternal vigilance. -- Thomas Jefferson "The best we can hope for concerning the people at large is that they be properly armed." --Alexander Hamilton

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Re: MX Record Theories
by gb10hkzo-nanog＠yahoo.co.uk 26 May '09

26 May '09

Hi, > I thought i'd give you a quick response (and welcome to NANOG) :). Thanks. I can't believe that I've already received three very interesting responses in just over an hour ! I've been quietly lurking on NANOG for a while, just plucked up the courage to post ..... and might now even find a bit more courage to attempt to contribute to some threads ! Glad to see the community spirit still exists ! Keep the replies coming if there are any still on their way ..... :) Tim P.S. Valdis Kletnieks ..... I've got the feeling that this .... > That 507 is critically important if it's true, might potentially explain a few intermittent unexplicable issues we've been seeing at some sites .... time for some research me thinks.... :)

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PLNOG3 - 10-11.09.2009 - Call for Papers!
by Lukasz Bromirski 26 May '09

26 May '09

Hello, Polish Network Operators Group (PLNOG)[1] will meet for the third time ever on 10th and 11th of September 2009 in Cracow, Poland. We would like to invite You all to submit your presentation proposal. The plan for PLNOG 3rd is to have three tracks: * Architectures and technologies - sessions covering networking solutions, future of standards and the standarization process for current technologies; * Real-life deployments and best practices - sessions covering first-hand experience with deployment of specific solutions, products and solutions * Content provider architecture and scalability - dedicated for people interested in building backends for all kinds of networking sites like portals, community sites and etc. Additionally, we would like to invite You to suggest subjects for the open discussion sessions that will take place before the main event and after the keynotes. Last subjects revolved around IPv6 deployment and lawful intercept issues from the government and practical point of view. The submissions will be discussed by the PLNOG board[2], so the dead line for them is 25th of June, 2009. The full agenda with all sessions will be published no later than to 10th of July, 2009. CfP proposals should be sent to following e-mail: andrzej.targosz {%} proidea.org.pl with the prefix 'PLNOG3' in subject. We would also like to invite all vendors to participate in presentations - however, bear in mind please no vendor-oriented sessions will be permitted, which means no sales, no marketing, only pure technical stuff. The pointers to some specific design issues, products or solutions are allowed if they follow approved presentation flow and are relevant to subject covered. Last but not least - if You want to sponsor PLNOG we'd be more than happy to discuss this with You. [1]. http://www.plnog.pl [2]. http://plnog.pl/komiter-i-rada-nog/lang-pref/en/ -- "Don't expect me to cry for all the | Łukasz Bromirski reasons you had to die" -- Kurt Cobain | http://lukasz.bromirski.net

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[NANOG-announce] NANOG46 reminders
by Betty Burke 26 May '09

26 May '09

Hi Folks: One Last set of meeting reminders!! If you have not yet made your hotel reservations, you might want to consider doing so as the NANOG hotel room rate ends on Friday, May 29. Make sure to complete your NANOG registration soon, you do not want to miss out on an excellent program and opportunity to catch up in person with members of the NANOG community. On Monday, June 8 the registration late fee goes into effect. Lastly, do not forget to get those lighting talk ideas submitted! Look forward to seeing everyone in sunny Philly. Sincerely, Merit, NANOG Support Team _______________________________________________ NANOG-announce mailing list NANOG-announce(a)nanog.org http://mailman.nanog.org/mailman/listinfo/nanog-announce

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Multi-homed clients and BGP timers
by Steve Bertrand 26 May '09

26 May '09

Hi all, I've got numerous single-site 100Mb fibre clients who have backup SDSL links to my PoP. The two services terminate on separate distribution/access routers. The CPE that peers to my fibre router sets a community, and my end sets the pref to 150 based on it. The CPE also sets a higher pref for prefixes from the fibre router. The SDSL router to CPE leaves the default preference in place. Both of my PE gear sends default-originate to the CPE. There is (generally) no traffic that should ever be on the SDSL link while the fibre is up. Both of the PE routers then advertise the learnt client route up into the core: *>i208.70.107.128/28 172.16.104.22 0 150 0 64762 i * i 172.16.104.23 0 100 0 64762 i My problem is the noticeable delay for switchover when the fibre happens to go down (God forbid). I would like to know if BGP timer adjustment is the way to adjust this, or if there is a better/different way. It's fair to say that the fibre doesn't 'flap'. Based on operational experience, if there is a problem with the fibre network, it's down for the count. While I'm at it, I've got another couple of questions: - whatever technique you might recommend to reduce the convergence throughout the network, can the same principles be applied to iBGP as well? - if I need to down core2, what is the quickest and easiest way to ensure that all gear connected to the cores will *quickly* switch to preferring core1? Steve

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Global Crossing Contact
by Ken Gilmour 23 May '09

23 May '09

Hi There, I have been trying to get in touch with someone at AS3549 for about an hour but I can't seem to get through using normal methods (e.g. calling numbers on the site, email to noc(a)globalcrossing.com doesn't work, etc). Can anyone who manages this AS please contact me off-list? Thanks very much! Regards, Ken

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AH or ESP
by Glen Kent 22 May '09

22 May '09

Hi, It is well known in the community that AH is NAT unfriendly while ESP cannot be filtered, and most firewalls would not let such packets pass. I am NOT interested in encrypting the data, but i do want origination authentication (Integrity Protection). Do folks in such cases use AH or ESP-NULL, given that both have some issues? Thanks, Glen

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Pseudowire Problem
by Shivlu Jain 22 May '09

22 May '09

I have seen a weird behaviour in case of pseudo wire termination, it keeps on polling the destination ip even if the interface mapped to pseudo wire is down. Is it the normal behaviour? -- Thanks & Regards shivlu jain http://shivlu.blogspot.com/

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Global pricing disparity -> Somali piracy
by Martin Hannigan 22 May '09

22 May '09

FYI, I thought this was interesting reading for the workaholics among us as we head into the holiday weekend in the United States. I'd also like to follow it with an (hopefully) interesting question. http://www.circleid.com/posts/20090520_bandwidth_buyers_price_differences_g… The costs of wholesale bandwidth are significantly disparate by region, duh, but this article demonstrates how disparate. I was also recently discussing why some of these costs are disparate with a colleague in the African region and he had an interesting question that I thought would be operational enough to ask here. Are any African or Middle East costs being influenced by the Somali piracy problem? Is the deployment of Eassy being impacted by the piracy issue? The cable ships are sitting ducks for pirate attacks during lay and repair operations. There's one cable lay operation being guarded by the French Navy, likely an Alcatel operation. I'm interested to hear from anyone with direct knowledge (offline, I'll summarize back if it's worth it, maybe even a lightning talk for Philly?) on the impact. I suspect that it's possible that it could add cost to maintenance agreements with any security caveats, but since most cable operations taking place now were negotiated before the problem heightened, perhaps not. I'd like to know if you know. Best, Martin Hannigan -- Martin Hannigan martin(a)theicelandguy.com p: +16178216079 Power, Network, and Costs Consulting for Iceland Datacenters and Occupants

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