December 2008 - Test - lists.nanog.org

Network topology
by Colin Alston 15 Nov '13

15 Nov '13

Hi all I'm considering trying to come up with some means to automatically detect a networks topology and draw pretty pictures. This is somewhat boring though if a network isn't well arranged with VLANs and q-tag trunk routers and so on (It will just look like a big cloud of junk connected off an assumed switch). Is there any kind of cunning trick to detect standard layer2 switches along a path without stuff like STP?

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Inventory and workflow management systems
by vijay gill 26 May '13

26 May '13

What software solution do people use for inventory management for things like riser/conduit drawdown, fiber inventory, physical topology store, CLR/DLR, x-connect, contracts, port inventory, etc. Any experiences in integrating workflow into those packages for work orders, modeling, drawdown levels, etc. /vijay

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Re: Re: What is the most standard subnet length on internet
by 정치영 03 Aug '09

03 Aug '09

Suresh, Yes, I guess my concern is close to the second meaning. It seems so simple. Currently annoucement of /24 seems to be okey, most upstream providers accept this. However I wonder if there is any ground rule based on any standard or official recommandation. If there is some standardized rule about prefix length to be annouced, I will make my bgp & IP allocation policy of each data center of my company, and I will be able to more fairly and squarely speak to my customer like this "You have to change your server's IP address if you want move your server to other place" chiyoung ============================================= Chi-Young Joung SAMSUNG NETWORKS Inc. Email: lionair(a)samsung.com Tel +82 70 7015 0623, Mobile +82 17 520 9193 Fax +82 70 7016 0031 ============================================= ------- Original Message ------- Sender : Suresh Ramasubramanian<ops.lists(a)gmail.com> Date : 2008-12-19 12:37 (GMT+09:00) Title : Re: What is the most standard subnet length on internet Chi Young, let me clarify one thing here .. Do you mean IP allocation as in subnet allocation, swipping in apnic or through a rwhois server etc? Or do you mean "what is the minimum subnet size I can announce on the internet and have other providers not drop it on the floor"? srs On Fri, Dec 19, 2008 at 8:10 AM, 정치영 <lionair(a)samsung.com> wrote: > Hi everyone, > > I'm going to rebuild IP allocation policy of my company and I am looking for some standard reference for my policy. > I have already studied some standard like RFC1518, RIPE181, RFC2050 and I got it is very important to maintain hierachy structure. > However, what I am really wondering is what is the most standard subnet length that always can be guaranteed through Internet. less than /24 bit ? > I could not find any documents about that, which subnet length is most proper value and pursue internet standard policy ? >

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Re: Re: What is the most standard subnet length on internet
by 정치영 26 Jul '09

26 Jul '09

Hi all, I appreciate many people gave me advices, Some of persons asked me about my questions, I'm sorry for that I couldn't reply to everyone. Because of your help, I could get many opinions and standards regarding IP allocation policy. by the way, in APNIC's IP allocation sizes policy, there is a comments like below. "Below are the minimum sizes for allocations and assignments, This information is provided at the request of the ISP community to assist in filtering policy decisions " Currently, is there any provider filtering routes under LIR's minimum allocation size such as /22 ? Best regards, ============================================= Chi-Young Joung SAMSUNG NETWORKS Inc. Email: lionair(a)samsung.com Tel +82 70 7015 0623, Mobile +82 17 520 9193 Fax +82 70 7016 0031 ============================================= ------- Original Message ------- Sender : Danny McPherson<danny(a)tcb.net> Date : 2008-12-21 02:42 (GMT+09:00) Title : Re: What is the most standard subnet length on internet On Dec 18, 2008, at 9:43 PM, 정치영 wrote: > Suresh, > > Yes, I guess my concern is close to the second meaning. > > It seems so simple. Currently annoucement of /24 seems to be okey, > most upstream providers accept this. > However I wonder if there is any ground rule based on any standard > or official recommandation. > If there is some standardized rule about prefix length to be > annouced, I will make my bgp & IP allocation policy of > each data center of my company, and I will be able to more fairly > and squarely speak to my customer like this > "You have to change your server's IP address if you want move your > server to other place" Some useful guidance is provided here (and in subsequent references) as well: An Architecture for IP Address Allocation with CIDR <http://tools.ietf.org/html/rfc1518> Classless Inter-Domain Routing (CIDR): an Address Assignment and Aggregation Strategy <http://tools.ietf.org/html/rfc1519> Network Renumbering Overview <http://tools.ietf.org/html/rfc2071> A Framework for Inter-Domain Route Aggregation <http://tools.ietf.org/html/rfc2519> HTH, -danny

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Leap second tonight
by Kevin Day 18 Mar '09

18 Mar '09

Just a reminder that there's a leap second tonight. Last time I watched for what happened on 01/01/2006, there was a little bit of chaos: http://markmail.org/message/cpoj3jw5onzhhjkr?q=%22kevin+day%22+leap+second+… I've been told that some of the causes of these problems are fixed on any reasonably recent ntp distribution, but just in case, you might wanna keep an eye out if you're seeing any weirdness. The worst damage I'd heard from anyone after that event was their clock being significantly off for several hours. -- Kevin

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What to do when your ISP off-shores tech support
by Matthew Black 11 Jan '09

11 Jan '09

I've had difficulties reaching anyone with a brain at my DSL provider Verizon California. I can reliably ping the first hop from my home to the CO with a 25ms delay. But if I ping any other location, packets get dropped or significantly delayed. To me, this sounds like Verizon has an internal routing problem rather than a problem with my phone line. Note that it rained recently in our area and the cable vault in front of my is usually covered with stagnant water because the gutters don't drain it away. I have tried to explain this to tech support but they refuse to go off script, even the supervisors. They keep insisting on sending a tech to my home when I suggest this should be escalated to their network operations team. Anyhow, if I can reliably ping the first hop from my home, would that eliminate my telephone connection as part of the problem? Just a sanity check on my part. Thanks. matthew black california state university, long beach

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IPv6: IS-IS or OSPFv3
by devang patel 05 Jan '09

05 Jan '09

Hello, I do have some confusion about which one is better for IPv6 in Service Provider networks as far as IP routing and MPLS application is concern! 1. Which protocol should i use to support the IPv6 in network: ISIS or OSPFv3? As ISIS has multi-topology feature that can give us capability to run IPv4 network separate from IPv6 right! and same thing with OSPF: OSPFv2 will be used for IPv4 routing and OSPFv3 will be used for IPv6 routing! again Its look like resource utilization for both the protocol will be same as they are going to use separate database for storing the routing or topology information. ISIS still has advantage over OSPF as it does use the TLV structure which can help in expanding network to support the new feature! 2. MPLS is not distributing label for IPv6 protocol so again there will not be any IGP best path calcuated for any MPLS related application for IPv6! 3. what if i have already running OSPFv2 for IPv4 in the network then should i think for migrating to ISIS? if yes then what are the advantages that I can look at for migrating my network to IS-IS? regards Devang Patel

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Re: Leap second tonight
by Peter Lothberg 31 Dec '08

31 Dec '08

INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 e-mail : services.iers(a)obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 4 July 2008 Bulletin C 36 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of January 2009 A positive leap second will be introduced at the end of December 2008. The sequence of dates of the UTC second markers will be: 2008 December 31, 23h 59m 59s 2008 December 31, 23h 59m 60s 2009 January 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2006 January 1, 0h UTC, to 2009 January 1 0h UTC : UTC-TAI = - 33s from 2009 January 1, 0h UTC, until further notice : UTC-TAI = - 34s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC or to confirm that there will be no time step at the next possible date. Daniel GAMBIS Head Earth Orientation Center of IERS Observatoire de Paris, France

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Failover solution using BGP
by Naveen Nathan 31 Dec '08

31 Dec '08

Hi, I would appreciate insight and experience for the following situation. I have a client that would like to announce a /18 & /19 over BGP in Sacramento and LA, us being the second location in LA. Our location will be a failover location incase Sacramento goes down. They want failover for extreme cases when they're completly down in Sacramento. They have strict requirements so that traffic to their blocks should exclusively go to Sacramento or LA. This seems difficult to automate and they are aware of this. They will contact their provider to stop announcing the blocks and subsequently contact us to announce their routes. I am wondering is there a better way to approaching the situation without resorting to announcing the routes when the client calls us and tells us to failover. This seems to be the inherent problem aswell because the customer wants this to be a manual process. -- Naveen Nathan To understand the human mind, understand self-deception. - Anon

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Re: IPv6: IS-IS or OSPFv3
by David Freedman 31 Dec '08

31 Dec '08

>For IS-IS, highly recommend MT to avoid any nasties while >turning up v6 in a dual-stack environment. Also when doing MT on cisco, configure "no-adjacency-check" under the v6 address-family during the migrate else you will bounce your sessions. Cisco of course warn you against doing this but without it the change is bumpy. >From the cisco docs: "Disabling the adjacency-check command can adversely affect your network configuration. Enter the no adjacency-check command only when you are running IPv4 IS-IS on all your routers and you want to add IPv6 IS-IS to your network but you need to maintain all your adjacencies during the transition. When the IPv6 IS-IS configuration is complete, remove the no adjacency-check command from the configuration." source: http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-is-is.html ------------------------------------------------ David Freedman Group Network Engineering Claranet Limited http://www.clara.net

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