Re: IPv6: IS-IS or OSPFv3
Thanks all for sharing information! regards Devang Patel On Mon, Jan 5, 2009 at 11:43 AM, Justin Shore jus...@justinshore.comwrote: Kevin Oberman wrote: I would hope you have a backbone well enough secured that you don't need to rely on this, but it does make me a bit more relaxed and makes me wish we were using ISIS for IPv4, as well. The time and disruption involved in converting is something that will keep us running OSPF for IPv4 for a long time, though. I remember the 'fun' of converting from IGRP to OSPF about 13 years ago and I'd prefer to retire before a repeat. I did the OSPF -- IS-IS migration some time back and here's some of the info I found at the time. http://www.nanog.org/meetings/nanog29/abstracts.php?pt=Njg2Jm5hbm9nMjk=nm=nanog29 Vijay did a nice presentation on AOL's migration to IS-IS. IIRC AOL migrated everything in 2 days. Day 1 was to migrate their test POP and hone their script. All remaining POPs were migrated on Day 2. I believe he said it went well. There have been several other documented migrations too: http://www.geant.net/upload/pdf/GEANT-OSPF-to-ISIS-Migration.pdf http://www.ripe.net/ripe/meetings/ripe-47/presentations/ripe47-eof-ospf.pdf I migrated my SP from a flat OSPF network (end to end area 0) to IS-IS. The OSPF setup was seriously screwed up. Someone got the bright idea to changes admin distances on some OSPF speakers, introduce a default in some places with static defaults in others, redistributing like it was going out of style, redisting a static for a large customer subnet on P2 instead of P1 which is what PE1 actually connected to (and not advertising the route from PE1 for some unknown reason), etc. The old setup was a nightmare. The IS-IS migration went fairly well after I got some major bugs worked out on our 7600s. I implemented IS-IS overtop of OSPF. Some OSPF speakers had admin distances of 80 and some were default. IS-IS slipped in over top with no problems. I raised IS-IS to 254 for the initial phase anyway just to be safe. Once I had IS-IS up I verified it learned all the expected routes via IS-IS. Then I lowered its admin distance back to the default and bumped OSPF up to 254. Shortly thereafter I nuked OSPF from each device. It was hitless. I never could get IS-IS to work with multiple areas. The 7600s made a smelly mess on the CO floor every time I tried. In the end I went with a L2-only IS-IS network. Still it works well for the most part. I've had about as much trouble with IS-IS as I have had with OSPF. Occasionally some random router will get a burr under it's saddle and jack up the MTU on the CLNS packets beyond the interface's max. The receiving router will drop the padded frame as too big. Fixing this can sometimes happen with a shut/no shut. Sometimes I can nuke the entire IS-IS config and re-add the config. Other times I simply have to reboot. This doesn't happen too often; it's usually several hours after I rock the IS-IS boat so to speak. Still, I wouldn't go back to OSPF for this SP. Justin
Re: IPv6: IS-IS or OSPFv3
On Tuesday 06 January 2009 01:43:25 am Justin Shore wrote: I never could get IS-IS to work with multiple areas. The 7600s made a smelly mess on the CO floor every time I tried. In the end I went with a L2-only IS-IS network. How so? Cheers, Mark. signature.asc Description: This is a digitally signed message part.
Re: IPv6: IS-IS or OSPFv3
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, On Dec 28, 2008, at 3:00 AM, Mark Tinka wrote: On Saturday 27 December 2008 09:27:05 pm Randy Bush wrote: as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? In practice, we realized that enabling IS-ISv6 on interfaces already running IS-ISv4 was problematic without MT pre- configured. at least in my case, I did turned ISISv6 in one WAN interface where the router on the other side (a Cisco) did not have the ipv6 unicast routing general command on and the isis adjacency went down completely. So, yes that was an issue. But if you enabled IPv6 in both ends first and then one interface at the time, it worked. I used MT to avoid IPv6 black holes during the configuration period, but as some boxes did not implemented it, I needed to use the transition option where IPv6 adjacencies are carried in both native and the MT-IPv6. Fortunately the two vendors that were lacking of MT support are up-to-date, however not in time as the migration ended and MT was removed and I left the company. Roque. - - - -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.8 (Darwin) iEYEARECAAYFAklabZkACgkQnk+WSgHpbO49PACg2Rx0yaH4owU2GA5koORD+pra kjgAoMgoXYDVD2ayWhn56fkt0urcyyAx =1tWb - - - -END PGP SIGNATURE- -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.8 (Darwin) iEYEARECAAYFAklacwUACgkQnk+WSgHpbO4TUgCfVpGEMMIdS8y0RrtNQh9rh1Ne fQcAoIOBUc2O4em8NwqwR2UJDDm1Z7Mh =YAeJ -END PGP SIGNATURE-
Re: IPv6: IS-IS or OSPFv3
On Wednesday 31 December 2008 03:14:13 am Roque Gagliano wrote: at least in my case, I did turned ISISv6 in one WAN interface where the router on the other side (a Cisco) did not have the ipv6 unicast routing general command on and the isis adjacency went down completely. So, yes that was an issue. One of the things I'm hoping Cisco can fix in not-too- distant future releases of IOS. But if you enabled IPv6 in both ends first and then one interface at the time, it worked. What we saw on our test segment was that v4 adjacencies were not torn down by merely enabling IS-ISv6 on an interface (given that JunOS enables IS-ISv6 by default when IS-IS is enabled on the router; in IOS, you have to explicitly turn IS-ISv6 on). v4 adjacencies were torn down *after* an IPv6 address was added to the interface. We witnessed this issue under both IOS and JunOS. Cheers, Mark. signature.asc Description: This is a digitally signed message part.
Re: IPv6: IS-IS or OSPFv3
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
Re: IPv6: IS-IS or OSPFv3
There is no fundamental difference between ISIS and OSPF; it's all in details and style. You might want to look at: http://www.nada.kth.se/kurser/kth/2D1490/06/hemuppgifter/bhatia-manral-diff-isis-ospf-01.txt.html Glen. On Sat, Dec 27, 2008 at 8:17 AM, devang patel devan...@gmail.com wrote: 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 resourceutilization 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
RE: IPv6: IS-IS or OSPFv3
... not to mention that fact that IS-IS is, IMHO, a much nicer IGP to work with. WRT that last sentence, that is an almost religious debate I was trying to avoid starting ... :) Well IMHO it's a very important point to consider. This is a great chance to switch your IGP, if you've ever wanted to. You *need* to And that is what I tell people too - if you are looking to change (in either direction (or others!), mind you), this could be an excuse / opportunity. deploy a new one anyways, so it's a great opportunity to see if you can simplify your network by migrating. Especially as OSPFv3 *isnt* the same as OSPFv2, so you will have to learn new things either way! Well from a pragmatic/operational perspective OSPFv3 and OSPFv2 are close enough that you would require _very_ little re-training. Oh, and I *am* in the process of organising a Crusade to wipe out those heretical OSPF supporters once and for all... ;) Funny, that is how most ISIS proponents seem to feel - but without the smiley! /TJ
RE: IPv6: IS-IS or OSPFv3
as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? In practice, we realized that enabling IS-ISv6 on interfaces already running IS-ISv4 was problematic without MT pre- configured. Those links surely lost IS-IS adjacency which threatened stability of the network. Yup, that is the rub: if rolling out your v6 routing impacts your v4 routing you are not winning. /TJ
Re: IPv6: IS-IS or OSPFv3
In practice, we realized that enabling IS-ISv6 on interfaces already running IS-ISv4 was problematic without MT pre- configured. Those links surely lost IS-IS adjacency which threatened stability of the network. Yup, that is the rub: if rolling out your v6 routing impacts your v4 routing you are not winning. this is not very deep. mark did point out how to avoid it, pointing out why mt was very useful as opposed to just another bell and whistle. during a transition, in fact, topologies are not congruent due to inability to have a flag millisecond, a very very useful observation. randy
RE: IPv6: IS-IS or OSPFv3
In practice, we realized that enabling IS-ISv6 on interfaces already running IS-ISv4 was problematic without MT pre- configured. Those links surely lost IS-IS adjacency which threatened stability of the network. Yup, that is the rub: if rolling out your v6 routing impacts your v4 routing you are not winning. this is not very deep. Is it untrue? mark did point out how to avoid it, pointing out why mt was very useful as opposed to just another bell and whistle. during a transition, in fact, topologies are not congruent due to inability to have a flag millisecond, a very very useful observation. Indeed, and not creating the problem is good thing. I don't think we are disagreeing on anything here ... Although I don't believe anyone has mentioned multi-topology + transition just yet, the goal being that when you go from ST to MT (assuming you aren't already there, that is) you don't impact ongoing operations / neighborships. /TJ
Re: IPv6: IS-IS or OSPFv3
On Fri, 26 Dec 2008, devang patel wrote: 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! Both work and have advantages and disadvantages. Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. ISIS-MT means you have to know that all your ISIS speakers will handle the MT packets gracefully. I know products from large vendors in the market which do not (IPv6 not enabled, it receives IPv6 MT packets, affects IPv4 ISIS control plane badly). -- Mikael Abrahamssonemail: swm...@swm.pp.se
RE: IPv6: IS-IS or OSPFv3
Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. I totally agree on the discrete/segregated control planes, although note that - for those who want it - OSPFv3 will soon be able to do IPv4 route exchange as well ... /TJ -Original Message- From: Mikael Abrahamsson [mailto:swm...@swm.pp.se] Sent: Saturday, December 27, 2008 6:23 AM To: devang patel Cc: nanog@nanog.org Subject: Re: IPv6: IS-IS or OSPFv3 On Fri, 26 Dec 2008, devang patel wrote: 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! Both work and have advantages and disadvantages. Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. ISIS-MT means you have to know that all your ISIS speakers will handle the MT packets gracefully. I know products from large vendors in the market which do not (IPv6 not enabled, it receives IPv6 MT packets, affects IPv4 ISIS control plane badly). -- Mikael Abrahamssonemail: swm...@swm.pp.se
Re: IPv6: IS-IS or OSPFv3
TJ wrote: Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. I totally agree on the discrete/segregated control planes, although note that - for those who want it - OSPFv3 will soon be able to do IPv4 route exchange as well ... Only if the vendors pick up on those changes. Kind regards, Martin List-Petersen /TJ -Original Message- From: Mikael Abrahamsson [mailto:swm...@swm.pp.se] Sent: Saturday, December 27, 2008 6:23 AM To: devang patel Cc: nanog@nanog.org Subject: Re: IPv6: IS-IS or OSPFv3 On Fri, 26 Dec 2008, devang patel wrote: 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! Both work and have advantages and disadvantages. Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. ISIS-MT means you have to know that all your ISIS speakers will handle the MT packets gracefully. I know products from large vendors in the market which do not (IPv6 not enabled, it receives IPv6 MT packets, affects IPv4 ISIS control plane badly). -- Mikael Abrahamssonemail: swm...@swm.pp.se -- Airwire - Ag Nascadh Pobal an Iarthar http://www.airwire.ie Phone: 091-865 968
Re: IPv6: IS-IS or OSPFv3
For IS-IS, highly recommend MT to avoid any nasties while turning up v6 in a dual-stack environment. as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? randy
Re: IPv6: IS-IS or OSPFv3
On Saturday 27 December 2008 09:08:50 pm Martin List- Petersen wrote: Only if the vendors pick up on those changes. Juniper support this since JunOS 9.2 (draft-ietf-ospf-af- alt-06.txt). Cheers, Mark. signature.asc Description: This is a digitally signed message part.
RE: IPv6: IS-IS or OSPFv3
Personally, I like the fact that IPv4 and IPv6 control plane are different, thus I'd go for OSPv3. I totally agree on the discrete/segregated control planes, although note that - for those who want it - OSPFv3 will soon be able to do IPv4 route exchange as well ... Only if the vendors pick up on those changes. Well, of course - just like anything else. That was part of the reason for the scary-quotes around soon ... /TJ
Re: IPv6: IS-IS or OSPFv3
Hi, Thanks all of you to provide your inputs on my questions! The main idea behind Multitopology in IS-IS is to enabling the IPv6 routing in the redundant part of the network so that way I will not mess around with the current IPv4 routing or services which is running or serving to customers currently! so by migrating redundant part of the topology to IPv6 using Multitopology IS-IS and make it that part as a active for IPv6 for testing how it works! and then I can enable the IPv6 on my whole network! I guess that might be the good benefit. Same thing we can do with OSPFv3 also as I can enable IPv6 routing using OSPFv3 on my redundant part of the network and after successful migration i can enable it on my whole network! But again as far as expansion is concern IS-IS is good protocol to consider. OSPF does have bit more complexity in terms of operation. again the one question is how about the router resource utilization for both the protocol if I will be running IPv6 and IPv4 in the network! One more question: do we need to enable the IPv6 on each and every router of the service provider network including P routers also? does it really required to run IPv6 on each and every router? or running it on only PE router is sufficient to support the customers needs? regards Devang Patel On Sat, Dec 27, 2008 at 10:29 AM, deles...@gmail.com wrote: Having worked for seveal SP's 'tier 1' and otherwise along with a couple of router vendors IMO MT is one of those thing people ask for just in case. Sure we _could_ always find a use for it, but we don't always look at the potential diffrent IGP topologies are going to cause for our NOC staff @ 2am over a holiday weekend when some does decide to break. -jim --Original Message-- From: Randy Bush To: Mark Tinka Cc: nanog@nanog.org Subject: Re: IPv6: IS-IS or OSPFv3 Sent: Dec 27, 2008 9:27 AM For IS-IS, highly recommend MT to avoid any nasties while turning up v6 in a dual-stack environment. as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? randy Sent from my BlackBerry device on the Rogers Wireless Network
Re: IPv6: IS-IS or OSPFv3
On Sat, 27 Dec 2008, Randy Bush wrote: as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? Personally, if my v4 and v6 topologies are not different, I'd run ISIS and not run MT. MT for me is to make v4 and v6 have different control planes (even though it's using the same protocol), thus I see little difference in running OSPFv3+ISIS, or running ISIS-MT for v4+v6. I argue that it's better to have different control planes for v4 and v6 and make it obvious (OSPv3 / ISIS), than to use ISIS-MT and obfuscate. -- Mikael Abrahamssonemail: swm...@swm.pp.se
Re: IPv6: IS-IS or OSPFv3
as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? Personally, if my v4 and v6 topologies are not different, I'd run ISIS and not run MT. MT for me is to make v4 and v6 have different control planes (even though it's using the same protocol), thus I see little difference in running OSPFv3+ISIS, or running ISIS-MT for v4+v6. I argue that it's better to have different control planes for v4 and v6 and make it obvious (OSPv3 / ISIS), than to use ISIS-MT and obfuscate. the real control plane is bgp. is-is is for recursive resolution to find bgp's next hop interface, fertig. so the simpler the better. i am annoyed enough that bgp4 and bgp6 peerings and configs are overly divergent. running a different igp for 6 and 4 would not make me happy. randy
Re: IPv6: IS-IS or OSPFv3
TJ wrote: 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! General rule of thumb - use whichever you / your operation is most familiar with. Using IS-IS today, use it for IPv6. Using OSPFv2 today, use OSPFv3 for IPv6. Well, OSPFv3 has enough differences from OSPFv2 to make switching to IS-IS a benefit to stop people making mistakes through expected operational similarity (if that makes sense). Also it means that once you're doing v6 everywhere you can dump OSPFv2 and only have one IGP for both v4 and v6. I personally think that'll save a lot of headaches down the line, not to mention that fact that IS-IS is, IMHO, a much nicer IGP to work with. adam.
Re: IPv6: IS-IS or OSPFv3
On Fri, 26 Dec 2008 20:37:41 -0800 Kevin Oberman ober...@es.net wrote: The main reason I prefer ISIS is that it uses CLNS packets for communications and we don't route CLNS. (I don't think ANYONE is routing CLNS today.) That makes it pretty secure. Unless, of course, someone one hop away -- a peer? a customer? an upstream or downstream? someone on the same LAN at certain exchange points? -- sends you a CLNP packet at link level... --Steve Bellovin, http://www.cs.columbia.edu/~smb
RE: IPv6: IS-IS or OSPFv3
... not to mention that fact that IS-IS is, IMHO, a much nicer IGP to work with. WRT that last sentence, that is an almost religious debate I was trying to avoid starting ... :) /TJ
Re: IPv6: IS-IS or OSPFv3
Steven M. Bellovin writes: Unless, of course, someone one hop away -- a peer? a customer? an upstream or downstream? someone on the same LAN at certain exchange points? -- sends you a CLNP packet at link level... True enough, and mistakenly enabling ISIS on external ports has been known to happen though in the absence of malice it usually causes no problems. If it does cause problems, generally the source can be more easily localized given that it has to be L2-adjacent to one of your routers. Joe
Re: IPv6: IS-IS or OSPFv3
TJ wrote: ... not to mention that fact that IS-IS is, IMHO, a much nicer IGP to work with. WRT that last sentence, that is an almost religious debate I was trying to avoid starting ... :) Well IMHO it's a very important point to consider. This is a great chance to switch your IGP, if you've ever wanted to. You *need* to deploy a new one anyways, so it's a great opportunity to see if you can simplify your network by migrating. Especially as OSPFv3 *isnt* the same as OSPFv2, so you will have to learn new things either way! Oh, and I *am* in the process of organising a Crusade to wipe out those heretical OSPF supporters once and for all... ;) adam.
Re: IPv6: IS-IS or OSPFv3
Date: Sat, 27 Dec 2008 15:23:25 -0500 From: Steven M. Bellovin s...@cs.columbia.edu On Fri, 26 Dec 2008 20:37:41 -0800 Kevin Oberman ober...@es.net wrote: The main reason I prefer ISIS is that it uses CLNS packets for communications and we don't route CLNS. (I don't think ANYONE is routing CLNS today.) That makes it pretty secure. Unless, of course, someone one hop away -- a peer? a customer? an upstream or downstream? someone on the same LAN at certain exchange points? -- sends you a CLNP packet at link level... You mean that someone is silly enough to enable CLNS on external interfaces? I mean, it's not by default on either Cisco or Juniper. I don't imagine any other routers do that, either. (Of course, SOMEONE is always that silly. But I hope the folks reading this are not.) -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: ober...@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 pgpPe26dUNlK1.pgp Description: PGP signature
Re: IPv6: IS-IS or OSPFv3
On Saturday 27 December 2008 09:27:05 pm Randy Bush wrote: as one who has been burned when topologies are not congruent, i gotta ask. if i do not anticipate v4 and v6 having different topologies, and all my devices are dual-capable, would you still recommend mt for other than future-proofing? In practice, we realized that enabling IS-ISv6 on interfaces already running IS-ISv4 was problematic without MT pre- configured. Those links surely lost IS-IS adjacency which threatened stability of the network. Things could probably have been easier if all routers accepted all transition commands at the same time (or if all routers were pre-configured and powered on at the same time), but that's not possible. MT allowed us to bring up individual v6 links on the same and different routers, at different times, without bringing down the v4 network, considering that several routers had as many as 4 - 6 links into the core. Cheers, Mark. signature.asc Description: This is a digitally signed message part.
IPv6: IS-IS or OSPFv3
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 resourceutilization 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
RE: IPv6: IS-IS or OSPFv3
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! General rule of thumb - use whichever you / your operation is most familiar with. Using IS-IS today, use it for IPv6. Using OSPFv2 today, use OSPFv3 for IPv6. If that isn't good enough for you, then you need to understand the operational differences between the protocols, and which aspects are most relevant to your environment. I can't answer that for you ... 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 Yes, MT could be a benefit ... but not the same thing for OSPF. be used for IPv4 routing and OSPFv3 will be used for IPv6 routing! again Its look like resourceutilization 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! ISIS is generally considered easier to extend, but OSPF has proven to be quite extensible itself ... a wash, for the most part. 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! Yes, lack of a native IPv6 control plane could be something of (cough) problem. 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? Again, IMHO this depends on way too many factors to make a simple, blanket statement. regards Devang Patel HTH! /TJ
Re: IPv6: IS-IS or OSPFv3
Date: Fri, 26 Dec 2008 19:47:21 -0700 From: devang patel devan...@gmail.com 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 resourceutilization 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? FWIW, we run OSPF for IPv4 and ISIS for IPv6. We started with ISIS for v6 because we were routing IPv6 before OSPFv3 was available. The main reason I prefer ISIS is that it uses CLNS packets for communications and we don't route CLNS. (I don't think ANYONE is routing CLNS today.) That makes it pretty secure. I would hope you have a backbone well enough secured that you don't need to rely on this, but it does make me a bit more relaxed and makes me wish we were using ISIS for IPv4, as well. The time and disruption involved in converting is something that will keep us running OSPF for IPv4 for a long time, though. I remember the 'fun' of converting from IGRP to OSPF about 13 years ago and I'd prefer to retire before a repeat. The real issue is that you need to run something you understand and can manage effectively. It that is OSPF, it will certainly do the job. If it is ISIS, it will, too. The real differences are few and not significant for most. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: ober...@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751 pgp3UjGAOmN0i.pgp Description: PGP signature
Re: IPv6: IS-IS or OSPFv3
Kevin, Thanks for pointing out other good part of having CLNS as a transport for ISIS as a security point! regards Devang Patel On Fri, Dec 26, 2008 at 9:37 PM, Kevin Oberman ober...@es.net wrote: Date: Fri, 26 Dec 2008 19:47:21 -0700 From: devang patel devan...@gmail.com 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 resourceutilization 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? FWIW, we run OSPF for IPv4 and ISIS for IPv6. We started with ISIS for v6 because we were routing IPv6 before OSPFv3 was available. The main reason I prefer ISIS is that it uses CLNS packets for communications and we don't route CLNS. (I don't think ANYONE is routing CLNS today.) That makes it pretty secure. I would hope you have a backbone well enough secured that you don't need to rely on this, but it does make me a bit more relaxed and makes me wish we were using ISIS for IPv4, as well. The time and disruption involved in converting is something that will keep us running OSPF for IPv4 for a long time, though. I remember the 'fun' of converting from IGRP to OSPF about 13 years ago and I'd prefer to retire before a repeat. The real issue is that you need to run something you understand and can manage effectively. It that is OSPF, it will certainly do the job. If it is ISIS, it will, too. The real differences are few and not significant for most. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: ober...@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
