Re: [Isis-wg] Re: Inconsistent view of routers over a LAN
Naiming Shen <naiming@REDBACK.COM> Tue, 10 June 2003 21:14 UTC
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Date: Tue, 10 Jun 2003 14:14:20 -0700
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From: Naiming Shen <naiming@REDBACK.COM>
Subject: Re: [Isis-wg] Re: Inconsistent view of routers over a LAN
Comments: To: Cheng-Yin.Lee@alcatel.com
Comments: cc: Tony Li <Tony.Li@procket.com>, Jeff Learman <jlearman@cisco.com>, isis-wg@ietf.org, Acee Lindem <acee@redback.com>, l2vpn@ietf.org
To: OSPF@PEACH.EASE.LSOFT.COM
In-Reply-To: Mail from "Cheng-Yin Lee" <Cheng-Yin.Lee@alcatel.com> dated Tue, 10 Jun 2003 16:43:12 EDT <3EE642E0.F617107F@alcatel.com>
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i don't think l2vpn wg needs to do much. when use link-state igp in those places, ALWAYS assume it's unreliable. just use p2p. period. ] Jeff, Tony, Acee, ] Thanks for your clarification. ] L2VPN WG is defining emulated LAN (and broadcast network for IP traffic) ] service over IP/MPLS network and some of the mechanims being defined can ] result in loss of communication among a subset of routers on the ] emulated LAN (even if all the nodes in the underlying IP/MPLS transport ] network are reachable). ] Some of the discussions have been how tolerable are routing protocols to ] this type of problem, if it is worth fixing some L2VPN WG mechanisms to ] prevent this problem, how feasible are these L2VPN solutions, are these ] not well-known problems ... ] ] I hope the L2VPN WG would consider these issues and requirements in the ] L2VPN solutions. ] Perhaps a more detailed understanding of how things work/don't work may ] help L2VPN WG develop/appreciate solutios that will work well with ] routers for e.g, in case of (i) below, what would an emulated LAN user ] observe in the routed network (is this predictable/unpredictable?) ] ] Thanks ] Cheng-Yin ] p.s I have cced l2vpn, but pls feel free to respond only to the relevant ] WG as is appropriate. ] ] Tony Li wrote: ] > ] > We should also point out that in case i) things are truly broken and ] > in case ii) the DR will not form an adjacency with A and the protocols ] > will be able to tell that things are broken. ] > ] > Tony ] > ] > | -----Original Message----- ] > | From: Jeff Learman [mailto:jlearman@cisco.com] ] > | Sent: Tuesday, June 10, 2003 9:29 AM ] > | To: Cheng-Yin.Lee@alcatel.com ] > | Cc: Mailing List; isis-wg@ietf.org ] > | Subject: Re: [Isis-wg] Re: Inconsistent view of routers over a LAN ] > | ] > | ] > | ] > | This violates the transitivity requirement stated in ISO 10589. ] > | You can't run ISIS on a subnetwork where this happens. ] > | At least, that's the theory ;) ] > | ] > | At 11:52 AM 6/10/2003, Cheng-Yin Lee wrote: ] > | >Hello, ] > | >Just got some private responses, perhaps I should clarify. ] > | >This is in context of an emulated LAN, and I am not ] > | looking for a fix in ] > | >routing protocols. ] > | > ] > | >Thanks ] > | >Cheng-Yin ] > | > ] > | >Cheng-Yin Lee wrote: ] > | >> ] > | >> Hello, ] > | >> What happens if for some reason Router A can't reach ] > | Router B, but ] > | >> Router C can reach A & B (and vice-versa), when Router A,B,C are ] > | >> connected over a broadcast network or LAN. ] > | >> ] > | >> E.g. in the case for (OSPF and IS-IS) where: ] > | >> i) C is the DR ] > | >> ii) B is the DR ] > | >> ] > | >> Thanks ] > | >> Cheng-Yin ] ] ] > Hi Cheng-Yin, ] > ] > What I've recommended in the past for these situations is to force ] > the routing protocol to view the underlying network as a P2MP ] > (Point-to-Multi-Point) network. Many vendors support this. For ] > example, in our implementation you'd simply configure: ] > ] > router ospf 1 ] > area 0 ] > interface backbone ] > network-type point-to-multipoint ] > o ] > o ] > < the rest of the OSPF config> ] > o ] > ] > Good Luck, ] > Acee ] _______________________________________________ ] Isis-wg mailing list ] Isis-wg@ietf.org ] https://www1.ietf.org/mailman/listinfo/isis-wg - Naiming
- Re: [Isis-wg] Re: Inconsistent view of routers ov… Cheng-Yin Lee
- Inconsistent view of routers over a LAN Cheng-Yin Lee
- Re: Inconsistent view of routers over a LAN Cheng-Yin Lee
- Re: Inconsistent view of routers over a LAN Acee Lindem
- Re: [Isis-wg] Re: Inconsistent view of routers ov… Naiming Shen
- Re: [Isis-wg] Re: Inconsistent view of routers ov… Cheng-Yin Lee