RE: [L1vpn] Issues and concerns about Basic Mode OSPF Discovery
Dimitri.Papadimitriou@alcatel.be Sat, 13 May 2006 08:50 UTC
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To: Don Fedyk <dwfedyk@nortel.com>
Subject: RE: [L1vpn] Issues and concerns about Basic Mode OSPF Discovery
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hi don in general i see where you are landing at but there is also an issue that for me - but probably for others - is not clear by definition there are requirements that any solution should cover since at the root of what a VPN discovery mechanism implies - these are part of the base mode (PE-to-PE VPN membership info. exchange) *** even if the requirement doc does not say a word about this *** i am looking at the requirement document the group has produced - see section 7 and 8 & i see four models, each with different implications on the PE-to-PE information exchange (these models are referred to as enhanced mode(s): a) Overlay extension service model b) Virtual node service model c) Virtual link service model d) Per-VPN peer service model a) is the natural extension of membership information exchange b/w CEs ... but what about b), c) and d) ... so in terms of solution we are confronted to the following issue OSPF vs BGP solving the same or non-necessarily identical problems ? i am quite surprised this discussion happens now because the document <http://www.ietf.org/internet-drafts/draft-ietf-l1vpn-applicability-01.txt> was initially intended to answer to these questions, in part. when it comes the identification on the impact in selecting a specific protocol sol. vs proposed service models; however, this doc. mentions at several places "Detailed analysis is for further study." including the base "VPN membership information exchange within the provider network" see Section 6.1.3 so, the discussion we're having simply shows that we're not mature enough to cover more than the base discovery mode and before stepping toward enhanced modes we certainly need to complete these FFS - the important point is that before completing this work it is certainly more than premature to state than one size fits all thanks, - dimitri. "Don Fedyk" <dwfedyk@nortel.com> 12/05/2006 18:08 To: "Igor Bryskin" <ibryskin@movaz.com>, "Drake, John E" <John.E.Drake2@boeing.com>, "Acee Lindem" <acee@cisco.com> cc: l1vpn@ietf.org Subject: RE: [L1vpn] Issues and concerns about Basic Mode OSPF Discovery Hi Igor Please note I think that we have to step back and look a requirements. I see a mixture of auto discovery and path computation requirements all being mixed together. Auto Discovery IMO has the requirement to learn and distribute VPN members. There is also an optional requirement of targeting VPN information where PE switches are the only nodes that learn VPN membership and that they do so only when they participate in the VPN. There is another optional requirement that the distribution of VPN information can be controlled by policy -- and I think this is where we start to get confused. The BGP mechanisms that I understand do this abstract from the physical topology but they are capable producing certain connectivity. However as you point out there are additional requirements due to the physical nature of L1 when setting up an L1VPN which also affects the topology. At this point I would say these are for future (perhaps near future) study. But these functions are common regardless of how VPN membership is obtained. So I think we should cap VPN discovery at learning and distributing Membership and then we should look at when we set up L1VPN how we deal with additional constraints. Some of these are topological, some are resource based and some are VPN specific IMHO, but I think we can still use general mechanisms to address these. Regards, Don > -----Original Message----- > From: Igor Bryskin [mailto:ibryskin@movaz.com] > Sent: Friday, May 12, 2006 10:59 AM > To: Drake, John E; Acee Lindem > Cc: l1vpn@ietf.org > Subject: Re: [L1vpn] Issues and concerns about Basic Mode > OSPF Discovery > > > -----Original Message----- > > From: Igor Bryskin [mailto:ibryskin@movaz.com] > > Sent: Friday, May 12, 2006 7:20 AM > > To: Drake, John E; Acee Lindem > > Cc: l1vpn@ietf.org > > Subject: Re: [L1vpn] Issues and concerns about Basic Mode OSPF > Discovery > > > > > > > > IB>> I have already answered to this. In the context of the L1VPNs > > only > > > PEs > > > are the users of the TE info, because only them who perform path > > > computation, and the only purpose of TE info distribution is to > enable > > the > > > path computation. Likewise PEs are the only users of the L1VPN > > > information. > > > So I don't see any conceptual difference between L1VPN and TE > > applications > > > in this respect. > > > > > > > In the TE case, the PEs require the information about the > Ps' links in > > order to perform CSPF, so the PEs and the Ps are working > cooperatively. > > This is not the same as the L1VPN case. > > > > IB>> But Ps do not use the TE information. So, from the scalability > point > > of > > view how is different from L1VPN application? > > Furthermore, in the Routing per-VPN model Ps will have to advertise > which > > L1VPNs P links belong to to enable PEs publishing per-VPN resource > layout > > to > > CEs. > > It sounds as though you are proposing that a P link is > configured with a list of the VPNs which can use it, and that > this information is advertised in the IGP. If this is what > you are proposing, I think it is a truly terrible idea. > > IB>> And why is it so? Routing per-VPN model requires that > PEs provide > IB>> the > attached CEs with info about resource availability of > Provider network on per-VPN basis, so that CEs could control > the path selection over the Provider network. You have to > configure P links (and their attributes) anyway, so you might > as well configure the VPN constraints - a simple and light > overhead that will make PEs dynamically discover which P > links belong to which VPNs. > > I have asked already: how would you accomplish this with BGP? > > Igor > > > _______________________________________________ > L1vpn mailing list > L1vpn@lists.ietf.org > https://www1.ietf.org/mailman/listinfo/l1vpn > > _______________________________________________ L1vpn mailing list L1vpn@lists.ietf.org https://www1.ietf.org/mailman/listinfo/l1vpn _______________________________________________ L1vpn mailing list L1vpn@lists.ietf.org https://www1.ietf.org/mailman/listinfo/l1vpn
- [L1vpn] Issues and concerns about Basic Mode OSPF… Adrian Farrel
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- RE: [L1vpn] Issues and concerns about Basic Mode … MEURIC Julien RD-CORE-LAN
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- [L1vpn] Issues and concerns about Basic Mode OSPF… Yakov Rekhter
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Don Fedyk
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- Re: [L1vpn] Issues and concerns about Basic Mode … Yakov Rekhter
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Drake, John E
- RE: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- RE: [L1vpn] Issues and concerns about Basic Mode … Dimitri.Papadimitriou
- Re: [L1vpn] Issues and concerns about Basic Mode … Dimitri.Papadimitriou
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- Re: [L1vpn] Issues and concerns about Basic Mode … Richard Rabbat
- Re: [L1vpn] Issues and concerns about Basic Mode … Dimitri.Papadimitriou
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Drake, John E
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Drake, John E
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Drake, John E
- RE: [L1vpn] Issues and concerns about Basic Mode … Lou Berger
- RE: [L1vpn] Issues and concerns about Basic Mode … Don Fedyk
- Re: [L1vpn] Issues and concerns about Basic Mode … Igor Bryskin
- RE: [L1vpn] Issues and concerns about Basic Mode … Dimitri.Papadimitriou
- Re: [L1vpn] Issues and concerns about Basic Mode … Acee Lindem
- Re: [L1vpn] Issues and concerns about Basic Mode … Lou Berger