Joe, see below On 7/6/2011 1:14 PM, Joe Touch wrote: > Hi, Lou, > > On 7/6/2011 9:49 AM, Lou Berger wrote: >> Joe, >> I really like& agree with much of what you say, particularly WRT >> openflow, forces, and VPNs. >> >> I think some potentially interesting topics for discussion would be: >> - the differences (in requirements) between a VN and an overlay network >> (VPNs are just one type of overlay network after all), > > Well, my view is that a VN is an overlay (just different names). I suspect that a VN is a special case of an overlay, e.g., perhaps in it's dynamic membership/instantiation properties. > A VPN > is a *partial* VN or overlay. I don't know of a kind of overlay I'd say > wasn't a VN - can you give an example? I guess the answer depends on your definition of a VN. Do you have a good formal definition handy? I'd love to see one we can all agree to. (Which was sort of the aim of the question.) > >> - the requirements for the control interface at the VN/overlay-provider >> boundary. > > That implies something like a PPVPN - i.e., a partial overlay setup by a > provider. Not necessarily, there are lots of overlay types and control protocols/interfaces to support them. For example MPLS hierarchy and ethernet vlans are both examples of overlay technologies that can be dynamically controlled. > > IMO, "provider" is a term of economics, not architecture. Okay, that's a legitimate usage. I was using more generally to cover the case to refer to include the mechanisms used to instantiate and transport/support the overlay. Do you have an alternate term? The ITU-T likes the terms client and network... > I do agree > that the "interface to configure/control a VN" is interesting, but > that's just 'yet another network management issue'. It seems, AFAICT, to > be driven more by net mgt than by VN issues. I may be biased by my other activities, but I don't see a reason why this can't also include a control plane based interface. Lou > > Joe > >> On 7/6/2011 11:51 AM, Joe Touch wrote: >>> Hi, all, >>> >>> (speaking as an individual participant) >>> >>> On 7/6/2011 2:44 AM, Roland Bless wrote: >>> ... >>>>> We had the last meeting at the Beijing IETF meeting and also some lively discussion afterwards. >>>>> >>>>> One of the areas of discussion was (amongst many others): >>>>> - openflow vs. forces >>>>> - how forces would fit in virtual networks >>>> >>>> I see both technologies mainly focused on control plane / data plane >>>> separation. >>> >>> I agree, and don't see either as particularly relevant to VNs. They're >>> implementation issues, AFAICT. The more relevant technology to me is >>> router virtualization. >>> >>>>> - do we need tunnel headers for virtual networks on the wire or not? >>>> >>>> That depends on the substrate technology, some allow to embed a "VNet >>>> Tag" to identify different virtual links, e.g., VLAN-Tags in Ethernet >>>> headers. >>> >>> Again, this is an implementation issue. I would expect some sort of >>> indicator of VN, which can be buried inside an existing header or can >>> require an additional header. >>> >>>>> - definition of acid tests >>>> >>>> Not only definition of acid tests, but also definition of >>>> terms. For instance, how differ traditional VPNs from Virtual >>>> Networks in the context of network virtualization? IMHO current >>>> VPN solutions concentrate mainly on virtual links, advanced concepts >>>> consider virtual nodes as active elements. >>> >>> IMO, a VPN extends an existing network to add a new node, or ties two >>> existing networks together, i.e., it's a way to add a single private >>> link to a new node. >>> >>> Further, VPN nodes are always a member of exactly one VPN. >>> >>> A PPVPN is a network provided by another party (the provider) so that >>> users can join it via basically conventional VPN methods. >>> >>> I don't think of VPNs as addressing either link or router multi-use, either. >>> >>> None of this is true of VNs, IMO - a VN is a complete E2E network, can >>> coexist with many other VNs (even to the same endpoint nodes), etc. >>> >>> > How do OpenFlow concepts fit >>>> into the classification? >>> >>> IMO, Openflow is a tool; it does not define a network architecture. It >>> can be useful in moving some network issues elsewhere (e.g., allowing a >>> non-VPN capable node to join a VPN, or helping to implement router >>> virtualization outside a router that doesn't support it). I don't see >>> Openflow as anything other than one of many tools here - and one I've >>> never needed to develop VNs (if others do, I'd be glad to hear why). >>> >>>>> What do you see is important for the RG right now or what is missing? >>>> >>>> See above, but maybe we should also consider questions such as >>>> what interfaces and protocols are needed for creating inter-provider >>>> virtual networks. >>> >>> That seems to presume we know what an intra-provider VN is, and I'm not >>> sure we're all on a single page there... ;-) >>> >>> Joe >>> _______________________________________________ >>> vnrg mailing list >>> vnrg at irtf.org >>> https://www.irtf.org/mailman/listinfo/vnrg >>> >>> >>> >>> > > > >
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