Dino Farinacci <[email protected]> writes: > > Scenario 1: Bare metal server has 2 separate connections to two > > different boxes. How are these two connections presented to the > > (bare-metal) TS?
> I am going to fail at describing this with the NVO3 terminology. A > TS to me is a site, that has lots of hosts, switches, routers in > it. They are addressable. I call those addresses EIDs. So we are > talking about a single EID. An IP address assigned to a bare-metal > server that has two connections, one to each physical NVE. A TS is Tenant System. E.g., a VM on virtualized host, or the bare metal server in your original example. The NVE is normally very close to the TS, i.e., on the same server, or offloaded to the ToR. > > 1A) two different interfaces are visible to the TS, both with their > > own separate IP addresses. This is not an issue for NVO3, since this > > is modeled as two interfaces to two separate VNs. (Right?) > I can't answer this because I am not sure you and I agree on what a > TS is. I am not disagreeing how NVO3 defines a TS but I think it is > not specific enough for this context. TS is a single host endpoint. It connects directly to a virtual network through an NVE. > > B) TS sees only one interface, the CNA hides the details of two > > physical uplinks from TS. Links could be active/active or > > active/backup. In this case, the TS has one IP adddress (I presume) > > with the CNA hiding the details of multiple uplinks from the TS. > > > > This is a messier case... Do both uplinks have to connect to the same > > NVE? In the standard L2 case, don't both L2 uplinks have to connect to > > the "same L2 network"? That only means that both ToRs would need to > > support the same VLANs and connect to the same LAN domains. (Right?) > Yes, they have to connect to the same L2 network. The difference is in the L2 case, you can send a packet up either uplink and things generally work (you may still have to deal with MAC flapping concerns). In the NVO3 case, if the two upstream NVEs are different, they will have their own IP addresses and the tunnel source for packets they send to remote NVEs will be different depending on which NVE is the sender. > > If above we allow the two uplinks to go to two different NVEs, the > > implication is that from an NVO3 perspective, a given TS mapping is > > reachable through different NVE addresses. That raises all sorts of > > interesting questions. :-) > This called multi-homing. ;-) That is equivalent to a LISP EID that > has a locator-set. The reason there is a locator-set is because > there can be multiple RLOCs (read: NVEs) used reach the EID. Right. The WG just hasn't had much discussion about whether NVEs need to be multi-homed. So we don't really have a position yet. > > Is this something we need to support? I agree it has some > > benefits. But it also adds some complications... > > > > Thomas > It depends how close topologically the NVE is to the endpoint. If > the NVE was in the application, then for the same IP address there > would be multiple NVEs. So the point could be taken to an extreme. In the virtualized case, the NVE is on the same server as the VM/TS. In the bare metal case, the NVE is offloaded onto an adjacent device (e.g., ToR), but is still quite close. Thomas _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
