DY and I are going private. If anyone wants a summary of this discussion DY will provide one.
Dino On Jul 17, 2014, at 2:14 PM, DaeYoung KIM <[email protected]> wrote: > On Thu, Jul 17, 2014 at 10:33 PM, Dino Farinacci <[email protected]> wrote: > > > On Thu, Jul 17, 2014 at 10:03 PM, Dino Farinacci <[email protected]> > > wrote: > > But when an EID is assigned to a node (either static or via DHCP) > > > > Is there a case in LISP that EID would be assigned to its interface rather > > than to a node? > > That is independent of LISP. > > Yes, in principle. But if you'd maintain the assertion (if such an assertion > has ever been made) that the network elements within a site doesn't change, > it would automatically assumed that > > - nodes in a site maintains the IP address (already) assigned, and > - the IP addresses would have been assigned to the interfaces. > > And a node can have multiple EIDs if one chooses to do that. In fact, a > dual-stack host will have two EIDs, one IPv4 and one IPv6. > > This multiple EIDs for a node is not my immediate concern in this discussion. > I'm try to confine myself to the most basic model of LISP, in order better to > understand it. > > > Somewhere, it is said that the behavior of network elements within a site > > doesn't change, which is thought to be one of the major strong feature of > > LISP. If that is the case, then the EID would be assigned to the interface > > like with the current Internet. > > Right, there are no requirements how EIDs are assigned locally within a > system. Remember, the EID is on a unchanged host. From that host's point of > view, it is just an address. From the LISP site's point of view, that address > is reachable via local routing. > > This means... (if an EID is assigned to an interface)... the e2e transport > connection would break if a node move from one subnet to another within a > site. LISP doesn't contribute to solving/improving the intra-site mobility. > Right? > > > Assuming you really meant the node, not the interface, which existing > > mechanism would allow the mobility? OSPF or ISIS? > > What I meant is the "IP address" is moving. Saying it that way means no > matter how it is assigned on the local device, what is moving is the IP > address. > > I'm still in the same hole. Does this IP address change when a node moves > from one subnet to another or not? > > > If you meant, in fact, the interface but not the node in your discussion of > > the EID assignment, do you mean a MIP like mechanism would provide the > > mobility within a site? > > I didn't and don't need to make that distinction. > > So, you don't care about the intra-site problems at all. You focus on the > inter-site routing, don't you? > > The whole idea of LIS(locator/id separation) is to solve, among many things, > the mobility problem. To ensure that, an ID would be kept constant at moving > of a node while locator would be updated at every such moving. Am I correct? > > However, if behavior of the all network elements within a site doesn't have > to change, as asserted somewhere in the main documents, (this would mean that > ARP is also at work as usual), the ID (in fact, the IP address) would change > at any such moving, which would not keep the EID constant. Such move would > not only break a intra-site connection but also a connection between sites. > > So, you cannot just ignore the intra-site problems. If the EID(IP address) > has to change at every node moving across subnets within a site, the whole > purpose of ID (in LIS) would be questioned. Isn't this in contradiction to > the whole idea of LIS? > > If the EID would be kept constant even at moving within a site, then some > network elements within a site have to change their behavior, don't they? > Even the host behavior might have to change like, for example, shutting off > the ARP operation. > > Also, EIDs can be flat, as with other usual LIS proposals, and need not > necessarily be out of a power-of-2 EID prefix. Correct? > > > So in the static case, that would mean a host route would need to be > > injected into the IGP if the node's address stays the same > > > > I cannot catch what you exactly mean here by 'injection'. Sorry... > > When a host 10.1.1.1 moves off subnet 10.1.0.0/16 to subnet 11.1.0.0/16, the > routers attached to 11.1 need to advertise a 10.1.1.1/32 route into the > routing system. > > Got it. This is exactly what ISIS is doing, right? > > > So, in short, what mobility solution is provided by LISP in addition to the > > existing mobility mechanisms? > > There are different scopes of mobility. When you roam across LISP site, you > use LISP mobility. > > You mean the tunneling..? Tunneling implicitly provides some sort of > mobility... like that? > > When you roam within LISP sites you use IP-mobility or host routes. > > So, no additional contribution by LISP as far as intra-site mobility is > concerned. Right? > > -- > DY _______________________________________________ lisp mailing list [email protected] https://www.ietf.org/mailman/listinfo/lisp
