Sorry to others for bothering.
On Thu, Jul 17, 2014 at 11:19 PM, Dino Farinacci <[email protected]> wrote: > 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 > > -- DY
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