On Apr 11, 2011, at 8:15 AM, Luigi Iannone wrote: > > On 11, Apr, 2011, at 15:37 , Owen DeLong wrote: > >> >> On Apr 11, 2011, at 6:30 AM, Luigi Iannone wrote: >> >>> >>> On 11, Apr, 2011, at 15:17 , Owen DeLong wrote: >>> >>> [snip] >>>>>> >>>>>> Doing IPv4 LISP on any kind of scale requires significant additional >>>>>> prefixes which at this time doesn't seem so practical to me. >>>>> >>>>> This is not accurate IMO. To inject prefixes in the BGP is needed only to >>>>> make non-LISP sites talk to LISP sites. Even there you can aggressively >>>>> aggregate, as explained in draft-ietf-lisp-interworking. >>>>> >>>>> As long as the LISP deployment progress you can even withdraw some >>>>> prefixes from the BGP infrastructure and advertise only a larger >>>>> aggregate in order for legacy site to reach the new LISP site. >>>>> >>>>> Luigi >>>>> >>>> Who said anything about BGP? I was talking about the amount of additional >>>> IP space needed vs. the >>>> amount of IPv4 free space remaining. >>>> >>> >>> Sorry. I misunderstood. >>> >>> But can you explain better? Why should LISP require more IP space than >>> normal IPv4 deployment? >>> >>> If you are a new site, you ask for an IP block. This is independent from >>> whether or not you will use LISP. >>> >> Sure, but, if you also need locators, don't you need additional IP space to >> use for locators? > > No, those are the IP address that you provider gives to your border router. > Right... In addition to my provider independent addresses... That's more address space than is required if I am not using LISP.
>> >>> If you are an existing site and you want to switch to LISP why you need >>> more space? you can re-use what you have? >>> >> Perhaps I misunderstand LISP, but, I though you needed space to use for >> locators and space >> to use for IDs if you are an independently routed multi-homed site. > > Not exactly. You do not need more space. You re-use what you have. > Still confused, then. This seems antithetical to what you said above and below... >> >> If you are not an independently routed multi-homed site, then, don't you >> need a set of host IDs >> to go with each of your upstream locators? >> >> As I understand LISP, it's basically a dynamic tunneling system where you >> have two discrete, >> but non-overlapping address spaces, one inside the tunnels and one outside. >> >> If that's the case, then, I believe it leads to at least some amount of >> duplicate consumption of >> IP numbers. >> > > No true. I ask for a PI block that I will use as EID-Prefix, then the > locators are part of the address space of my providers. > There is no duplication. > > Right... Ordinarily, without LISP, I get a PI block and use that for EID and the routing is based on the EID prefix. With LISP, the EID prefix is PI and I use additional PA resources to do the routing locators. That's what I meant by duplication. There are additional PA resources required on top of the PI in order to make LISP work. >>> Or I missed the point again? >>> >> Or perhaps the complexity of LISP in the details still confuses me, despite >> people's insistence >> that it is not complex. >> > > IMHO it is very simple. As any new technology there is just a learning curve > to follow, but for LISP it is not steep ;-) > I'd agree with you if it weren't for the fact I keep thinking I just about understand LISP and then get told that my understanding is incorrect (repeatedly). Owen > Luigi > > >> Owen >> >>> thanks >>> >>> Luigi >>> >>> >>> >>>> Owen >>>> >>> >> >
