Re: [RAM] Comment on draft-farinacci-lisp-00.txt (LISP)

[Eliot Lear <lear at cisco.com>]

Yakov Rekhter wrote:
> If an ISP does not use LISP for TE, then according to the above
> none of the ISP's routers have to be modified, which means that such
> an ISP does not need to deploy any ITRs/ETRs. And if neither hosts nor 
> local routers have to be modified, then none of the local routers
> need to be ITRs/ETRs. So, where would the ITRs/ETRs be deployed ?
>  
Let's distinguish ITRs and ETRs.  ETRs are only needed by those who 
advertise (through whatever means) LISP-based address space.  ITRs MUST 
be deployed by either ISPs. their "upstreams" (for some value of 
"upstream") or their customers in order to route to PI LISP participants 
whose routes have been withdrawn.  Any one of those three models might 
suit a given situation.  Take for instance a multihomed customer with 
full BGP routing, who is already running an ETR.  Perhaps it makes sense 
for that customer to take on the ITR functionality as well, so that they 
can optimize routing.  OTOH, a large ISP may want to deploy ITRs either 
at the PE or some place nearby for their customers.  Or, a small ISP 
might make use of an upstream ITR.

There are probably other games available, as well.

Eliot

_______________________________________________
RAM mailing list
RAM at iab.org
https://www1.ietf.org/mailman/listinfo/ram