Thanks for your responses - see below > On Jun 13, 2024, at 2:34 PM, Dino Farinacci <[email protected]> wrote: > > >>>>> >>>>> What is the precedence between the L bit and the S bit? Must they both be >>>>> set to 1? What is the procedure of L >>>> >>>> There isn't one, they are treated independently. >>> >>> PPE >>> How is the decision to skip a node taken? >>> Let’s take this example ( n (L=1, S=0, P=0), n+1 (L=1,S=1),…., etr) >>> >>> If we check S=0 first then the decision is just to Skip that hop “n” then >>> will not do a look up and go to next > > Right, if the encapsulator thinks the RLOC for n is down, it could go to n+1.
Here is where i wonder whether strict would have been best to drop the packet and not go to n+1 per the example for SFC where there are mandatory services. I think it might be worthwhile to document this behavior so as there are no surprises. Thoughts? Padma > >>> reencap hop n+1 . Get a valid RLOC by performing look up for next hops in >>> the list. (Result “n”is skipped). > > Then it looks up EID n+1 to get the RLOC for it. > >>> If we check first L = 1 and then there is a valid RLOC we use the reencap >>> hop n regardless of whether it was skippable >>> (Result here “n” is not skipped) > > Right. > >>> If S =1 then we may do a look up (Result “n” not skipped) >>> See more below on S=1 and unreachability. >>> >>> I was wondering which is the actual behavior. As the text on S=0 is a “can >>> skip” it seems implementation specific and still be ok. Should some >>> guidance on use of L and S bit be included for clarity? FWIW I have no >>> strong opinion on this. > > You have to lookup the EID when L=1, you can't tell the EID is up or not, you > have to probe its RLOC. When you do that, you can decide not to use it and > move to the second one. If the S=1 is set for this EID, then you must stop > using the ELP. > > Dino > _______________________________________________ lisp mailing list -- [email protected] To unsubscribe send an email to [email protected]
