Another question: What does the Map Server do if it gets a request for a shorter prefix than it has an EID for. E.g., I have a mapping for 10/8 (and nothing else) but I get a request for 10/4. The text in S 5.5 suggests that I return an empty locator set. Is that correct?
On Wed, Feb 6, 2019 at 6:11 PM Eric Rescorla <[email protected]> wrote: > I'm trying to piece together the algorithm in 6833-bis S 5.5 > for Map-Replies. The text says: > > A Map-Reply returns an EID-Prefix with a mask-length that is less > than or equal to the EID being requested. > > So, consider the case where an MS has two mappings: > > 10/8 -> ETR1 > 11/8 -> ETR2 > > If the Map-Request is for 10.0.0.1, then I would return > > 10/8 -> ETR1 > > Now consider what happens when I have three mappings: > > 10/16 -> ETR1 > 10.0.2/24 -> ETR3 // New > 11/16 -> ETR2 > > Now we turn to the remainder of this section: > > When an EID moves out of a LISP site [I-D.ietf-lisp-eid-mobility], > the database mapping system may have overlapping EID-prefixes. Or > when a LISP site is configured with multiple sets of ETRs that > support different EID-prefix mask-lengths, the database mapping > system may have overlapping EID-prefixes. When overlapping EID- > prefixes exist, a Map-Request with an EID that best matches any EID- > Prefix MUST be returned in a single Map-Reply message. For instance, > if an ETR had database mapping entries for EID-Prefixes: > > I'm having trouble parsing this, but what I get out of the example > is that the Map-Response is supposed to contain the EID-prefix that > best matches the request, plus whatever exceptions would be required > to create a correct routing table. So, that would mean in the case > where the Map-Request contains 10.0.0.1, the MS would have to reply > with: > > 10/16 -> ETR1 > 10.0.2/24 -> ETR3 // New > > The first of these is necessary to provide correct routing information > for the requested prefix and the second to avoid providing incorrect > routing information for 10.0.2.1. > > Do I have this correct? It seems like the alternative is that the MS > or ETR synthesize a new, more specific prefix. Is that what's intended > instead? The example in S 5.5 suggests otehrwise, but perhaps I am > misunderstanding. > > Thanks, > -Ekr > > > > > > > > > > > >
_______________________________________________ lisp mailing list [email protected] https://www.ietf.org/mailman/listinfo/lisp
