On 19/08/15 17:46, Acee Lindem (acee) wrote: > Hi Stephen, > > On 8/19/15, 11:51 AM, "Stephen Farrell" <stephen.farr...@cs.tcd.ie> wrote: > >> Stephen Farrell has entered the following ballot position for >> draft-ietf-ospf-prefix-link-attr-12: No Objection >> >> When responding, please keep the subject line intact and reply to all >> email addresses included in the To and CC lines. (Feel free to cut this >> introductory paragraph, however.) >> >> >> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html >> for more information about IESG DISCUSS and COMMENT positions. >> >> >> The document, along with other ballot positions, can be found here: >> https://datatracker.ietf.org/doc/draft-ietf-ospf-prefix-link-attr/ >> >> >> >> ---------------------------------------------------------------------- >> COMMENT: >> ---------------------------------------------------------------------- >> >> >> - The opaque ID field descriptions in sections 2 and 3 read a >> little oddly to me. What happens if someone decides to use up >> ID=0? Does that mean they can't overwrite that value until >> much later maybe? > > Since it is only to provide uniqueness for opaque LSAs of the same type > originated by the same router, there is no consequence of using 0.
Well one cannot send a value less than zero though can you? Which means that you can't supercede the one that used zero I think. (It says the lowest value has precedence doesn't it?) > > >> And what if a whole bunch of routers choose >> the same value (because it's configured or hard-coded)? I >> think you need a bit more text on that. And with only 24 bits >> the probability of a collision if you just pick randomly isn't >> that low, so I'm not sure if random selection is a good plan >> here either. (How often will a new one of these be seen?) > > The scope of the Opaque ID is only the originating router so each has its > own number space. Where does it say that? Sorry if I missed it. > >> >> - Do these opaque values get forwarded widely? If so, then I >> guess they may provide a covert channel. I didn't see that >> mentioned in the security considerations of RFC5250. Is it >> mentioned elsewhere? If not, is it worth a mention here? >> (Probably not, but thought I'd ask.) > > Unlike unused protocol fields, it is not really covert since it is a part > of the OSPF LSA ID and is viewable in OSPF OAM and logs. Since it is just > a number, one could, however, set it arbitrarily. So that's a "no, no need to mention that" then is it? (Which is ok.) S. > > >> >> - Thanks for section 5. Nice to see. (Makes me wonder what >> those implementations do with the opaque ID though:-) > > The Opaque ID is just used as a key for LSAs. > > Thanks, > Acee > > >> >> > _______________________________________________ OSPF mailing list OSPF@ietf.org https://www.ietf.org/mailman/listinfo/ospf
