Hi Andy, thanks for responding so promptly. A few comments in line:
On 2010-12-18 18:36, Andy Kessler (kessler) wrote: > Hi, > > Thank you for the review. > My comments are below annotated with Andy> > > Andy > > > I am the assigned Gen-ART reviewer for this draft. For background on > Gen-ART, please see the FAQ at > <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. > > Please resolve these comments along with any other Last Call comments > you may receive. > > Document: draft-ietf-pim-group-rp-mapping-07.txt > Reviewer: Brian Carpenter > Review Date: 2010-12-18 > IETF LC End Date: 2010-12-23 > IESG Telechat date: > > Summary: In good shape, a few issues. > -------- > > Major issues: > ------------- > > 3. Existing algorithm > ... > The algorithm defined in this document updates algorithm defined in > PIM-SM ( Section 4.7.1 in [RFC4601]). The new algorithm is backward > compatible and will produce the same result only if the Group-to-RP > mappings are learned from a single mapping source. > > A logical implication of the last sentence is that if some of the Group-to-RP > mappings are learned from more than one mapping source, the new algorithm > might > not produce the same result as the existing algorithm. Is that indeed the > case, > and if so, don't we have a problem until all PIM-SM routers have been updated? > > Andy> Most vendors today do not officially support deployments with multiple > Andy> dynamic routing protocols. They probably have inconsistent results now. > Andy> This algorithm will standardize the results for those vendors. It will > Andy> be more consistent when all vendors do support the new algorithm. OK. Maybe you could add a sentence to make it clear that adding the new algorithm doesn't fix the problem completely until it's universally deployed. > 5. Common use cases > > o Default static Group-to-RP mappings with dynamically learned > entries > > Many network operators will have a dedicated infrastructure for the > standard multicast group range (224/4) and so might be using > statically configured Group-to-RP mappings for this range. > > Please indicate whether this issue also applies to IPv6. > > Andy> There is no issue with IPv6. IPv4 has some older baggage because > Andy> the 224/4 addressing scheme has been around since before there was > Andy> SSM and BSR. IPv6 Multicast does not have that history. OK. For someone ignorant of the history, it might be worth adding "This issue does not arise for IPv6." > > > > 6. Proposed algorithm > ... > 10. From the remaining set of Group-to-RP Mappings we will select > the RP with the highest IP address. This will serve as a final > tiebreaker. > > Please define "highest". Does it mean "greatest when considered as an > unsigned integer"? > > Andy> This should be the same method that is used to pick > Andy> the highest IP address in many protocols. One I know well is > Andy> the way that a designated router is selected in RFC 4601 in > Andy> section 4.3.2. The main part of the function says: > Andy> a.primary_ip_address > b.primary_ip_address > Andy> To me that has always meant you compare the first byte, > Andy> then the 2nd, the 3rd and then the 4th. and the 5th, etc, for IPv6 ;-) > Andy> I don't know where that would be defined. Maybe someone else knows. > Andy> It is not defined in RFC 4601. I have no idea either. Maybe it's a term of art in routing protocols, so I won't insist; I was just looking at it from the viewpoint of a naive implementor. > 8. Clarification for MIB Objects > > When a Group-to-RP mapping entry is created in the > pimGroupMappingTable in the PIM-STD MIB[RFC5060], it would be > acceptable to have an entry with an RP with address type 'unknown' > and a PimMode of Dense Mode or SSM. These entries would represent > group ranges for Dense mode or SSM. > > Also all the entries which are already included in the SSM Range > table in the IP Mcast MIB would be copied over to > pimGroupMappingTable. They would have a type of configSSM and an RP > with address type 'unknown' as described above. > > Is this section intended to be a normative update of RFC 5060, or is > it just commentary? The phrase "it would be acceptable" almost sounds > like a normative MAY. > > Also, shouldn't it be 'unknown(0)' in the context of the MIB? (This > applies in three places in the draft.) > > Andy> At some point we received comments and requests to include all > Andy> the group mappings in this table - even for Dense Mode or SSM > Andy> which do not have an RP. We are merely stating that it OK to > Andy> do that and use the RP address and type (of the RP) of unknown. > Yes, it makes sense, but please make it very clear whether you are writing normatively or not. > > Nits: > ----- > > 5. Common use cases > ... > o More use cases > > By no means, the above list is complete. Please drop a mail to > 'authors' if you see any other use case for this. > > This seems a bit strange to appear in the final RFC; at the least it needs > rewriting. > > Andy> I agree. That was for the draft and should be removed. Should we > Andy> just remove the whole section ? Or change the wording to somehow > Andy> say there are more use cases that will benefit from this algorithm ? Either way is fine for me. > > The checker says: > > == There are 1 instance of lines with multicast IPv4 addresses in the > document. If these are generic example addresses, they should be changed > to use the 233.252.0.x range defined in RFC 5771 > > Andy> We have discussed this before. We need to use the addresses that in the > Andy> examples. 239/8 is the Administratively Scoped Block as defined in RFC > 5771. > Andy> Its the same thing for 239.100.0.0/16 in section 5. We were told to add > Andy> the comment that says its an administratively scoped multicast address > Andy> range. Using GLOP will not make the same point we are trying to > explain. Fair enough. Don't be surprised if someone in the IESG asks the same question. Brian _______________________________________________ Gen-art mailing list [email protected] https://www.ietf.org/mailman/listinfo/gen-art
