Hi Tom, Please see inline ...
> -----Original Message----- > From: tom petch <[email protected]> > Sent: 13 April 2022 10:22 > To: Rob Wilton (rwilton) <[email protected]>; [email protected]; > [email protected] > Subject: Re: [netmod] [Lsr] I-D Action: draft-ietf-lsr-ospfv3-extended-lsa- > yang-10.txt > > From: netmod <[email protected]> on behalf of Rob Wilton > (rwilton) <[email protected]> > Sent: 11 April 2022 18:06 > > Hi all, > > Thanks for the comments on this thread so far. It would be nice if we are > able to come to some sort of rough consensus to a solution. > > I think that there is consensus that the YANG type ip-address (and the v4/v6 > versions) are badly named as the prominent default type name has been > given to the unusual variant of including zone information. > > Based on the comments on this thread, it also seems likely to me that most > of the usages of ip-address in YANG RFCs is likely to be wrong, and the > intention was that IP addresses without zones was intended. At a rough > count, of the published RFC YANG models at github > YangModels/standard/ietf/RFC/ to be: > 86 uses of ip-address > 68 uses of ipv4-address > 66 uses of ipv6-address > > 1 use of ip-address-no-zone > 4 uses of ipv4-address-no-zone > 4 uses of ipv6-address-no-zone > > These types appear in 49 out of the 141 YANG modules published in RFCs. At > a quick guess/check it looks like these 49 YANG modules may appear in 40-50 > RFCs. > > > <tp> > > As is sometimes the case with the processes of the IETF, this ignores any > issues of transition. I have pointed out a significant number of WG that have > modules in I-D which include no-zone, in various states, perhaps increasing > your figures by an order of magnitude. What are you going to do with I-D > e.g. in the RFC Editor queue? Haul them back? I think that depends on what consensus is reached. I have no desire of trying to republish existing RFCs to either change "ip-address" to "ip-address-no-zone" or to change "ip-address-no-zone" to "ip-address". I think the pragmatic thing to do would be to potentially flag these as errata so that they are hopefully fixed if/when the YANG module is eventually updated. Entirely separately from this specific discussion, it would be good if we (the IETF) could come up with a better long-term plan for maintaining and evolving IETF YANG modules. > > I think that the plan below is a bad one. I would introduce types with zone - > that is a no-brainer - but would deprecate the existing types. Why is deprecating an existing type a problem? It is deprecated, not obsolete. It does not mean that modules can't use "ip-address-no-zone", it would just indicate that "ip-address" is the recommended type, if we get to a consensus where ip-address should migrate to meaning exactly the same as ip-address-no-zone. There are APIs in Java that have been deprecated for 10+ years that are still available for use, but where the recommended is to not use them, or use a replacement API instead. Regards, Rob > > Tom Petch > > As mentioned previously, it is also worth comparing this to the OpenConfig > YANG modules: > They have redefined ip-address (and v4/v6 variants) to exclude zone > information and have defined separate types include zone information. > There are no explicit uses of the "-zoned" variants of OpenConfig IP > addresses in the latest OpenConfig github repository. However, > approximately a third of the IP address types are still to the ietf-inet- > types.yang rather than openconfig-inet-types.yang, so in theory some of > those 58 entries could still intentionally be supporting zoned IP addresses, > but I would expect that the vast majority would not. > I do see some strong benefit if this basic type being defined in the same way > in both IETF and OC YANG, and I believe that the OC folks have got the > definition right. > > I see that some are arguing that the zone in the ip-address definition is > effectively optional, and implementations are not really obliged to > implement it. I don't find that argument compelling, at least not with the > current definition of ip-address in RFC 6991. I see a clear difference > between > a type defined with an incomplete regex that may allow some invalid values > and a type that is explicitly defined to included additional values in the > allowable value space. Further, I believe that a client just looking at the > YANG module could reasonably expect a server that implements a data node > using ip-address would be expected to support IP zones, where they are > meaningful, or otherwise they should deviate that data node to indicate that > they don't conform to the model. > > We also need to be realistic as to what implementations will do. They are > not going to start writing code to support zones just because they are in the > model. They will mostly reject IP addresses with zone information. Perhaps > some will deviate the type to ip-address-no-zone, but probably most won't. > > The option of respinning approx. 40-50 RFCs to fix this doesn't feel at all > appealing. This would take a significant amount of time/effort and I think > that we will struggle to find folks who are willing to do this. Although > errata > could be used to point out the bug, then can't be used to fix it, all the > errata > would be "hold for document update" at best. Further, during the time that > it would take us to fix it, it is plausible that more incorrect usages of ip- > address will likely occur (but perhaps could be policed via scripted > checks/warnings). > > > I still feel the right long-term solution here is to get to a state where the > "ip- > address" type means what 99% of people expect it to mean, i.e., excluding > zone information. > > Given the pushback on making a single non-backwards compatible change to > the new definition, I want to ask whether the following might be a possible > path that gains wider consensus: > > (1) In RFC 6991 bis, I propose that we: > (i) define new ip-address-with-zone types (and v4 and v6 versions) and keep > the -no-zone versions. > (ii) we change the description of "ip-address" to indicate: > - Although the type allows for zone information, many implementations are > unlikely to accept zone information in most scenarios (i.e., so the > description > of the type more accurately reflects reality). > - A new ip-address-with-zone type has been introduced to use where zoned > IP addresses are required/useful, and models that use ip-address with the > intention of supporting zoned IP addresses MUST migrate to ip-address-with- > zone. > - In the future (at least 2 years after RFC 6991 bis is published), the > expectation is that the definition of ip-address will change to match that of > ip-address-no-zone. > > (2) Then in 2 years time, we publish RFC 6991-bis-bis to change the definition > of ip-address to match ip-address-no-zone and deprecate the "-no-zone" > version at the same time. > > My reasoning as to why to take this path is: > (1) It is a phased migration, nothing breaks, 3rd parties have time to > migrate. > (2) It ends up with the right definition (with the added bonus that it aligns > to > the OC definition). > (3) It doesn't require us republishing 40+ RFCs. > (4) it hopefully allows us to use YANG versioning to flag this as an NBC > change, along with the other standards to help mitigate this change (import > revision-or-derived, YANG packages, schema comparison). > > I would be keen to hear thoughts on whether this could be a workable > consensus solution - i.e., specifically, you would be able to live with it. > > Regards, > Rob > > > > > -----Original Message----- > > From: netmod <[email protected]> On Behalf Of Randy Presuhn > > Sent: 08 April 2022 18:59 > > To: Christian Hopps <[email protected]> > > Cc: [email protected]; [email protected] > > Subject: Re: [netmod] [Lsr] I-D Action: draft-ietf-lsr-ospfv3-extended-lsa- > > yang-10.txt > > > > Hi - > > > > On 2022-04-08 5:11 AM, Christian Hopps wrote: > > .. > > > Instead, Acee (I'm not sure I'd call him WG B :) is asserting that > > > *nobody* actually wanted the current type, and it has been misused > > > everywhere and all over. The vast majority of implementations in > > > operation probably can't even handle the actual type (Andy's point). So, > > > Acee is just the messenger of bad news here. Please note that the AD in > > > charge of all this agreed with Acee as well. > > > > That's not the impression one gets from modules like > > https://www.ietf.org/archive/id/draft-ietf-mpls-mldp-yang-10.txt > > which employs both types. So, regardless of whether one is willing > > to respect YANG's compatibility rules, it's no longer a matter of > > speculation whether a name change would cause actual damage - > > it clearly would. Furthermore, my recollection is that the > > WG *did* discuss whether the "zonable" property was needed, so > > any argument based on the assertion that "*nobody* actually > > wanted the current type" seems to me to based on a false premise. > > > > Randy > > > > _______________________________________________ > > netmod mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/netmod > > _______________________________________________ > netmod mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/netmod _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
