----- Original Message ----- From: "Xufeng Liu" <xufeng.liu.i...@gmail.com> Sent: Wednesday, December 12, 2018 4:25 AM Subject: Re: draft-ietf-ospf-yang
On Tue, Dec 11, 2018 at 7:25 AM tom petch <ie...@btconnect.com> wrote: > ----- Original Message ----- > From: "Xufeng Liu" <xufeng.liu.i...@gmail.com> > Sent: Monday, December 10, 2018 2:47 PM > > Hi Tom, > > Thanks for checking on this. Agree that we need to fix the description > text. What about the following? > > te-node-id: > A type representing the identifier for a node in a TE topology. > The > identifier is represented as 32-bit unsigned integer in the dotted-quad > notation. This attribute MAY be mapped to the Router Address described > in > Section 2.4.1 of [RFC3630], the TE Router ID described in Section 3 of > [RFC6827], the Traffic Engineering Router ID described in Section 4.3 of > [RFC5305], or the TE Router ID described in Section 3.2.1 of [RFC6119]. > The > reachability of such a TE node MAY be achieved by a mechanism such as > Section 6.2 of [RFC6827]. > > Or, would you give a suggestion? > > <tp> > > Looks good. > > One query I cannot answer; should > RFC5786 Advertising a Router's Local Addresses in OSPF > TE Extensions. R. Aggarwal, K. Kompella. March 2010 > be there as well? On the face of it, it looks relevant and would appear > to meet a need but I note its absence from ospf-yang; I do not know how > widely it is implemented or used. This RFC is updated by RFC6827. RFC6827 uses RFC5786, making it more generic and more complete, I think. As you said, RFC6827 has updated RFC5786, which is cited heavily in RFC6827. So, logically RFC5786 is already covered. Since RFC5786 does not provide a TE Router ID mapping by itself, I could not figure out a concise wording to cite it separately, so I felt that RFC6827 would be more relevant. Any suggestion would be appreciated. <tp> On reflection, leave it as it is; the text in RFC6827 is, overall, clearer than RFC5786. On an unrelated topic, te-types has references in the YANG module to RFC7823 - good - but this RFC does not appear in the References for the ID - not so good. Having added it, you will need a reference to it in the text of the I-D lest you get an unused reference. Common practice is to have a section preceding the module along the lines of "This module imports [ ..] and references [....]. 3.1 has the imports but not the references. And it is expected to have references for imports, e.g. import ietf-inet-types { prefix "inet"; reference "RFC 6991 - Common YANG Data Types"; Tom Petch Thanks, - Xufeng > > Tom Petch > > Thanks, > - Xufeng > > On Fri, Dec 7, 2018 at 12:14 PM tom petch <ie...@btconnect.com> wrote: > > > ----- Original Message ----- > > From: "Xufeng Liu" <xufeng.liu.i...@gmail.com> > > Subject: Re: draft-ietf-ospf-yang > > > > > > Hi Acee, Tom, and All, > > > > Several authors of draft-ietf-teas-yang-te-types had a brief > discussion > > on > > this topic. Our take on the te-node-id and te-router-id is: > > > > - In TEAS, the te-node-id specified in draft-ietf-teas-yang-te-types > has > > a > > wider use scope than IP MPLS TE. The system may or may not run OSPF > TE, > > and > > may not use IPv4. The 32-bit ID number is used only for uniquely > > identifying the TE node, and it may or may not be a routable address. > > - When RFC3630 is implemented, it is ok to map a routable IPv4 address > > (such as the address of loopbak0) to the te-node-id, but it is not > > required. > > - We intentionally use the term "te-node-id" instead of "te-router-id" > > to > > convey the concept that this ID is on a TE node, which may or may or > be > > a > > router. > > - We will clarify the description to say that "This attribute is MAY > be > > mapped to TE Router ID in [RFC3630], [RFC5329], [RFC5305], and > > [RFC6119]." > > > > <tp> > > > > Xufeng > > > > Thanks for the clarification - I understand better now. > > > > However, I think that your proposed text is not quite right. RFC5329 > > does not defined a TE Router ID - in fact, I think that that concept > is > > alien to OSPF. OSPF has a 32 bit number that is the Router ID with no > > requirement for that to be a routable address; which is why (IMHO) > > RFC5329 defines a > > Router IPv6 Address TLV > > which carries a routable address (which can meet the needs of TE). > > > > Likewise, RFC3630, for OSPFv2, does not have the concept of a TE > Router > > ID; rather, it has a > > Router Address TLV > > which specifies a stable IP address (which can meet the needs of TE). > > > > And then there is RFC5786 which defines, for OSPF, the > > Node Attribute TLV > > with sub-TLV for > > Node IPv4 Local Address > > Node IPv6 Local Address > > allowing for multiple TE addresses for different traffic types. > > > > I grant you that RFC6119 defines a > > TE Router ID > > but the concept is alien to OSPF (IMHO). > > > > So, if you want to use the term > > TE Router ID > > then I think that you will need to explain how that maps onto the > > terminology of the existing OSPF RFC. > > > > Tom Petch > > > > Thanks, > > - Xufeng > > > > On Thu, Dec 6, 2018 at 12:38 PM Acee Lindem (acee) <a...@cisco.com> > > wrote: > > > > > Hi Tom, > > > I think the only action here is for the authors of > > > draft-ietf-teas-yang-te-types to fix their te-node-id definition. As > > for > > > the OSPF Router ID and OSPF/ISIS TE Router IDs we can't change the > > decades > > > old definitions to achieve uniformity. > > > Thanks, > > > Acee > > > > > > On 12/5/18, 11:12 AM, "tom petch" <ie...@btconnect.com> wrote: > > > > > > ----- Original Message ----- > > > From: <stephane.litkow...@orange.com> > > > Sent: Wednesday, December 05, 2018 12:57 PM > > > > > > > Hi Tom, > > > > > > > > I think that having a different router-id configured per > > protocol is > > > a > > > matter of deployment. I don't think that we can impose anything > in > > this > > > area. There are use cases where it is good to have separate > > router-ids > > > per protocol or instances of a protocol. For instance, when a > > router is > > > part of multiple "administrative domains", it is worth having > > separate > > > router-ids per admin domain. > > > > > > > > However I have a concern about the router-id or te-node-id > > bound to > > > a > > > 32 bits number only. How do we do in a pure IPv6 network ? > > > > > > Stephane > > > > > > I am used to configuring a router-id as a 32-bit number with no > > > requirement for that to be an address that can be accessed over > > the > > > internet (so I have always found the idea of 'loopback0' > > unfortunate). > > > Yes, the router needs to be addressable, but merging that > concept > > with > > > a > > > router id has always seemed to me unfortunate because they are > two > > > separate concepts. (In fact, I would regard good practice as > > giving a > > > router multiple addresses for different functions, so that e.g. > > syslog > > > can be separated from SNMP or FTP). > > > > > > Thus I have no problem with a 32-bit router-id in an IPv6 > network. > > > Indeed, RFC5329 defines a 32-bit router-id in an OSPFv3 > > > Intra-Area-TE-LSA. It is the Router IPv6 Address TLV that > carries > > the > > > 128-bit address. > > > > > > When ospf-yang says > > > container te-rid { > > > if-feature te-rid; > > > description "Stable OSPF Router IP Address used for > > Traffic > > > Engineering (TE)"; > > > leaf ipv4-router-id { type inet:ipv4-address; > > description > > > "Explicitly configure the TE IPv4 Router ID."; > > > } > > > leaf ipv6-router-id { > > > type inet:ipv6-address; > > > description "Explicitly configure the TE IPv6 > Router > > ID."; > > > > > > then that is when I wonder what is going on. That looks to me > > like > > > configuring > > > Router IPv6 Address TLV > > > not the router id. > > > > > > Meanwhile, te-yang-te-types has > > > > > > te-node-id: > > > A type representing the identifier for a node in a > topology. > > The > > > identifier is represented as 32-bit unsigned integer in > the > > > dotted-quad notation. This attribute is mapped to Router > ID > > in > > > [RFC3630], [RFC5329], [RFC5305], and [RFC6119]. > > > > > > Well, I disagree with their choice of YANG type but agree that > it > > is > > > 32-bit and not 128. > > > > > > Tom Petch. > > > > > > > Brgds, > > > > > > > > > > > > -----Original Message----- > > > > From: tom petch [mailto:ie...@btconnect.com] > > > > Sent: Wednesday, December 05, 2018 12:14 > > > > To: Acee Lindem (acee); LITKOWSKI Stephane OBS/OINIS; > > lsr@ietf.org; > > > draft-ietf-ospf-y...@ietf.org; > > draft-ietf-teas-yang-te-ty...@ietf.org > > > > Subject: Re: draft-ietf-ospf-yang > > > > > > > > Acee > > > > > > > > (Top-posting because the indentation usually fails) > > > > > > > > On the TEAS te-types, I had a quick look at where > > > > typedef te-node-id > > > > is used and the answer is lots of places, because it is part > of > > > > grouping explicit-route-hop { > > > > description "The explicit route subobject grouping"; > > > > choice type { > > > > description "The explicit route subobject type"; > > > > case num-unnum-hop { > > > > container num-unnum-hop { > > > > leaf node-id { > > > > type te-types:te-node-id; > > > > description "The identifier of a node in the TE > > > > topology."; > > > > and YANG uses of that grouping are many, in several WGs; > > however, > > > > because it is a grouping, then the impact of changing the type > > should > > > be > > > > minimal at least in terms of the I-Ds. > > > > > > > > On the multiple router definitions, my research of the IETF > memo > > only > > > > came up with the two cited RFC which, to me, say that you > should > > use > > > an > > > > existing router-id if there is one. > > > > > > > > I did look at the documentation of A Major Router Manufacturer > > and > > > while > > > > they did not give any advice, the default for a te router-id > was > > > > loopback0 > > > > while the default for a more general router-id, one without > te, > > was > > > > loopback0 > > > > which gives me the message, you can make them different but > > SHOULD > > > NOT > > > > (in IETF terminology). > > > > > > > > So while I agree that the two lsr modules should allow > > per-protocol > > > > configuration, I think that it should carry a health warning > in > > the > > > body > > > > of the I-D that this is not a good idea (I struggle to think > of > > when > > > it > > > > would be a good idea, to use three separate identifiers for, > > say, BGP > > > > and the two lsr protocols). > > > > > > > > Tom Petch > > > > > > > > ----- Original Message ----- > > > > From: "Acee Lindem (acee)" <a...@cisco.com> > > > > To: "tom petch" <ie...@btconnect.com>; > > > <stephane.litkow...@orange.com>; > > > > <lsr@ietf.org>; <draft-ietf-ospf-y...@ietf.org>; > > > > <draft-ietf-teas-yang-te-ty...@ietf.org> > > > > Sent: Tuesday, December 04, 2018 7:46 PM > > > > > > > > > Hi Tom, > > > > > > > > > > Let me try to explain. > > > > > > > > > > On 12/4/18, 12:44 PM, "tom petch" <ie...@btconnect.com> > wrote: > > > > > > > > > > The router id in this I-D confuse me. > > > > > > > > > > RFC8294 defines > > > > > typedef router-id { type yang:dotted-quad; > > > > > > > > > > Some implementations configure a global router-id while > others > > only > > > > allow it at the control-plane-protocol level. This is why we > > have it > > > in > > > > both places. > > > > > > > > > > ospf-yang defines > > > > > leaf ipv4-router-id { type inet:ipv4-address; > > > > > > > > > > For better or worse, OSPF has a separate TE address that is > > > routable > > > > and referred to as the TE router-id. You'll note that this is > > part of > > > > the te-rid container in both the OSPF and IS-IS YANG models. > We > > could > > > > add "-te-" to the leaves to avoid confusion. > > > > > > > > > > draft-ietf-teas-yang-te-types defines > > > > > typedef te-node-id { type yang:dotted-quad; > > > > > ... This attribute is mapped to Router ID .... > > > > > > > > > > This is just wrong. It is a routable address in the IGP TE > > > extensions. > > > > I've copied the draft authors. > > > > > > > > > > Thanks, > > > > > Acee Lindem > > > > > > > > > > > > > > > Three different YANG types for a router id. > > > > > > > > > > Why? > > > > > > > > > > Behind this, ospf-yang gives as references for a router > te > > id > > > > > RFC3630(V2) and RFC5329(V3). Reading these, my take is > > that a > > > > router id > > > > > is needed for te but that the existing id should be used > > where > > > > possible > > > > > i.e. creating an additional identifier for the same > > instance of > > > > the same > > > > > entity is A Bad Thing (which sounds like a good general > > > > principle). > > > > > With two objects in the lsr protocols, that would appear > > to > > > make > > > > at > > > > > least three identifiers for the same instance of the > same > > > entity. > > > > > > > > > > Why? > > > > > > > > > > I copy Stephane on this since the same issues apply to > the > > > other > > > > lsr > > > > > protocol, mutatis mutandi. > > > > > > > > > > Tom Petch > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ________________________________________________________________________ > > > _________________________________________________ > > > > > > > > Ce message et ses pieces jointes peuvent contenir des > > informations > > > confidentielles ou privilegiees et ne doivent donc > > > > pas etre diffuses, exploites ou copies sans autorisation. 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