Re: [Lsr] draft-ietf-ospf-yang

["Acee Lindem (acee)" <[e-mail]>]

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" <[e-mail]> wrote:

    ----- Original Message -----
    From: <[e-mail]>
    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:[e-mail]]
    > Sent: Wednesday, December 05, 2018 12:14
    > To: Acee Lindem (acee); LITKOWSKI Stephane OBS/OINIS; [e-mail];
    [e-mail]; [e-mail]
    > 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)" <[e-mail]>
    > To: "tom petch" <[e-mail]>;
    <[e-mail]>;
    > <[e-mail]>; <[e-mail]>;
    > <[e-mail]>
    > Sent: Tuesday, December 04, 2018 7:46 PM
    >
    > > Hi Tom,
    > >
    > > Let me try to explain.
    > >
    > > On 12/4/18, 12:44 PM, "tom petch" <[e-mail]> 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
    > >
    > >
    > >
    > >
    >
    >
    >
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