Chris/Acee -


I strongly agree with Peter.



There is no point in creating a protocol specific registry for behavior values 
which are protocol agnostic.

This only adds duplication (which is NOT the same as redundancy 😊 ).



What I find unfortunate is that the table in Section 10 of 
draft-ietf-lsr-isis-srv6-extensions-06.txt  has a "Behavior Endpoint Codepoint" 
column. That should be removed.

The legal behaviors to be advertised by IS-IS are then defined by name in 
column 1. If you want to find the numerical value(s) associated with that name 
then you refer to the registry created by 
draft-ietf-spring-srv6-network-programming.



   Les





> -----Original Message-----

> From: Lsr <[email protected]> On Behalf Of Christian Hopps

> Sent: Tuesday, March 10, 2020 4:51 AM

> To: Peter Psenak (ppsenak) <[email protected]>

> Cc: [email protected]; Christian Hopps <[email protected]>; Acee Lindem (acee)

> <[email protected]>; [email protected]; Peter Psenak

> <[email protected]>

> Subject: Re: [Lsr] "Legal" endpoint behaviors [draft-ietf-lsr-isis-srv6-

> extensions-06.txt]

>

>

> Peter Psenak <[email protected]<mailto:[email protected]>> writes:

>

> > Hi Acee,

> >

> > On 09/03/2020 14:49, Acee Lindem (acee) wrote:

> >> Hi Peter, Chris,

> >>

> >> I agree that a number of IS-IS IANA registries have this level of

> specification. For example:

> >>

> >> https://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv-<https://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv-codepoints.xhtml#isis-tlv-codepoints-22-23-25-141-222-223>

> codepoints.xhtml#isis-tlv-codepoints-22-23-25-141-222-223<https://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv-codepoints.xhtml#isis-tlv-codepoints-22-23-25-141-222-223>

> >

> > above is an ISIS specific registry and all external documents just updates

> this

> > protocol specific registry - e.g. the same link attribute defined in some

> > external document has different value in ISIS, OSPF, OSPFv3, etc.

> >

> > SRv6 SID behaviors are different, because they are not ISIS (protocol)

> specific

> > values - they apply to other protocols (OSPF, BGP-LS, ...). As such a 
> > protocol

> > independent registry defines them and each protocol just refers to it.

>

> The equivalent to these IS-IS sub-TLV registries would be to add "carried in

> IS-IS sub-TLV/OSPF-Sub-TLV/etc" columns to the SRv6 protocol-agnostic

> behavior registry. This does not seem the correct path to me as now you

> have various transport protocols adding columns to the protocol agnostic

> registry. Instead, I'm suggesting that we create protocol specific registries

> along-side the behavior value registry to document the protocol specific use,

> leaving a reference to these protocol registries in the behavior registry to 
> link

> them.

>

> Registries are non-normative, and you're not usurping or duplicating the role

> of the SRv6 behavior value registry by tracking additional protocol specific

> restrictions elsewhere by using one. Registries are there to help us keep

> track of stuff. In all the above cases (what goes where) it also helps make

> sure people *have* normatively documented *somewhere* all the cases

> they need to when adding new values/tvls.

>

> Do you think its better to modify the SRv6 registry directly and add protocol

> specific columns to it?

>

> Thanks,

> Chris.

> (as WG member)

>

> >

> > thanks,

> > Peter

> >

> >>

> >> Thanks,

> >> Acee

> >>

> >> On 3/9/20, 8:28 AM, "Lsr on behalf of Christian Hopps" 
> >> <lsr-<mailto:[email protected]%20on%20behalf%20of%[email protected]>

> [email protected] on behalf of 
> [email protected]<mailto:[email protected]%20on%20behalf%20of%[email protected]>>
>  wrote:

> >>

> >>                > On Mar 9, 2020, at 6:36 AM, Peter Psenak

> >> <[email protected]<mailto:[email protected]>>
> >>  wrote:

> >>      >

> >>      > Hi Chris,

> >>      >

> >>      > On 07/03/2020 15:46, Christian Hopps wrote:

> >>      >> 1) I think we should have an IANA registry instead of just a table

> defined in section 10 of draft-ietf-lsr-isis-srv6-extensions-06.

> >>      >> The registry could be cross-referenced by and to "SRv6 Endpoint

> Behaviors" for each protocol carrying these behaviors (IS-IS, OSPFv3, ...).

> If/when new behaviors are added they could then update where they are

> supposed to be advertised in the underlying protocols.

> >>      >

> >>      > why do we need a protocol specific registry to advertise values that

> are defined in another protocol independent registry? I have never seen

> such a duplication. Looks completely redundant to me.

> >>           You are creating some new sub TLVs (End, End.X, LAN End.X), and

> you

> >> are restricting and directing which externally defined behaviors (values)

> can

> >> be advertised in which of these TLVs. The registry would keep track of this

> >> (e.g., "Valid behaviors for sub-TLVs End, End.X, LAN End.X")

> >>           What happens when new behaviors are defined (externally), which

> TLVs

> >> are they supposed to be advertised in? Either the document that defines

> the

> >> new behavior or a related LSR document will have to indicate where this

> new

> >> behavior should be advertised too. That new document would update

> this

> >> registry to track that. Keeping track of this stuff is what registries are

> >> for.

> >>           Your table literally looks like a template for the initial 
> >> content

> >> of a registry. :)

> >>           Later in your IANA section you are updating other registries that

> >> bear a striking resemblance to this (e.g., what sub-TLV types are valid to

> >> advertise in what TLVs).

> >>           >> 2) It's odd that we are referring to the section as "Legal

> >> Behaviors" in the TLV definitions, and then in the actual section using

> "MAY"

> >> terms and no "MUST"/"MUST NOT", but then using "Yes" and "No" in the

> table.

> >>      >

> >>      > a) Legal Behavior - refers to the set of values defined in the 
> >> [I-D.ietf-

> spring-srv6-network-programming] which can be advertised in a particular

> TLV

> >>      >

> >>      > b) We can not use MUST in section 10, as all these TLVs are optional

> >>           What's wrong with "If this behavior is advertised it MUST only be

> >> advertised in the TLV[s] as indicated by "Y" in the table below, and MUST

> NOT

> >> be advertised in the TLV[s] as indicated by "N" in the table below." or

> >> something like that.

> >>           Thanks,

> >>      Chris.

> >>      (as WG member)

> >>                > c) Yes/No means whether the particular behavior is 
> >> allowed in

> >> the particular END-SID TLV.

> >>      >

> >>      >> Are these suggestions or are they documenting the required

> behavior?

> >>      >

> >>      > these are limitations as to which behavior is allowed to be 
> >> advertised

> in which TLV.

> >>      > thanks,

> >>      > Peter

> >>      >

> >>      >> Thanks,

> >>      >> Chris.

> >>      >

> >>      > _______________________________________________

> >>      > Lsr mailing list

> >>      > [email protected]<mailto:[email protected]>

> >>      > https://www.ietf.org/mailman/listinfo/lsr

> >>      >

> >>           _______________________________________________

> >>      Lsr mailing list

> >>      [email protected]<mailto:[email protected]>

> >>      https://www.ietf.org/mailman/listinfo/lsr

> >>

> >>

> >>

> >>


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