Re: [bess] [mpls] [Idr] Fwd: Working Group adoption poll on draft-rosen-mpls-rfc3107bis

[Robert Raszuk]

​Acee,​


> The current capability is specific to support of multiple labels - not
> your parochial view on the interaction between SAFIs.
>

​Since "bis" specification obsoletes the base document I was under the
assumption that new capability will also obsolete the current used.

It is no longer "3107bis" but just a new draft or at best errata -  to the
best of my understanding of IETF rules "bis" obsoletes the original spec.
Requiring implmentors to read and follow both specifications to correctly
implement the labeled BGP AF seems a bit odd ... don't you think ?

 Are you suggesting a second capability? All the more reason for a separate
> draft.
>

​No.​ See above.

In any event, the non-backward compatible behavior you are proposing would
> be better served in a separate draft than to burden RFC 3107 BIS.
>

​Section 5 already discusses that point - so my comment should be
considered as feedback towards that section . If there is WG consensus to
proceed with that it would be pure waist of time to write a separate draft
to argue against it.

It seems interesting that IETF WG feedback expressed on the list for
specific section of the draft in adoption call or during WG progress is
turned around and request is made to write a new draft instead.

Especially that document wise the feedback consideration may require
addition of two sentences within section 5 :).

Cheers,
R.
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Re: [bess] [mpls] [Idr] Fwd: Working Group adoption poll on draft-rosen-mpls-rfc3107bis

[Acee Lindem (acee)]

Hi Robert,

From: > on behalf of Robert Raszuk 
>
Date: Wednesday, August 31, 2016 at 10:40 AM
To: Acee Lindem >
Cc: Eric C Rosen >, IDR List 
>, "m...@ietf.org" 
>, "bess@ietf.org" 
>
Subject: Re: [mpls] [Idr] Fwd: Working Group adoption poll on 
draft-rosen-mpls-rfc3107bis

Hi Acee,

There is no issue for compatibility as new proposal has its new BGP capability 
hence there is no issue with deploying it gradually.

The current capability is specific to support of multiple labels - not your 
parochial view on the interaction between SAFIs. Are you suggesting a second 
capability? All the more reason for a separate draft.


Yes it requires new RIB work for those implementations which today use single 
RIB for both SAFI 1 and SAFI 4. FIB and LFIB are already separate. Each SAFI in 
BGP also normally has it's own separate tables. So if anything it requires a 
bit of cleanup work.

So you are saying SAFI 4 would only apply to ILM and not NHLFE when the same 
prefix is advertised in both SAFI 1 and SAFI 4? Maybe I am missing something 
but I don’t see that this is useful deployment. In any event, the non-backward 
compatible behavior you are proposing would be better served in a separate 
draft than to burden RFC 3107 BIS.


Main motivation here would be to help new vendors to make the unified choice in 
how they will implement 3107bis so long term we get some consistent way SAFI 4 
is delivered. And if now at the "bis" rfc is not a good time then what you are 
really advocating is to stay for years to come with such undefined randomness 
across implementations.

I agree with the current draft that it should be local policy. I don’t think 
you can assume that everyone agrees that this should be specified and that your 
view on how it should work is consensus. Hence, put it in a separate draft.


Other then consistency I also see folks trying to use labeled BGP as controller 
to network device protocol to install labels. For that use case alone complete 
separation from SAFI 1 is very helpful.

You have both ILM and NHLFE to consider here. I look forward to reviewing your 
draft on this topic. If there is consensus, merger with the draft under WG 
adoption can be considered.

Thanks,
Acee




Thx,
R.



On Wed, Aug 31, 2016 at 4:15 PM, Acee Lindem (acee) 
> wrote:
Hi Robert,

Currently, everything in draft-rosen-mpls-rfc3107bis is pretty much backward 
compatible with our more than a decade old RFC 3107 implementations and 
deployments. What you are proposing is not and has implications in both the 
control and forwarding planes. If you really believe that this is “the biggest 
issue", I’d suggest you articulate it in a separate draft with concrete use 
cases for having separate IP and MPLS topologies for the same set of prefixes. 
Then the WGs can evaluate the requirement and proposed solution independent of 
RFC 3107 BIS.

Thanks,
Acee

From: mpls > on behalf of 
Robert Raszuk >
Date: Wednesday, August 31, 2016 at 5:24 AM
To: Eric C Rosen >
Cc: IDR List >, 
"m...@ietf.org" >, 
"bess@ietf.org" >
Subject: Re: [mpls] [Idr] Fwd: Working Group adoption poll on 
draft-rosen-mpls-rfc3107bis

Hi Eric,

While adoption call is sort of encouragement for further input before I respond 
to Loa's mail I would like to get one additional answer from 3107bis authors 
and WGs members.

Those who spend years in mpls deployment know quite well that the biggest issue 
with today's 3107 deployment is lack of the clear definition of its interaction 
with SAFI-1. While one would hope that 3107bis with new capability will clean 
this mess section 5 of your document rather sweeps it all under the carpet 
stating that it is just local policy. IMO it is not a matter of local policy 
nor it is implementation detail.

Local policy can be to choose which RIB (or sequence of RIBs) should be used 
for resolution of specific SAFIs and not how to mix SAFI-1 with SAFI-4. It's 
not a local matter at all to have deployment resulting in inconsistent IBGP 
best paths across given domain.

To me cleanest is to separate those two SAFIs completely from each other by the 
spec both in BGP (done) as well as local RIB and FIB/LFIB.

Likewise I do not quite agree that SAFI-4 should be "convertible" to SAFI-1. 
And we all realize that opposite direction is rather hard.

Another perhaps minor clarification would 

Re: [bess] [mpls] [Idr] Fwd: Working Group adoption poll on draft-rosen-mpls-rfc3107bis

[Robert Raszuk]

Hi Acee,

There is no issue for compatibility as new proposal has its new BGP
capability hence there is no issue with deploying it gradually.

Yes it requires new RIB work for those implementations which today use
single RIB for both SAFI 1 and SAFI 4. FIB and LFIB are already separate.
Each SAFI in BGP also normally has it's own separate tables. So if anything
it requires a bit of cleanup work.

Main motivation here would be to help new vendors to make the unified
choice in how they will implement 3107bis so long term we get some
consistent way SAFI 4 is delivered. And if now at the "bis" rfc is not a
good time then what you are really advocating is to stay for years to come
with such undefined randomness across implementations.

Other then consistency I also see folks trying to use labeled BGP as
controller to network device protocol to install labels. For that use case
alone complete separation from SAFI 1 is very helpful.

Thx,
R.



On Wed, Aug 31, 2016 at 4:15 PM, Acee Lindem (acee)  wrote:

> Hi Robert,
>
> Currently, everything in draft-rosen-mpls-rfc3107bis is pretty much
> backward compatible with our more than a decade old RFC 3107
> implementations and deployments. What you are proposing is not and has
> implications in both the control and forwarding planes. If you really
> believe that this is “the biggest issue", I’d suggest you articulate it in
> a separate draft with concrete use cases for having separate IP and MPLS
> topologies for the same set of prefixes. Then the WGs can evaluate the
> requirement and proposed solution independent of RFC 3107 BIS.
>
> Thanks,
> Acee
>
> From: mpls  on behalf of Robert Raszuk <
> rob...@raszuk.net>
> Date: Wednesday, August 31, 2016 at 5:24 AM
> To: Eric C Rosen 
> Cc: IDR List , "m...@ietf.org" , "
> bess@ietf.org" 
> Subject: Re: [mpls] [Idr] Fwd: Working Group adoption poll on
> draft-rosen-mpls-rfc3107bis
>
> Hi Eric,
>
> While adoption call is sort of encouragement for further input before I
> respond to Loa's mail I would like to get one additional answer from
> 3107bis authors and WGs members.
>
> Those who spend years in mpls deployment know quite well that the biggest
> issue with today's 3107 deployment is lack of the clear definition of its
> interaction with SAFI-1. While one would hope that 3107bis with new
> capability will clean this mess section 5 of your document rather sweeps it
> all under the carpet stating that it is just local policy. IMO it is not a
> matter of local policy nor it is implementation detail.
>
> Local policy can be to choose which RIB (or sequence of RIBs) should be
> used for resolution of specific SAFIs and not how to mix SAFI-1 with
> SAFI-4. It's not a local matter at all to have deployment resulting in
> inconsistent IBGP best paths across given domain.
>
> To me cleanest is to separate those two SAFIs completely from each other
> by the spec both in BGP (done) as well as local RIB and FIB/LFIB.
>
> Likewise I do not quite agree that SAFI-4 should be "convertible" to
> SAFI-1. And we all realize that opposite direction is rather hard.
>
> Another perhaps minor clarification would be to get an explicit
> confirmation that SAFI-4 can be recursive over SAFI-4 or for that matter
> SAFI-1 (MPLS in GRE or SR in IP).
>
> Thx,
> R.
>
>
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Re: [bess] [mpls] [Idr] Fwd: Working Group adoption poll on draft-rosen-mpls-rfc3107bis

[Acee Lindem (acee)]

Hi Robert,

Currently, everything in draft-rosen-mpls-rfc3107bis is pretty much backward 
compatible with our more than a decade old RFC 3107 implementations and 
deployments. What you are proposing is not and has implications in both the 
control and forwarding planes. If you really believe that this is “the biggest 
issue", I’d suggest you articulate it in a separate draft with concrete use 
cases for having separate IP and MPLS topologies for the same set of prefixes. 
Then the WGs can evaluate the requirement and proposed solution independent of 
RFC 3107 BIS.

Thanks,
Acee

From: mpls > on behalf of 
Robert Raszuk >
Date: Wednesday, August 31, 2016 at 5:24 AM
To: Eric C Rosen >
Cc: IDR List >, 
"m...@ietf.org" >, 
"bess@ietf.org" >
Subject: Re: [mpls] [Idr] Fwd: Working Group adoption poll on 
draft-rosen-mpls-rfc3107bis

Hi Eric,

While adoption call is sort of encouragement for further input before I respond 
to Loa's mail I would like to get one additional answer from 3107bis authors 
and WGs members.

Those who spend years in mpls deployment know quite well that the biggest issue 
with today's 3107 deployment is lack of the clear definition of its interaction 
with SAFI-1. While one would hope that 3107bis with new capability will clean 
this mess section 5 of your document rather sweeps it all under the carpet 
stating that it is just local policy. IMO it is not a matter of local policy 
nor it is implementation detail.

Local policy can be to choose which RIB (or sequence of RIBs) should be used 
for resolution of specific SAFIs and not how to mix SAFI-1 with SAFI-4. It's 
not a local matter at all to have deployment resulting in inconsistent IBGP 
best paths across given domain.

To me cleanest is to separate those two SAFIs completely from each other by the 
spec both in BGP (done) as well as local RIB and FIB/LFIB.

Likewise I do not quite agree that SAFI-4 should be "convertible" to SAFI-1. 
And we all realize that opposite direction is rather hard.

Another perhaps minor clarification would be to get an explicit confirmation 
that SAFI-4 can be recursive over SAFI-4 or for that matter SAFI-1 (MPLS in GRE 
or SR in IP).

Thx,
R.

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