Re: [Isis-wg] WG adoption of draft-baker-ipv6-isis-dst-src-routing-06

David Lamparter <> Fri, 09 December 2016 11:08 UTC

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Date: Fri, 09 Dec 2016 12:03:12 +0100
From: David Lamparter <>
To: "Les Ginsberg (ginsberg)" <>
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Subject: Re: [Isis-wg] WG adoption of draft-baker-ipv6-isis-dst-src-routing-06
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to give a more direct answer - yes, I think there will be devices
running IS-IS with dst-src routing.  It'll be more rare than OSPF, but
my subjective impression is that it'll still be significant.

I'm basing my subjective impression on 2 factors:

- Enterprise networks aren't always homogenous large blobs;  there's
  things like smaller branch offices that aren't integrated well and
  such.  It's reasonable to expect they might be running IS-IS as a
  "grand policy", yet run some branches on "pa-multihoming" setups.

- Choice of IS-IS vs. OSPF is for operators I know not quite related to
  target scope or size, but actually to "who started the setup".  If the
  person you hire to scale up your network likes IS-IS, they'll just
  deploy that and you're running it for the next 10 years.

  (Assuming their chosen vendor doesn't charge a larger license to
  enable IS-IS, which many unfortunately do.)

These two boil down to "dst-src is not unreasonable in a large
enterprise network" and "IS-IS is not solely a large-enterprise routing

Apart from that, while I don't want to take this assumption, I believe
dst-src has applications outside BCP38 exit routing, e.g. in separating
voice traffic for QoS, and in pushing security differentiations /

I still agree that dst-src setups are an order of magnitude more likely
to use OSPF, and OSPF is an order of magnitude more likely to see
dst-src deployments; but I believe there is enough dst-src IS-IS use
case to proceed here.


P.S.: The more interesting question is who else will be implementing
this.  That's where I see the larger potential for this draft to die
off -- but I'd like to make that evaluation at WGLC, not adoption ;)

(And I have heard of at least two large vendors looking at the topic.)

On Thu, Dec 08, 2016 at 09:40:25PM +0000, Les Ginsberg (ginsberg) wrote:
> Alia –
> I am aware of the RTGWG work – I am asking do we have reason to believe that there will be devices running IS-IS that require this support.
> If you have some information on this I would be interested to see it.
>    Les
> From: Alia Atlas []
> Sent: Thursday, December 08, 2016 12:40 PM
> To: Les Ginsberg (ginsberg)
> Cc: Tony Przygienda; Christian Hopps;;
> Subject: Re: [Isis-wg] WG adoption of draft-baker-ipv6-isis-dst-src-routing-06
> Les,
> On Thu, Dec 8, 2016 at 3:35 PM, Les Ginsberg (ginsberg) <<>> wrote:
> I think the bigger question – from the standpoint of WG adoption – is do we really believe there is a need for this extension?
> There was a time when IS-IS was being considered as the homenet protocol – that ship seems to have sailed.
> So the question becomes do we really think there is a deployment where these extensions will be needed? If the answer to that is yes, then I am convinced that the direction this draft has taken is the right one and we should then do the diligence necessary to finish the job.
> But if the answer is “no” then this does not seem a worthwhile use of our time.
> Have you been following the discussion in RTGWG around
> and<>  ?
> The issues around IPv6 multihoming are not primarily related to homenet - though homenet also has those same issues.
> Regards,
> Alia
> David (and/or others) – can you comment on this?
>    Les
> From: Isis-wg [<>] On Behalf Of Tony Przygienda
> Sent: Thursday, December 08, 2016 11:25 AM
> To: Christian Hopps
> Cc:<>;<>
> Subject: Re: [Isis-wg] WG adoption of draft-baker-ipv6-isis-dst-src-routing-06
> I sent good amount of comments on the draft a while ago. While I support adoption I think those need addressing to ensure correctness of the draft ... tony
> On Thu, Nov 10, 2016 at 6:27 AM, <<>> wrote:
> Hi Folks,
> The authors of draft-baker-ipv6-isis-dst-src-routing-06 have requested
> WG adoption. Please indicate whether you support adoption of this work
> (some folks already have on the list). This is a 2 week call ending
> Thursday, November 24th, 2016.
> Can the authors also reply to this mail indicating whether they know of
> any IPR related to this draft?
> Thanks,
> Chris.
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