Re: Mirja Kühlewind's Discuss on draft-ietf-rtgwg-enterprise-pa-multihoming-08: (with DISCUSS and COMMENT)

Jen Linkova <> Mon, 01 July 2019 14:37 UTC

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From: Jen Linkova <>
Date: Tue, 2 Jul 2019 00:37:30 +1000
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Subject: =?UTF-8?Q?Re=3A_Mirja_K=C3=BChlewind=27s_Discuss_on_draft=2Dietf=2Drtgwg=2De?= =?UTF-8?Q?nterprise=2Dpa=2Dmultihoming=2D08=3A_=28with_DISCUSS_and_COMMENT=29?=
To: =?UTF-8?Q?Mirja_K=C3=BChlewind?= <>
Cc: The IESG <>, Ronald Bonica <>, rtgwg-chairs <>,, Routing WG <>
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Hi Mirja,

On Thu, Jun 27, 2019 at 1:12 AM Mirja Kühlewind via Datatracker
<>; wrote:
> I have a question basically on section 5.3, however, maybe I'm misunderstanding
> something or there is an open aspect here: If I have selected one IP address
> and then open a TCP connection and during using this TCP connection the
> connection to the selected ISP fails, my expected behaviour from a multi-homed
> network would have been that my traffic is simply rerouted to the other ISP.

Well, it would be the case if the enterprise network has its own
address space or using PI. Such networks are outside of the scope of
the document - the problem
does not exist for them. What the draft is talking about is the
scenario when a network (big or small) has to use address space
provided by an ISP.
In that case rerouting does not happen.

> However, all solutions discussed in sec 5.3. assume that the endpoint will
> switch its IP address. In case of TCP, which is not migration-capable, as
> indicated by the TSV-ART reviewer (Thanks Michael!), this would mean that I
> have to open a new TCP connection and start over again. That doesn't see
> optimal. Should this be considered?

I've added a section to discuss the solution limitations:

Please let me know if more clarification is required.

> I was also wondering about the question Alvaro raised in point B. I mean even
> if unscoped forwarding is used for internal traffic, this would probably still
> prevent spoofing, however, it doesn't seem correctly that unscoped forwarding
> table are not needed anymore.

Yes, good catch, it was an artifact, removed.

> Nit:
> Sec 6 s/This document defines a way for network/This document defines a way for
> networks/ or
>           s/This document defines a way for network/This document defines a way
>           for the network/

Fixed, thanks!

SY, Jen Linkova aka Furry