Re: Proposed change to draft-ietf-6man-multi-homed-host after IESG review

On 16 September 2016 at 09:10, Bob Hinden <bob.hinden@gmail.com> wrote:
> Brian,
>
> While I don’t have a strong objection to the proposed change, I am uncomfortable with what I read is a request to not even mention source-destation routing.

+1

Static policy based routing (given different names by different
vendors, e.g., Cisco call it Policy Based Routing, Juniper call it
Filter-Based Forwarding), which can include a policy based on source
address, has been around in implementations for at least 15 years. I
think the only thing new in this space is dynamic distribution of a
source address based forwarding "policy" via a routing protocol.

  I agree it should not be a requirement in this document, but I don’t
see anything wrong with a forward looking pointer.  Perhaps something
like this (based on the NEW text):
>
>   Network designs exist that can usefully limit themselves to static
>   routing (such as a simple tree network) or may internally use no
>   routers at all, such as a single LAN with two CE routers, each of
>   which leads to a different upstream network.  However, the
>   mechanism specified in this document may require some form of
>   support from the routing protocols used in some multihomed networks.
>   The details of such support are out of scope for this document.
>   One approach that is being investigated to provide the requisite support
>   in routing protocols is described in [I-D.ietf-rtgwg-dst-src-routing].
>
> Or similar.
>
> Bob
>

Regards,
Mark.

>
>> On Sep 15, 2016, at 1:53 PM, Brian E Carpenter <brian.e.carpenter@gmail.com> wrote:
>>
>> Hi,
>>
>> This message concerns
>> https://tools.ietf.org/html/draft-ietf-6man-multi-homed-host-09 .
>>
>> There is one remaining issue in the draft before it can get IESG approval.
>> One of the routing ADs proposes the following change. It does not affect
>> the normative content of the draft, but it is a technical change (deletion)
>> so we'd like to hear if there are any objections from the WG. Please comment
>> within a week (silence means no objection to this change). Some more
>> background is below the proposed change.
>>
>> OLD:
>>
>> 2.2.  Expectations of multihomed networks
>>
>>   The mechanism specified in this document requires some form of
>>   support from the routing protocols used in multihomed networks.  One
>>   such way of providing the requisite support in routing protocols is
>>   described in a routing protocol independent fashion
>>   [I-D.ietf-rtgwg-dst-src-routing].  Network designs exist that can
>>   usefully limit themselves to static routing (such as a simple tree
>>   network), or may internally use no routers at all, such as a single
>>   LAN with two CE routers, each of which leads to a different upstream
>>   network.
>>
>> NEW:
>>
>> 2.2.  Expectations of multihomed networks
>>
>>   Network designs exist that can usefully limit themselves to static
>>   routing (such as a simple tree network) or may internally use no
>>   routers at all, such as a single LAN with two CE routers, each of
>>   which leads to a different upstream network.  However, the
>>   mechanism specified in this document may require some form of
>>   support from the routing protocols used in some multihomed networks.
>>   The details of such support are out of scope for this document.
>>
>> You can see Alia's original DISCUSS comment dated 2016-08-02 at
>> https://datatracker.ietf.org/doc/draft-ietf-6man-multi-homed-host/history/ .
>> The "SHOULD" mentioned there has already been removed, but her considered
>> opinion is that the routing solution is simply out of scope for this draft.
>>
>> Regards
>>   Brian Carpenter
>>
>>
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