Subject: [mif] #5: only one default route? (there should be multiple, as for MIF WG)

From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:00:10 -0000

#5: only one default route?  (there should be multiple, as for MIF WG)

 Dear participants in MIF WG,

 Currently draft-ietf-mif-dhcpv6-route-option-04 specifies that only one
 default route to be configured by the DHCPv6 Server for a particular
 client.

 draft-ietf-mif-dhcpv6-route-option-04 says:
 "    Server MUST NOT define more than one default route."

 I do not know why this is so?

 In our implementation the DHCP Server delivers a list of default routes
 to the Client (draft-mouton...)  Also, ND configures a list of default
 routes on the same link.

 I find it a bit bizarre that in this group's context the Server is
 required so strongly to configure a single default route no more.

 I wanted to ask the oppinion of the group about this.

-- 
----------------------------------+-------------------------------------
 Reporter:  alexandru.petrescu@…  |      Owner:  Alexandru Petrescu
     Type:  enhancement           |     Status:  new
 Priority:  minor                 |  Milestone:  milestone1
Component:  dhcpv6-route-option   |    Version:
 Severity:  In WG Last Call       |   Keywords:  multiple default routes
----------------------------------+-------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5>
mif <http://tools.ietf.org/mif/>

---

From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:07:20 -0000

Changes (by alexandru.petrescu@…):

 * cc: alexandru.petrescu@… (added)

-- 
-------------------------------------+---------------------------------
 Reporter:  alexandru.petrescu@…     |       Owner:  Alexandru Petrescu
     Type:  enhancement              |      Status:  new
 Priority:  minor                    |   Milestone:  milestone1
Component:  dhcpv6-route-option      |     Version:
 Severity:  In WG Last Call          |  Resolution:
 Keywords:  multiple default routes  |
-------------------------------------+---------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:1>
mif <http://tools.ietf.org/mif/>

---

From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:19:00 -0000

Comment (by alexandru.petrescu@…):

 > to the Client (draft-mouton...) Also, ND configures a list of default

 Is also the following configuration out of scope for this group?

 - a home network with TWO ISP's providing connection
 - both without knowledge of each other
 - both send default and specific route(s) (RA or DHCP)

 IMHO, my home desktop should really be able to handle
 this too (router selection needs to consider which source
 address was picked from which router).

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Ticket URL: <https://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:2>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:19:18 -0000

> address was picked from which router).

 I think this is some of the stuff that 6man has been discussing.
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Ticket URL: <https://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:3>
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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:19:32 -0000

On 27 March 2012 13:50, Alexandru Petrescu <[email-masked]>
 wrote:
 > Le 27/03/2012 15:45, Erik Kline a écrit :
 >
 > Do you think that discussion may have concluded that it's not good to
 have
 > several default routes on the Client?

 The discussion I'm referring to is about updating the source address
 selection depending on the next hop.  This is obviously a more
 complicated issue overall, of course.  Unless you get it right, you're
 likely to run afoul of BCP38.

Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:4>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:19:54 -0000

> address was picked from which router).

 Yes, this seems to be in scope to me.   I think you should submit a draft,
 since you've described both the problem and the solution quite well.   You
 are describing the "two provisioning domains" scenario, FWIW.
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Ticket URL: <https://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:5>
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---

From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:20:28 -0000

On 27 March 2012 15:33, Ted Lemon <[email-masked]> wrote:
 >> Submit to 6man, I think.
 >
 > Thanks for telling us your opinion, Erik.   Is there a reason behind the
 opinion, or did it just spring into your mind like a tiny, perfect flower?

 I was thinking of the RFC3484bis work going on right now.  If there
 are changes that are needed there, it should get reviewed by the same
 group reviewing those other changes right now, yes?  It would be a
 shame if the two I-Ds crossed in flight, but obviously not the end of
 the world.
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Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:6>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:20:41 -0000

On 2012-03-28 04:30, Erik Kline wrote:
 > On 27 March 2012 15:26, Ted Lemon <[email-masked]> wrote:
 >> Yes, this seems to be in scope to me.   I think you should submit a
 draft, since you've described both the problem and the solution quite
 well.   You are describing the "two provisioning domains" scenario, FWIW.

 The phrase "more than one default route" on its own makes my head hurt,
 given the normal meaning in computer science of the word "default".

 One default route per source prefix in use makes perfect sense, in view
 of the need for address pair selection and ingress-filtering avoidance.
 (When I think about it, a default route even makes sense for a ULA
 prefix.)

 > Submit to 6man, I think.

 Clearly - the customers for this include MIF, homenet and shim6 to name
 only three.

     Brian

     Brian

Ticket URL: <https://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:7>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:20:59 -0000

On Wed, Mar 28, 2012 at 00:16, Brian E Carpenter
 <[email-masked]> wrote:

     The phrase "more than one default route" on its own makes my head
 hurt,
     given the normal meaning in computer science of the word "default".

     One default route per source prefix in use makes perfect sense, in
 view
     of the need for address pair selection and ingress-filtering
 avoidance.
     (When I think about it, a default route even makes sense for a ULA
 prefix.)

 No, multiple default routes make sense even when they're not source-
 specific. For example, they make sense when you have two routers and one
 of them can go down. Remember that a route includes a next-hop, and that
 RFC 4861 defines a default router list (which is a list of possible next-
 hops for the default route).

Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:8>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Wed, 01 Aug 2012 21:21:18 -0000

On 2012-03-28 21:33, Lorenzo Colitti wrote:
 > On Wed, Mar 28, 2012 at 00:16, Brian E Carpenter <
 > [email-masked]> wrote:
 >
 prefix.)
 >
 >
 > No, multiple default routes make sense even when they're not
 > source-specific. For example, they make sense when you have two routers
 and
 > one of them can go down. Remember that a route includes a next-hop, and
 > that RFC 4861 defines a default router list (which is a list of possible
 > next-hops for the default route).

 Fair enough, although if we were starting again there might be a better
 way
 of doing it.

       Brian

Ticket URL: <http://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:9>
mif <http://tools.ietf.org/mif/>

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From: "mif issue tracker" <[email-masked]>
Date: Thu, 02 Aug 2012 00:12:15 -0000

I will write this down here so I have a trace.

 I discussed 1aug2012 with a co-author and there seems to be strong
 opposition to multiple default routes for the following reasons.

 If a Host has several interfaces, then on each of these interfaces there
 would be different responding DHCP Server that would allocate data
 specific to that interface in particular.  It would be not reasonable for
 a DHCP Server answering to one interface of a Host to offer it
 configuration information for the other interface.

 An operator of both WiFi and 3G would deploy a different DHCP Server on
 each of the access routers of 3G and of WiFi (and would not use same DHCP
 Server to configure the cellular interface and the WiFi interface of the
 same Host).

 If you have two default routes in the same host then how to decide which
 is _the_ default route?  This is bad because it is difficult to decide so.
 Source-based routing is not good (I forgot why).

 Alex

Ticket URL: <https://trac.tools.ietf.org/wg/mif/trac/ticket/5#comment:10>
mif <http://tools.ietf.org/mif/>