Subject: Comments on IPv6 Prefix Subdelegation

From: Fred Baker <[email-masked]>
Date: Mon, 27 Jul 2009 14:09:20 +0200

Let me make an introductory comment on:
http://tools.ietf.org/html/draft-baker-ipv6-prefix-subdelegation
  "Prefix Sub-delegation in a SOHO/SMB Environment", Fred Baker, 27- 
Jul-09,
  <draft-baker-ipv6-prefix-subdelegation-00.txt>

In IPv6 Operations, we have two posted documents right now that  
comment on prefix subdelegation. These are:

http://tools.ietf.org/html/draft-donley-ipv6-cpe-rtr-use-cases-and-reqs
  "Use Cases and Requirements for an IPv6 CPE Router", Chris Donley,  
Deepak
  Kharbanda, John Jason Brzozowski, Yiu Lee, Jason Weil, Kirk  
Erichsen, Lee
  Howard, Jean-Francois Tremblay, 2-Jul-09,
  <draft-donley-ipv6-cpe-rtr-use-cases-and-reqs-00.txt>

http://tools.ietf.org/html/draft-ietf-v6ops-ipv6-cpe-router
  "IPv6 CPE Router Recommendations", Hemant Singh, Wes Beebee, 25- 
Mar-09,
  <draft-ietf-v6ops-ipv6-cpe-router-00.txt>

The premise is that an ISP might delegate a PA prefix to a SOHO/SMB  
network, perhaps using DHCP or etc. It would be nice if the prefix  
could be in turn sliced into /64 prefixes and sub-delegated to the  
various LANs in the subsidiary network.

draft-ietf-v6ops-ipv6-cpe-router is trying to recommend to vendors  
that they should build CPE routers in a certain way, and specifies in  
part how sub-delegation would work. In my opinion as WG chair, I would  
rather that it said "do RFC X" than "do the following algorithm", as  
one might want to change the algorithm and the proposed algorithm has  
not been proven operationally. In general, I would like 6man to take  
on the work of describing that algorithm.

I threw draft-baker-ipv6-prefix-subdelegation together very quickly  
for the purpose of saying "I would want you to reference something  
like <this>". That said, it is at least a first step, and may be the  
right answer for the moment. I would appreciate it if 6man could take  
a look at the discussion on sub-delegation in the two CPE drafts and  
at this draft, and decide first whether the draft is a reasonable  
first step toward solving the problem that the CPE drafts target, and  
then further decide whether and with what authors they would like to  
finish that discussion. I'm throwing no personal ego in here - if  
someone else would like to respond to the question, less work on my  
part sounds good to me.

Your opinions, please...

---

From: "Erichsen, Kirk" <[email-masked]>
Date: Mon, 27 Jul 2009 09:38:34 -0400

Fred,
 
Organizationally, I agree with your asersion that referencing another document to describe the sub-delegation behavior gives some wiggle room.
 
-KE

________________________________

From: Fred Baker [mailto:[email-masked]]
Sent: Mon 7/27/2009 6:09 AM
To: IETF IPv6 Mailing List
Cc: [email-masked]; [email-masked]
Subject: Comments on IPv6 Prefix Subdelegation

Your opinions, please...

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From: "Azinger, Marla" <[email-masked]>
Date: Tue, 28 Jul 2009 05:39:16 -0400

Hi Fred-

Here are my thoughts after the first read:

1.  Im really not sure an IETF document is really needed here.  What you wrote is an example of justification in a manner.  I agree some people probably need some papers to read that will get their minds thinking in an IPv6 sub delegation manner, but Im not sure if this should be an IETF doc or more just an informational paper sent to all the RIR's or posted on the NRO website.

2.  I have concern regarding the suggestions in section 2.3   Am I interpreting this correctly that you are suggesting upstreams do OSPF over VPN with residential customers?  That is something my network wont approve. I know there are some smaller networks that will do this, but I would suggest staying away from suggesting this as a good way of doing things.  Granted I know you didnt say this is a "good way" to do things, but it just makes me a little leary to even have it in the document.

Thats my 2 cents.  Thank you for working on this
Marla

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Fred Baker
Sent: Monday, July 27, 2009 5:09 AM
To: IETF IPv6 Mailing List
Cc: [email-masked]; [email-masked]
Subject: Comments on IPv6 Prefix Subdelegation

Let me make an introductory comment on:
http://tools.ietf.org/html/draft-baker-ipv6-prefix-subdelegation
  "Prefix Sub-delegation in a SOHO/SMB Environment", Fred Baker, 27- Jul-09,
  <draft-baker-ipv6-prefix-subdelegation-00.txt>

In IPv6 Operations, we have two posted documents right now that comment on prefix subdelegation. These are:

http://tools.ietf.org/html/draft-donley-ipv6-cpe-rtr-use-cases-and-reqs
  "Use Cases and Requirements for an IPv6 CPE Router", Chris Donley, Deepak
  Kharbanda, John Jason Brzozowski, Yiu Lee, Jason Weil, Kirk Erichsen, Lee
  Howard, Jean-Francois Tremblay, 2-Jul-09,
  <draft-donley-ipv6-cpe-rtr-use-cases-and-reqs-00.txt>

http://tools.ietf.org/html/draft-ietf-v6ops-ipv6-cpe-router
  "IPv6 CPE Router Recommendations", Hemant Singh, Wes Beebee, 25- Mar-09,
  <draft-ietf-v6ops-ipv6-cpe-router-00.txt>

The premise is that an ISP might delegate a PA prefix to a SOHO/SMB network, perhaps using DHCP or etc. It would be nice if the prefix could be in turn sliced into /64 prefixes and sub-delegated to the various LANs in the subsidiary network.

draft-ietf-v6ops-ipv6-cpe-router is trying to recommend to vendors that they should build CPE routers in a certain way, and specifies in part how sub-delegation would work. In my opinion as WG chair, I would rather that it said "do RFC X" than "do the following algorithm", as one might want to change the algorithm and the proposed algorithm has not been proven operationally. In general, I would like 6man to take on the work of describing that algorithm.

I threw draft-baker-ipv6-prefix-subdelegation together very quickly for the purpose of saying "I would want you to reference something like <this>". That said, it is at least a first step, and may be the right answer for the moment. I would appreciate it if 6man could take a look at the discussion on sub-delegation in the two CPE drafts and at this draft, and decide first whether the draft is a reasonable first step toward solving the problem that the CPE drafts target, and then further decide whether and with what authors they would like to finish that discussion. I'm throwing no personal ego in here - if someone else would like to respond to the question, less work on my part sounds good to me.

Your opinions, please...
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---

From: Fred Baker <[email-masked]>
Date: Tue, 28 Jul 2009 11:59:06 +0200

On Jul 28, 2009, at 11:39 AM, Azinger, Marla wrote:

> 2.  I have concern regarding the suggestions in section 2.3   Am I  
> interpreting this correctly that you are suggesting upstreams do  
> OSPF over VPN with residential customers?

within their homes?

No, I am suggesting that in a home that has more than one router, one  
might want an IGP, just like one does in other places.

---

From: "Azinger, Marla" <[email-masked]>
Date: Tue, 28 Jul 2009 07:24:46 -0400

Im thinking one step further than the double routers.  For example if these routers are not serviced by something at least the service type of a dedicated T1 to each router then they would be doing VPN.  So there are more requirements that need to be met here to make OSPF a realistic option.

Thank you
Marla

-----Original Message-----
From: Fred Baker [mailto:[email-masked]] 
Sent: Tuesday, July 28, 2009 2:59 AM
To: Azinger, Marla
Cc: IETF IPv6 Mailing List; [email-masked]; [email-masked]
Subject: Re: Comments on IPv6 Prefix Subdelegation

On Jul 28, 2009, at 11:39 AM, Azinger, Marla wrote:

> interpreting this correctly that you are suggesting upstreams do OSPF 
> over VPN with residential customers?

within their homes?

No, I am suggesting that in a home that has more than one router, one might want an IGP, just like one does in other places.

---

From: Fred Baker <[email-masked]>
Date: Wed, 29 Jul 2009 07:06:00 +0200

Maybe you can help me reword it. What I am getting at is this:

a) within the home, in the example in figure 3, I have four routers  
and nine IP subnets. For each router to know where in the home to send  
data, the usual thing is for the routers in the home to do is  
communicate with the others using a routing protocol.

b) there are two CPE routers, each of which has an upstream router in  
its ISP. Since they are not exchanging a routing protocol with their  
upstream, they will need a static route in their own tables and to  
advertise a default upstream route within the home.

c) RFC 3704 observes on the ingress filtering performed in the  
upstream routers, and suggests that the two CPE routers should have  
some way to ensure that they only send traffic that will pass the  
filter to their upstream. Hence, each CPE Router might have a filter  
installed that looks at the source address of a datagram and when  
necessary forwards it to the other CPE. Or if we had source/ 
destination routing, could advertise the relevant prefix with its  
default route, so that the three routers (not CPE routers, just plain  
old routers, but probably with a firewall filter configured due to the  
observation about corporate information security policies applying to  
telecommuting home offices) would be able to send traffic to the right  
CPE.

How would you suggest I word this? In my mind, taking what is written  
there and confusing it with the relationship with the upstream ISP  
requires a strange reading of the text, which is all about routing  
within the home.

On Jul 28, 2009, at 3:51 PM, Azinger, Marla wrote:

>
> Fred:  Here is the paragraph that is worded in a way that leads me  
> to thinking you are saying to do OSPF to the upstream.  I believe  
> something needs to be taken out or added to clarify it:
>
> Routing in such an environment calls for a routing protocol such as
>   RIPv6 [RFC2080], IS-IS [RFC5308], or OSPF [RFC5340].  In addition,
>   each CPE router will need to install a static default route upstream
>   and advertise a default route in the chosen routing protocol.  The
>   issues raised in [RFC3704] also apply, meaning that the two CPE
>   routers may each need to observe the source addresses in datagrams
>   they handle to divert them to the other CPE to handle upstream
>
> From: Azinger, Marla
> Sent: Tuesday, July 28, 2009 4:25 AM
> To: 'Fred Baker'
> Cc: IETF IPv6 Mailing List; [email-masked] 
> ; [email-masked]
> Subject: RE: Comments on IPv6 Prefix Subdelegation
>
> Im thinking one step further than the double routers.  For example  
> if these routers are not serviced by something at least the service  
> type of a dedicated T1 to each router then they would be doing VPN.   
> So there are more requirements that need to be met here to make OSPF  
> a realistic option.
>
> Thank you
> Marla
>
> Cc: IETF IPv6 Mailing List; [email-masked] 
> ; [email-masked]
> No, I am suggesting that in a home that has more than one router,  
> one might want an IGP, just like one does in other places.

---

From: "Azinger, Marla" <[email-masked]>
Date: Wed, 29 Jul 2009 04:35:03 -0400

I think having some wording on it pertaining to the homes internal upstream might work.  I massaged the paragraph a little and included that clarification.  So what do you think of this:

Routing in such an environment calls for a routing protocol. Each CPE must run either RIPv6 [RFC2080], IS-IS [RFC5308], or OSPF [RFC5340] on a default route and to the homes interal upstream a static default route. The issues raised in [RFC3704] also apply, meaning that the two CPE routers may each need to observe the source addresses in datagrams  they handle to divert them to the other CPE to handle upstream 

-----Original Message-----
From: Fred Baker [mailto:[email-masked]] 
Sent: Tuesday, July 28, 2009 10:06 PM
To: Azinger, Marla
Cc: IETF IPv6 Mailing List; [email-masked]; [email-masked]
Subject: Re: Comments on IPv6 Prefix Subdelegation

a) within the home, in the example in figure 3, I have four routers and nine IP subnets. For each router to know where in the home to send data, the usual thing is for the routers in the home to do is communicate with the others using a routing protocol.

b) there are two CPE routers, each of which has an upstream router in its ISP. Since they are not exchanging a routing protocol with their upstream, they will need a static route in their own tables and to advertise a default upstream route within the home.

c) RFC 3704 observes on the ingress filtering performed in the upstream routers, and suggests that the two CPE routers should have some way to ensure that they only send traffic that will pass the filter to their upstream. Hence, each CPE Router might have a filter installed that looks at the source address of a datagram and when necessary forwards it to the other CPE. Or if we had source/ destination routing, could advertise the relevant prefix with its default route, so that the three routers (not CPE routers, just plain old routers, but probably with a firewall filter configured due to the observation about corporate information security policies applying to telecommuting home offices) would be able to send traffic to the right CPE.

How would you suggest I word this? In my mind, taking what is written there and confusing it with the relationship with the upstream ISP requires a strange reading of the text, which is all about routing within the home.

On Jul 28, 2009, at 3:51 PM, Azinger, Marla wrote:

>
> Fred:  Here is the paragraph that is worded in a way that leads me to 
> thinking you are saying to do OSPF to the upstream.  I believe 
> Cc: IETF IPv6 Mailing List; 
> [email-masked]
> Im thinking one step further than the double routers.  For example if 
> these routers are not serviced by something at least the service
> So there are more requirements that need to be met here to make OSPF a 
> realistic option.
>
> Thank you
> Marla
>
> Cc: IETF IPv6 Mailing List; 
> [email-masked]

---

From: Fred Baker <[email-masked]>
Date: Wed, 29 Jul 2009 12:05:02 +0200

On Jul 29, 2009, at 10:35 AM, Azinger, Marla wrote:

> Routing in such an environment calls for a routing protocol. Each  
> CPE must run either RIPv6 [RFC2080], IS-IS [RFC5308], or OSPF  
> [RFC5340] on a default route and to the homes interal upstream a  
> static default route. The issues raised in [RFC3704] also apply,  
> meaning that the two CPE routers may each need to observe the source  
> addresses in datagrams  they handle to divert them to the other CPE  
> to handle upstream

I'll figure something out there. This makes it sound like only the CPE  
routers have to run a routing protocol; in fact, all of the routers in  
the home have to run a routing protocol. But yes, something like that.

---

From: "Azinger, Marla" <[email-masked]>
Date: Wed, 29 Jul 2009 07:32:26 -0400

Great.  Thank you Fred.

-----Original Message-----
From: Fred Baker [mailto:[email-masked]]
Sent: Wednesday, July 29, 2009 3:05 AM
To: Azinger, Marla
Cc: IETF IPv6 Mailing List; [email-masked]; [email-masked]
Subject: Re: Comments on IPv6 Prefix Subdelegation

On Jul 29, 2009, at 10:35 AM, Azinger, Marla wrote:

> Routing in such an environment calls for a routing protocol. Each CPE
> must run either RIPv6 [RFC2080], IS-IS [RFC5308], or OSPF [RFC5340] on
> a default route and to the homes interal upstream a static default
> route. The issues raised in [RFC3704] also apply, meaning that the two
> CPE routers may each need to observe the source addresses in datagrams

I'll figure something out there. This makes it sound like only the CPE routers have to run a routing protocol; in fact, all of the routers in the home have to run a routing protocol. But yes, something like that.

---

From: John Jason Brzozowski <[email-masked]>
Date: Wed, 29 Jul 2009 16:45:04 +0200

Only opinion I have is, it seems to makes sense to have the algorithm text
worked in 6man.

The network models standard delegation (non-hierarchical) versus advanced
delegation (hierarchical) would still reside in a CPE requirements draft
right in v6ops?

John
=========================================
John Jason Brzozowski
Comcast Corporation
e) mailto:[email-masked]
m) 609-377-6594
=========================================

> From: Fred Baker <[email-masked]>
> Date: Mon, 27 Jul 2009 08:09:20 -0400
> To: IETF IPv6 Mailing List <[email-masked]>
> Cc: <[email-masked]>,
> <[email-masked]>

---

From: John Jason Brzozowski <[email-masked]>
Date: Wed, 29 Jul 2009 17:33:06 +0200

Inline

> From: "Azinger, Marla" <[email-masked]>
> Date: Tue, 28 Jul 2009 05:39:16 -0400
> To: Fred Baker <[email-masked]>, IETF IPv6 Mailing List <[email-masked]>
> 1.  Im really not sure an IETF document is really needed here.  What you wrote
> is an example of justification in a manner.  I agree some people probably need
> some papers to read that will get their minds thinking in an IPv6 sub
> delegation manner, but Im not sure if this should be an IETF doc or more just
> an informational paper sent to all the RIR's or posted on the NRO website.
[jjmb] I think it is important to enumerate the deployment models which is a
v6ops topic.  The algorithm I think providing guidance related to the
algorithm for implementers would be useful.
> interpreting this correctly that you are suggesting upstreams do OSPF over VPN
> with residential customers?  That is something my network wont approve. I know
> there are some smaller networks that will do this, but I would suggest staying
> away from suggesting this as a good way of doing things.  Granted I know you
> didnt say this is a "good way" to do things, but it just makes me a little
> leary to even have it in the document.
[jjmb] Agree in principle with the OSPF comment above.

---

From: "Stark, Barbara" <[email-masked]>
Date: Wed, 29 Jul 2009 17:03:34 -0400

I'm sorry if the following questions show my ignorance, but, here
goes...

Why does it need to be a dynamic routing protocol? Why not a simple
configuration protocol, like with RFC 4191 or a DHCPv6 option as
suggested in
http://tools.ietf.org/html/draft-dec-dhcpv6-route-option-01? 

Why do the peered routers (such as CPE RTR 1 and 2, in Fig 3) need to
know which routes other routers claim to serve? There shouldn't be
misdirected traffic, if the  routes are known to downstream devices. Or
is it the home/office RTRs (Fig 3) who need to know which prefixes have
been assigned to each other, advertising on their WAN interfaces? It
seems like if the home/office RTRs don't know about each other, it
doesn't really hurt efficiency that much; it'll still work. They'll send
the messages up to the next hop (CPE RTR) serving that prefix, and then
it'll get routed down to the right home/office RTR.

If peered CPE RTRs do need to know each others' routes, why can't they
get it through an RFC 4191 or DHCPv6 method (this would be on the LAN
interface). I realize that there are those who say it's wrong for them
to solicit (RS or DHCPv6) on their LAN interfaces -- but why is it
wrong?

And don't these routes need to get propagated down to the hosts, because
hosts may individually have multiple interfaces (e.g., smartphone with
Wi-Fi and 3G)?
Barbara

> From: [email-masked] [mailto:[email-masked]] On Behalf
Of
> Fred Baker
> Sent: Wednesday, July 29, 2009 6:05 AM
> To: Azinger, Marla
> Cc: [email-masked];
draft-donley-ipv6-
> [email-masked]; IETF IPv6 Mailing List

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 07:53:30 +0200

> know which routes other routers claim to serve?

Um, what does a router do? Look at the example in the text and ask  
yourself if you want an average user (my canonical "average user"  
being my daughter, who wanted me to come to her house to install a  
camera on her computer so she could use it on Skype - "did you try  
plugging it in?") manually installing routes in each of the four  
routers when they could in fact learn them from each other directly?

> There shouldn't be misdirected traffic, if the routes are known to  
> downstream devices.

Not so. First, communications are not limited to accesses to systems  
outside the SOHO - music, for example, is often an access to a server  
in the home. Second, the fact that a datagram was delivered to a  
device in the home via one CPE is no guarantee that its response will  
use the same CPE.

> Or

... This comes back to my question about manual configuration. If I  
can make it work easily, what is the argument for not doing so?

> hosts may individually have multiple interfaces (e.g., smartphone with

That gets into a much larger discussion. Willing to go there, but  
that's beyond this draft.

---

From: Mikael Abrahamsson <[email-masked]>
Date: Thu, 30 Jul 2009 09:21:50 +0200 (CEST)

On Thu, 30 Jul 2009, Fred Baker wrote:

> yourself if you want an average user (my canonical "average user" being 
> my daughter, who wanted me to come to her house to install a camera on 
> her computer so she could use it on Skype - "did you try plugging it 
> in?") manually installing routes in each of the four routers when they 
> could in fact learn them from each other directly?

So, looking at this from another angle, namely deployment. I'm a router 
engineer, I support the use of routing protocols as much as the next 
router engineer, but I think a good question to ask is whether most home 
CPE vendors think RIP for IPv6 is hard to implement, or if this is 
something they consider easy?

If it's easy to implement RIP for IPv6 then I'm a proponent for that 
model.

Fred, (just checking) the model you're advocating then is that DHCPv6-PD 
from the main home CPE (with WAN connection) hands out subnets which are 
then announced to all home gateways via RIP(v6) ?

-- 
Mikael Abrahamsson    email: [email-masked]

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 09:38:28 +0200

> that's beyond this draft.

and by the way, propagating the routes to the hosts will not happen  
apart from a protocol that propagates routes, as in "a routing  
protocol".

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 10:04:23 +0200

On Jul 30, 2009, at 9:21 AM, Mikael Abrahamsson wrote:
> So, looking at this from another angle, namely deployment. I'm a  
> router engineer, I support the use of routing protocols as much as  
> the next router engineer, but I think a good question to ask is  
> whether most home CPE vendors think RIP for IPv6 is hard to  
> implement, or if this is something they consider easy?
>

Linksys and Cisco (which in this context represent completely separate  
product lines, one based on ODM sources and one based on IOS) both  
support RIP; the IOS products support all relevant IGPs.

> Fred, (just checking) the model you're advocating then is that  
> DHCPv6-PD from the main home CPE (with WAN connection) hands out  
> subnets which are then announced to all home gateways via RIP(v6) ?

What I am suggesting is that:

   a) DHCPv6-PD is very likely used by the ISP to delegate a prefix
      to the CPE (although I know of providers that would prefer to
      use an option on an RA to do this)
   b) the CPE router installs a default route to its upstream (duh)
   c) the CPE assigns some of the implied /64s to its interfaces as
      described in 2.1 and 2.2
   d.1) in a home with one router, that being the CPE, we're done

   d.2) <something> may, in cases like the 2.3 case, sub-delegate
        prefixes by some algorithm to other routers in the SOHO/SMB.
   e) in a SOHO/SMB with multiple CPEs or with internal routing,
      routers will need to communicate within the SOHO/SMB about
      routes. For that, I would suggest the use of an IGP routing
      protocol as opposed to manual static configuration.

As I observed Tuesday in v6ops, (d.2) is largely undefined; one could  
use DHCP-PD, but one could also imagine something akin to or using RFC  
2894, or other approaches. Section 2.3 clearly has the allocation  
process (which could be in the CPE Router and probably is, but doesn't  
have to be) have some notion of a map of the SOHO/SMB; 2.3 is tree  
structured and therefore pretty simple (the CPE allocates a /63 to  
each of three downstream routers), but a network with a cut-set of two  
(which I would hope any self-respecting SMB would deploy) would need  
something more comprehensive. For example, in

                    /-------+-/   /
                    prefix:2|     |
                        +---+--+  |
                        |Office|  |
                        |RTR 1 +--+                 --
                        +---+--+  |  +-------+     /
                    prefix:3|     |  |CPE RTR|    |
                    /-------+-/   +--+ISP 1  +------ ISP 1
                                  |  +-------+    |
                    /-------+-/   |p               \
                    prefix:4|     |r                --
                        +---+--+  |e
                        |Office|  |f
                        |RTR 2 +--+i
                        +---+--+  |x
                    prefix:5|     |:                --
                    /-------+-/   |0 +-------+     /
                                  |  |CPE RTR|    |
                    /-------+-/   +--+ISP 2  +------ ISP 2
                    prefix:6|     |  +-------+    |
                        +---+--+  |                \
                        |Home  |  |                 --
                        |RTR   +--+
                        +---+--+  |
                    prefix:7|     |
                    /-------+-/   /

                           Figure 3: Complex SOHO

if prefix:6 and prefix:0 are in fact the same wired network or 802.11  
SSID, we would want the "Home Router" to figure that out and use  
prefix:0 without trying to allocate ...:6 to it.

---

From: Ole Troan <[email-masked]>
Date: Thu, 30 Jul 2009 13:29:42 +0200

Mikael,

> If it's easy to implement RIP for IPv6 then I'm a proponent for that  

RIP is by far the easiest routing protocol to implement. and yes it is  
very easy.
as a side note if anyone remembers the "zerorouter?" BOF work going on  
a few years back one solution to solving subnet id election and  
arbitrary topology was to use new LSAs for OSPF.

in any case aren't there enough open source implementations around for  
any routing protocol? wouldn't think a CPE vendor would need to  
implement it themselves from scratch.

> subnets which are then announced to all home gateways via RIP(v6) ?

each requesting router i.e the router which has received the sub  
delegation will advertise that prefix.

cheers,
Ole

---

From: Ole Troan <[email-masked]>
Date: Thu, 30 Jul 2009 13:39:06 +0200

Barbara,

> to solicit (RS or DHCPv6) on their LAN interfaces -- but why is it

the problem with static routes as you suggest here is just that, that  
they are static. a dynamic routing protocol would handle convergence,  
loops. with RFC4191 or DHCPv6 static route option there is no way for  
the owner of that prefix to signal that the route is no longer  
available.

Markus and I have an expired draft going in more detail on DHCP PD  
route injection here:
http://tools.ietf.org/html/draft-stenberg-v6ops-pd-route-maintenance-00
even though it is mainly focused on PD across a administrative  
boundary. in the home network the security issue of having the  
requesting router advertise the route doesn't exist.

> hosts may individually have multiple interfaces (e.g., smartphone with

if a multi-homed host should participate in routing? possibly... but  
should we leave that for another day?

cheers,
Ole

---

From: Ole Troan <[email-masked]>
Date: Thu, 30 Jul 2009 13:55:43 +0200

Yiu,

> IMHO, it is high bar for the operators to support dynamic routing  
> protocol
> for residential customers. Today, each access router can easily  
> support
> thousands of customers. Imagine the access router needs to receive  
> thousands
> if not millions updates every few minutes, I am not sure the route  
> process
> is built to support this kind of load. Besides, if the CPE is  
> compromised
> and inject some routes didn't belong to it, it will create security  
> issue.

no, no... this is not the model I'm talking about. there will be no  
dynamic routing protocol in the access network.
this is purely in the home network, from the CPE and downstream.

cheers,
Ole

---

From: "Yiu L. Lee" <[email-masked]>
Date: Thu, 30 Jul 2009 07:52:36 -0400

Hi Ole,

IMHO, it is high bar for the operators to support dynamic routing protocol
for residential customers. Today, each access router can easily support
thousands of customers. Imagine the access router needs to receive thousands
if not millions updates every few minutes, I am not sure the route process
is built to support this kind of load. Besides, if the CPE is compromised
and inject some routes didn't belong to it, it will create security issue.

Regards,
Yiu

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 14:06:05 +0200

On Jul 30, 2009, at 1:52 PM, Yiu L. Lee wrote:

> for residential customers.

Several people have made that comment. In which draft is this proposed?

---

From: <[email-masked]>
Date: Thu, 30 Jul 2009 09:42:15 -0400

My comment to the advanced home network as described in the Small Multi-router network section is that it appears to go beyond the scope of a standard residential network. Sure there are those running multiple carrier-grade routers in their basement on the far end but these networks are not the typical home network. I do feel we need a specification for the delegation of PD into a routed network, but I would argue that the scope for prefix subdelgation in a multi-router network implementing dynamic routing protocols would go well beyond the bleeding edge residential user.

Also it may be helpful to expand the diagram to show at least one CPE router containing two upstreams to the same or different provider. 

Thanks,

Jason Weil
Network Architecture
Cox Communications
Phone: 404-269-6809

---

From: John Jason Brzozowski <[email-masked]>
Date: Thu, 30 Jul 2009 17:10:48 +0200

Barbara,

Consider the following as well to facilitate route injection:

http://tools.ietf.org/wg/dhc/draft-ietf-dhc-dhcpv6-agentopt-delegate

It enables route injection into a provider network absent the need for a
dynamic routing protocol.

Additionally, if the router at the edge of the home network is
sub-delegating it is conceivable (perhaps certain) that it is aware of the
routing topology in the home.  It should at least be aware of all the next
hops, right?  We also need to consider what, if any, inefficiencies this
introduces in the home network.  I think you mention this below, if one of
the sub-delegated routers need to forward packets within the home it will
use its default route, punt to its northbound router which in turn should
have all the necessary routing information.  Does this seem logical?

John

> From: "Stark, Barbara" <[email-masked]>
> Date: Wed, 29 Jul 2009 17:03:34 -0400
> To: Fred Baker <[email-masked]>, "Azinger, Marla"
> <[email-masked]>
> <[email-masked]>, IETF IPv6
> Mailing List <[email-masked]>

---

From: "Yiu L. Lee" <[email-masked]>
Date: Thu, 30 Jul 2009 07:57:07 -0400

Aaah, ok. So we are on the same page ;-)

---

From: John Jason Brzozowski <[email-masked]>
Date: Thu, 30 Jul 2009 17:15:17 +0200

> Date: Thu, 30 Jul 2009 01:53:30 -0400
> To: "Stark, Barbara" <[email-masked]>
[jjmb] Agree here the notion of the user having to configure the network
manually is not going to fly.
> can make it work easily, what is the argument for not doing so?
[jjmb] there should not be an argument, alleviating manual configuration
where possible is the right thing.  This would not preclude more advanced
users from manually configuring whatever they like.

---

From: John Jason Brzozowski <[email-masked]>
Date: Thu, 30 Jul 2009 17:20:15 +0200

> From: Mikael Abrahamsson <[email-masked]>
> Organization: People's Front Against WWW
> Date: Thu, 30 Jul 2009 03:21:50 -0400
[jjmb] implementation difficulty is important as is making sure the
underlying hardware can support it.  Also we may be ok with a routing
protocol but what about someone who is not a router engineer?  Will it be
straightforward enough for everyone else to setup?

---

From: "Erichsen, Kirk" <[email-masked]>
Date: Thu, 30 Jul 2009 11:21:41 -0400

JJB, I'm reading that draft link you just sent out in response to IGP avoidance in multi-router HNs. I for one would like to avoid icky/sticky RIP'y or a heavier IGP if we can at all avoid it.
 
-KE 

From: John Jason Brzozowski [mailto:[email-masked]]
Sent: Thu 7/30/2009 9:20 AM
To: Mikael Abrahamsson; IETF IPv6 Mailing List
Cc: [email-masked]; [email-masked]
Subject: Re: Comments on IPv6 Prefix Subdelegation

---

From: John Jason Brzozowski <[email-masked]>
Date: Thu, 30 Jul 2009 17:39:38 +0200

> Date: Thu, 30 Jul 2009 04:04:23 -0400
> To: Mikael Abrahamsson <[email-masked]>
[jjmb] the above is the most likely the near term typical use case.

[jjmb] the items below are more advanced.  How far do we need to go with the
below?  Seems to me that we should enumerate some fundamental mechanisms
that can be used for sub-delegation.  We probably need to make sure we cover
how routes are distributed within the home.

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 18:12:55 +0200

> dynamic routing protocol.

and what in this discussion is relevant to the provider network?

Everything I am talking about is inside the user's home.

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 18:16:55 +0200

On Jul 30, 2009, at 5:20 PM, John Jason Brzozowski wrote:

> Will it be

For a person that has the problem described in 2.3, it's one click on  
a Linksys router. I would imagine it is not so very different for  
other companies.

---

From: Fred Baker <[email-masked]>
Date: Thu, 30 Jul 2009 18:18:00 +0200

> how routes are distributed within the home.

If you have read the draft, it says that, in so many words.

---

From: John Jason Brzozowski <[email-masked]>
Date: Thu, 30 Jul 2009 18:28:56 +0200

It was in reply to an earlier comment.  This is the extent of its relevance.

> Date: Thu, 30 Jul 2009 12:12:55 -0400
> To: John Jason Brzozowski <[email-masked]>
> Cc: "Stark, Barbara" <[email-masked]>, "Azinger, Marla"
> <[email-masked]>,
> <[email-masked]>,