Re: [Autoconf] what's a router (was: WC consensus call for RFC5889 modifications )

Alexandru Petrescu <> Thu, 05 August 2010 09:21 UTC

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Date: Thu, 05 Aug 2010 11:21:37 +0200
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Subject: Re: [Autoconf] what's a router (was: WC consensus call for RFC5889 modifications )
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Le 05/08/2010 10:38, Henning Rogge a écrit :
> On Wed August 4 2010 15:07:14 Charles E. Perkins wrote:
>> Hello Henning,
>> On 8/3/2010 10:55 PM, Henning Rogge wrote:
>>> If you run a part of the routing protocol to connect the "host" to the
>>> MANET, it's a router in my oppinion (Ripple would call it a leaf node
>>> for example).
>> What if your host gets an address by running
>> "autoconf.exe", which is not a routing program?
> Does your host set up a route towards the next router and maintains it if the
> topology data from the router changes ? If yes I would say it's a primitive
> router too. If no, it's not.

To me a router is a device and its software doing this:
- has a routing table called such.
- does longest-prefix match algorithm to search in it.  This operation
   is not specified (no RFC) but it is there everywhere in every router,
   thanks BSD.
- includes that route.h I believe as CP said.
- has multiple interfaces.

In a sense every other host (my Windows PC) is a router because it does 
all these things.  My PDA, my cell phone, are all routers.

 From this perspective, it is difficult to define what a Host is because 
everything seems to be a router to me - once it's connected to the 
Internet it is a router.  A supercomputer is a router too, though it 
won't route as a DFZ 192-processor router would route.


>>> If the node just use DHCP or similar protocols to get it's address
>>> without being modified to work with the MANET, it's no router (and don't
>>> need the autoconf address model).
>> What if the host does not?  Or, do you mean to say
>> that this discussion is a way to legislate that all
>> hosts must use DHCP?
> I don't think I ever said this. I just presented an example that the address
> model is not necessary for running a node in a MANET that use the autoconf
> address model.
> Yes, you CAN use it... but you don't need to.
>>> The autoconf model is NOT the only way for a host to get an address for
>>> connection to a MANET.
>> The autoconf model for getting addresses doesn't exist.
>> I sure hope it isn't the only way to get an address.
>> But suppose at some point there is an autoconf.exe.
>> It should be a way for a host to get an address.
>> Its connection to the MANET would, presumably allow
>> it to use this address.  Or, do you mean to say that
>> "address allocation" == "connection"?
> I don't see any reason why an autoconfiguration protocol developed by this
> group would only run on interfaces of routers.
>>> If you have a router with a policy that limits the routers functionality
>>> (in terms of the routing protocol), you could just write a
>>> compact/optimized version of the needed software part for it.
>> main()
>> {
>> 	system ("get_address");
>> 	if (routing) fail();   /* My compact routing code */
>> }
>> Am I a router?
> I don't see any routing code of a routing protocol. But I don't see your
> problem too.
>>>>> It should be done on the routers (but MANETs can and have been run
>>>>> with different address models), and it could be used for hosts closely
>>>>> attached to a MANET, but it's not necessary to do so.
>>>> What is "it"?
>>> The autoconf address model should be used on routers (but you could use a
>>> different one) and it (the address model) could be used on hosts attached
>>> to a MANET, but it's not necessary to use the autoconf address model on
>>> hosts.
>> It's necessary for hosts to adhere to the
>> considerations detailed in the address model
>> document.  I'm not sure if this is the same
>> as "using" it.
> It might be necessary, depending on what software the host is running.
>>>>> But in my opinion it is still better it's still better to restrict the
>>>>> title as suggested in the WG meeting consensus that to make it too
>>>>> generic.
>>>> I can't imagine any non-political reason whatsoever for this.
>>> If we do otherwise we could have the same problems. People would say "you
>>> demand that any computer attached to your MANET use the autoconf address
>>> model. But we have to use DHCP, so your address model is wrong."
>> This is a political argument not based on the needs
>> of the addressability, connectivity, or goals of
>> making an ad hoc network.  Insofar as you may be
>> nonetheless correct, I begin to believe that I have
>> zero insight into the technical goals of the discussion.
>>> (I don't say they are right, but we will get people with strange comments
>>> on the address model with both titles)
>> Please tell me if my comments are "strange".
> I think the problem you stated is that people can say "the title says it's
> only for routers, so it is not enough for my usecase and I need something
> different".
> If we not change the title we might get "the title says it's for all nodes,
> but I cannot force my users to install a special interface configuration on
> their smartphones, so I need something different."
> There are nodes in MANET that are a grey area between host and router. Because
> of this we cannot make a clear statement on what nodes the autoconf address
> model should be used.
> Most of the WG seems to think it's better to restrict the scope a little bit
> more and let people use it for other things than the defined scope if they
> think it's right (at least that's how I understand the consensus of the
> group).
> Henning Rogge
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