Re: [v6ops] Routers are hosts too! (Re: I-D Action: draft-ietf-v6ops-host-addr-availability-04.txt)

[joel jaeggli <[e-mail]>]

On 1/7/16 10:20 AM, Joe Touch wrote:
> 
> 
> On 1/7/2016 4:39 AM, Alexandre Petrescu wrote:
>>
>>
>> Le 06/01/2016 22:46, Joe Touch a écrit :
>>> +1 (and then some)
>>>
>>> AFAICT:
>>>
>>>     - a host is an Internet device that sources or sinks packets
>>>
>>>     - a router is an Internet device that *also* relays packets
>>>
>>> It may be possible to implement a router that never acts as a host, but
>>> that requires it never participate actively in routing protocols, IP
>>> signalling, etc.
>>
>> Yes.  And:
>>
>>         - a router doesn't use the information received in an RA, a
>>           host does.
> 
> A router might have an interface by which it is accessible as a host but
> for which it does not forward; that interface could use an RA for
> autoconfiguration.
> 
>>         - a router doesn't join the all-hosts multicast address.
> 
> There's an "all nodes", which it clearly should join (see RFC4921, Sec.
> 2.8).

the platonic conception of a router as a device that simply forwards
packets maybe not, the router's control plane on the other hand is a
host on every subnet where it's addressed and is therefore a node.

> There is no "all-hosts" listed here (except for ST, which is obsoleted): 
> http://www.iana.org/assignments/ipv6-multicast-addresses/ipv6-multicast-addresses.xhtml
> 
>>         - a router doesn't use SLAAC to configure an address for self,
>>           a Host does.
> 
> It could where appropriate (e.g., see first item above).
> 
>>         - a router does implement longest-matching algorithms, a Host
>>           doesn't.
> 
> This is needed for source address selection if the host has more than
> one address.
> 
>> Implementations are obviously less clear cut.  But we can talk theory.
>>
>> Alex
>>
>>>
>>> Joe
>>>
>>> On 1/6/2016 1:24 PM, Mark Smith wrote:
>>>> Routers are universally hosts too. The distinction between a router and
>>>> a host is that a router will also accept packets not sent to addresses
>>>> assigned to the devices interfaces. It will then see what to do with
>>>> them according to the route table, sending the packet where ever the
>>>> route table says or dropping them. That is all that makes it a router.
>>>
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>>
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