Re: WPD-6, WAA-8, and WAA-9 of draft-ietf-v6ops-ipv6-cpe-router-04

[Ole Troan <ot@cisco.com>]

Philip,

>>> I prefer to avoid unnumbered links. I think it is much less confusing =
>> if=20
>>> source addresses of error ICMPs are always addresses from the =
>> interface that
>>> generated the error.
>> 
>> these two paragraphs are mutually exclusive. you cannot require that an 
>> ICMP error is sourced from the interface that generated the error and at 
>> the same time require that a router use the strong host model.
> 
> Why? 

isn't that obvious?
if you generate an ICMP message from e.g Ethernet0 destined to a destination on Serial0?
since the error happened on Ethernet0, that's the address you want to use as a source for the ICMP. you cannot do this with the strong host model.

/ot


> 
> In the strong host model, every interface has a global address and some way 
> of forwarding packets to a default router. 
> 
> So the interface that generates the ICMP uses it's own address as the source
> of the ICMP and forwards it to a default router, which is typically the system
> itself because we are talking about a router, but it could be an default
> router.
> 
>