[arin-ppml] ARIN Draft Policy 2011-5: Shared Transition Space

[William Herrin]

On Tue, Jul 5, 2011 at 5:30 PM, Owen DeLong <owen at delong.com> wrote:
> On Jul 5, 2011, at 2:24 PM, William Herrin wrote:
>> On Tue, Jul 5, 2011 at 5:13 PM, Owen DeLong <owen at delong.com> wrote:
>>> On Jul 5, 2011, at 2:01 PM, William Herrin wrote:
>>>> 2. Router interface numbering is a potential use case. Filtering of
>>>> RFC1918 is too widespread to overcome, so using it outside the NAT
>>>> breaks path MTU detection. That's not inherently true of this new
>>>> space and nonfiltering could be encouraged in a way that renders it
>>>> usable in a few years.
>>>
>>> Not really... How would you know which ISP to route the packet
>>> back to?
>>
>> You don't care. The packets you care about receiving from the router
>> are ICMP type 3 (destination unreachable) and ICMP type 11 (time
>> exceeded) . Those flow only one direction -- from the router back
>> towards you.
>
> If a packet is inbound towards me and needs fragmentation, for PMTU
> discovery, then, an ICMP type 3 would be sent back towards the
> originator of said packet.

Correct, but the originator doesn't care what address that packet
comes from and doesn't attempt to reply to it.

Regards,
Bill Herrin




-- 
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