Big Temporary Networks

Masataka Ohta mohta at necom830.hpcl.titech.ac.jp
Fri Sep 21 03:54:49 UTC 2012


Tony Hain wrote:

>>> So, a single example of IPv4 behaving in a suboptimal manner would be
>>> enough to declare IPv4 not operational?
>>
>> For example?
> 
> Your own example ---

>> ...  that a very crowded train arrives at a station and all the smart
> phones of passengers try to connect to APs ...
> 
> IPv4 has a train load of devices unicasting and retransmitting all the
> dropped packets,

IPv4 merely need a broadcast ARP request and broadcast DHCP discover
to be piggy backed in a single IEEE802.11ai frame reliably unicast
to an AP.

> where an IPv6 multicast RA allows all the devices to
> configure based on reception of a single packet.

You miss multicast storm caused by DAD.

> Just because you personally want IPv6 to be nothing more than IPv4
> in every aspect is no reason to troll the nanog list and create
> confusion that causes others to delay their IPv6 deployment.

Just because IPv6 is working without much problem somehow somewhere
is not a valid reason to say others should use IPv6.

As IP is so essential to the Internet, IP protocol must be
perfect w.r.t. the scale and diversity of the Internet.

IPv4 has evolved so, as the Internet evolve.

IPv6 could have been so, if it were a exact copy of IPv4 save
address length.

But, it is not, which is why IPv6 failed on various points
which are different from IPv4.

> Your complaints about IPv6 behavior
> on wifi ignore the point that IPv6 ND behavior was defined before or in
> parallel as wifi was defined by a different committee.

The problem is "ND uber Alles" approach, which makes it impossible
to make "IP uber Alles".

> There will always be
> newer L2 technologies that arrive after an L3 protocol is defined, and the
> behavior of the L3 will be 'suboptimal' for the new L2. When the issue is
> serious enough to warrant documentation, addendum documents are issued.

Because of "ND uber Alles" approach, the document just says "IPv6
works suboptimal" without solving the issue.

OTOH with IPv4, the document can solve the problem by having
a new adaptation mechanism much different from ARP or PPP.

							Masataka Ohta




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