IPv6 /64 links (was Re: ipv6 book recommendations?)

Masataka Ohta mohta at necom830.hpcl.titech.ac.jp
Wed Jun 13 04:23:35 UTC 2012


Owen DeLong wrote:

>> Any multicast capable link is broadcast capable.
> 
> BZZT! but thank you for playing.
> 
> Many NBMA topologies support multicast.

When you specify a "link" as a small subset of NBMA, it is
broadcast capable, as was demonstrated by history of CLIP.

If you want to have a large (as large as broadcast is not
practical) "link" in NBMA, multicast control messages
badly implode.

>>> So leveraging broadcast is why just about every implementation does a
>>> gratuitous ARP-and-wait multiple times,

>> Not at all. IPv4 over something does not have to be ARP.

> IPv4 over anything requires some form of L2 address resolution in any case
> where L2 addresses must be discovered.

For a mobile link around a base station, during link set up,
the base station and mobile hosts know MAC addresses of each
other. The base station can (or, must, in case of hidden
terminals) relay packets between mobile hosts attacked to it.

There is no ARP nor ARP-and-wait necessary.

>> IPv6 is broken eventually requiring all link use ND, even
>> though ND was designed for stational hosts with only Ethernet,
>> PPP and ATM (with a lot of misunderstanding) in mind.

> Not really.

I know it happening within WG discussions.

> End-to-end is significantly more broken in IPv4 because of
> the need for NAT than it is in IPv6.

More? So, even you think IPv6 is more or less broken.

> IIRC, you were the one promoting even more borked forms
> of NAT to try and compensate for this.

I just need a UPnP capable NAT to restore the end to end
transparency.

> IPv6 is quite a bit better than IPv4 in many ways. It could be better still, but, it is definitely superior
> to current IPv4 implementations and vastly superior to the IPv4 implementations that existed when
> IPv6 was designed.

That is a commonly heard propaganda. However, these days,
few believe it.

Actually in this thread, your statement is proven to be
untrue w.r.t. amount of noises on link bandwidth in large
links.

						Masataka Ohta




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