It's Ars Tech's turn to bang the IPv4 exhaustion drum
nanog at ian.co.uk
Sat Aug 23 20:41:16 CDT 2008
On 21 Aug 2008, at 09:09, Iljitsch van Beijnum wrote:
> On 20 aug 2008, at 21:33, Crist Clark wrote:
>> No, that's my point. On a true point-to-point link, there is
>> only one other address on the link. That's what point-to-point
>> For example, on the IPv4 ends gif(4) tunnel in my previous message,
>> gif0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1280
>> tunnel inet 18.104.22.168 --> 22.214.171.124
>> inet6 fe80::200:24ff:feca:91b4%gif0 prefixlen 64 scopeid 0x7
>> inet6 2001:470:1f04:2fc::2 --> 2001:470:1f04:2fc::1
>> prefixlen 128
> Note that this interface doesn't _have_ any IPv4 addresses: the
> IPv4 addresses that you see are the tunnel endpoints.
> However, the IPv6 addresses do what you say: there is a local one
> and a remote one and they don't share a subnet. Obviously it's
> possible to do this, but in my opinion, this is just an
> implementation variation, not the natural state of point-to-point
> links. It makes much more sense to have one set of behaviors that
> applies to all interfaces.
> And what is a point-to-point link, anyway? In theory gigabit
> ethernet is CSMA/CD, but I don't think anyone ever bothered to
> implement that, in practice it's point-to-point on layer 1, but
> layer 2 is point-to-multipoint...
1000BASE-PX10 and 1000BASE-PX20 are both point to multipoint at layer 1.
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