Link local for P-t-P links? (Was: IPv6 prefixes longer then /64: are they possible in DOCSIS networks?)

Jimmy Hess mysidia at
Thu Dec 1 05:32:37 UTC 2011

On Wed, Nov 30, 2011 at 10:33 PM, McCall, Gabriel
<Gabriel.McCall at> wrote:
> Well, traceroutes and other ICMP functions would break. It is occasionally useful to be able to address a specific router interface from someplace other than its connected peer.

Unless your router always sources TTL exceeded from a loopback interface,
breaking traceroute is a problem...  breaking ICMP probing is even worse.

I realize IPv6 is the utopian protocol we've all been waiting for,
where routers failing,
latency, packet loss, and hardware glitches are all going to be very
distant memories,
so the familiar troubleshooting tools can all go away  and the minor
status questions can be diagnosed using a SNMP status check,

But in the unlikely event something did ever go slightly wrong,
having link locals on routers would
be a killer for the user.

This definitely isn't better than using long prefixes on the P-t-P links.



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