Internet Edge Router replacement - IPv6 route tablesizeconsiderations

James Stahr stahr at
Fri Mar 11 12:55:33 CST 2011

At 01:33 AM 3/11/2011, Owen DeLong wrote:

>On Mar 10, 2011, at 11:22 PM, Dobbins, Roland wrote:
> >
> > On Mar 11, 2011, at 2:02 PM, Owen DeLong wrote:
> >
> >> Frankly, unless you have parallel links, there isn't a definite 
> need to even number PtoP links for IPv6.
> >> Every thing you need to do with an interface specific address on 
> a PtoP link can be done with link local.
> >
> > Which is why IP unnumbered caught on so well in IPv4-land, heh?
> >
>There's a HUGE difference between IP unnumbered and link-local.
>Frankly, absent parallel links, there was a lot to be said for IP unnumbered
>and I think that if people had better understood the implications of where and
>when it was a good vs. bad idea and tied it properly to loopbacks instead
>of $RANDOM_INTERFACE, it might have caught on better.

Is anyone else considering only using link local for their PtoP 
links?  I realized while deploying our IPv6 infrastructure that 
OSPFv3 uses the link-local address in the routing table and than the 
global address, so if I want to have a routing table which makes 
sense, I need to statically assign a global address AND the 
link-local address.  Then I realized, why even assign a global in the 
first place?  Traceroutes replies end up using the loopback. BGP will 
use loopbacks.  So is there any obvious harm in this approach that I'm missing?


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