Re: Use of extended prefix lengths

[Mohacsi Janos <mohacsi@niif.hu>]

On Thu, 5 Jun 2008, Chuck Anderson wrote:

> On Thu, Jun 05, 2008 at 02:28:20PM -0700, bill fumerola wrote:
> > On Thu, Jun 05, 2008 at 07:26:00PM +0200, Mohacsi Janos wrote:
> > > for point-to-point links prefix longer than /64 was worked without any
> > > problem on Cisco boxes.
> >
> > for internal point-to-point links, using ospfv3 + link-local addresses
> > + /128s on loopbacks has worked well for me. for point-to-point on the
> > edge, i've used /64s down to /120s. depending on your IGP, using global
> > addresses on point-to-point may have its benefits.
>
> How does traceroute work when using link-local addressing on
> point-to-point links?

Very well. It will pick up the one the global IPv6 address of the box as 
a sourceaddress of ICMPv6 TTL exceeded. If you 
want make it detereministic set up unnumbered to ipv6 loopback. In case of 
cisco routers e.g.:

interface GigabitEthernet3/4
 mtu 9216
 ipv6 unnumbered Loopback0      <------
 ipv6 enable
 ipv6 ospf network point-to-point

Regards,

Janos Mohacsi
Network Engineer, Research Associate, Head of Network Planning and Projects
NIIF/HUNGARNET, HUNGARY
Key 70EF9882: DEC2 C685 1ED4 C95A 145F  4300 6F64 7B00 70EF 9882

>