Re: Using /126 for IPv6 router links

[David Barak <thegameiam () yahoo com>]

----- Original Message ----
From: Dale W. Carder dwcarder () wisc edu
On Jan 27, 2010, at 3:19 PM, Igor Gashinsky wrote:
> you face 2 major issues with not using /127 for
> PtP-type circuits:
>
> > 1) ping-ponging of packets on Sonet/SDH links

> Following this, IPv4 /30 would have the same problem vs /31?

No, because IPv4 has the concept of Broadcast, while IPv6 does not.  Remotely sending packets to an IPv4 broadcast 
address is a "directed broadcast" and that is generally denied by default on modern kit.  

> > 2) ping sweep of death
>
> >     Take the same assumption for addressing as above, and now ping
> >     sweep 2001:db8::/64... if the link is ethernet, well, hope you
> >     didn't have any important arp entries that the router actually
>  >   needed to learn.

> Wouldn't this affect *all* /64's configured on a router, not
> just point to point links?  Time for glean rate limiting.

This is, of course, one of the reasons why some of us didn't like the ultra-mega-mega ranges used to address handfuls 
of hosts, but that ship sailed long ago.  

David Barak
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