Subject: Re: nonexisting destination on p2p link

From: [email-masked]
Date: Fri, 27 Apr 2001 09:52:52 -0400 (EDT)

> >> case 1: consider link local address (La and Lb).
> >> 
> >>         A (La) --- (Lb) B
> >> 
> >> A has fe80::/10 (or fe80::/64 depending on your implementation)
> >> route pointed to the p2p link.  if A emits a packet with Lx (!= Lb) as a
> >> destination, it will reach B.  then B forwards it back to A.  then A forwards
> >> it back to B, ... until hoplimit field goes 0.  also, they would emit
> >> ICMPv6 redirect to the peer, since the packet gets forwarded back again to the
> >> incoming interface.
> >Well if Lx is link-local, it should not bie forwarded at all ?
> 
> 	in the existing RFCs, there's no wording that forbids forwarding
> 	packets to link local address, **given that we forward it back to the
> 	same link**.  A and B are forwarding packets back to the same link.
> 
> 	we cannot forward packets with linklocal address across different
> 	links.  this part is clear but we are not talking about this.

In the case of link-local addresses, I think that the packet should
only be  forwarded once across the p2p link- when the hop limit goes
below 255, it shouldn't get forwarded back?

However, I think the bouncing-back-and-forth situation could still
occur if there were 2 routers connected by a p2p link, each advertising
its own onlink prefix for the link, e.g., R1 advertising P1::/64, R2 
advertising P2::/64, and then R2 sends a packet to ip6_dst  P1::1
to be forwarded by R1..

--Sowmini
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