I'd sure be interested in hearing what others in the WG think
on this issue.
I agree with Erik.
I see two alternatives:
1. ND proxy. Limited to single router, proxy from uplink to downlink. No need for loop detection.
2. Multilink subnet routing. Handles arbitrary topologies. Must handle loops.
publishing a specification for ND proxy with support for a restricted
topology (multiple routers) without handling loops is just
irresponsible.
In light of Pekka's suggested NDproxy caveats (e.g., put a warning label
on the box, expect users to correctly interpret livelock due to looping as
a configuration issue, etc.), I have to agree with this. I think the terminology
may be getting a bit confusing here as well. When we say: "ND proxy", or
"Multilink subnet router", we are really referring to a device that acts as an
L2 bridge in some instances and inspects/modifies/responds to L3 message
contents in other instances - some have even called this "L2.5", and I recall
seeing the term "Brouter" used in days gone by.
In any case, I really believe such devices will require mechanisms to support zero configuration and automatic topology discovery. A user should be able to just plug it in and have it work without needing a degree in network engineering to diagnose any number of esoteric problems that might crop up. This means that we need some form of loop prevention that is agile in terms of adapting to dynamic topology changes, doesn't unnecessarily disable interfaces as a means for loop prevention, and allows for neighbors to be reachable over possibly multiple interfaces.
In other words, we need something like the experimental protocols coming from the MANET wg (e.g., AODV, DSR, OLSR, TBRPF). Even better would be a unified mechanism that combines the best aspects of on-demand and reactive protocols.
Fred [EMAIL PROTECTED]
-------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
