Re: [6lo] Fwd: New Version Notification for draft-toutain-6lo-local-extensions-00.txt

[Carsten Bormann <[e-mail]>]

On 01 Aug 2014, at 15:30, Pascal Thubert (pthubert) <[e-mail]> wrote:

> Dear all:
> 
> After careful thoughts on Laurent's work, I think we really could benefit from a 6lowpan 'routing dispatch' with a compression for the RPL option, routing headers, and whatever else might be needed to route the original packet or any individual fragment within the LLN, enable livelive (PRP), chaining (SFC), overlays (NVO3), or whatever else. 

Putting this kind of information at this point is a much better way than storing it in the flow label.
We tried to guess what might be needed with the mesh header in RFC 4944, but we failed.
YAGNI applies, and we couldn’t really guess the details right at the time anyway.

The main disadvantage of carrying sub-IP information around in the 6LoWPAN headers is that it is hard to move it over to the non-6lo world, say, Ethernet-style PLC encapsulation.  But that may not be a big problem, because IP-in-IP is much more tolerable in that world.  Also, the 802.3/802.1 world has its own stack of headers (VLAN tags with 802.1Q priority etc.), so there may be another way to handle this.  If that doesn’t work, there is always a label stack.

I’m not sure I understand (or agree with) all of the details in Laurent’s draft, but it sure serves as a wakeup call.

Grüße, Carsten