Re: [Roll] using the flow label instead of hop by hop

["Pascal Thubert (pthubert)" <[e-mail]>]

Hi Michael

At the time I wondered what sort of communication to the other side of the core was being envisioned in this thread.
If the end host wanted to use that flow label as a backchannel (or covert channel or an IPv6 version of the D-channel or whatever) 20 bits of data at a time, now, that would be a hack.
In any fashion, the flow label cannot be used to transport valuable information because it cannot be verified on the receiving side. Still, with the proposal, the root gets to see it, so for what that is worth it may use it.

The flow label is currently defined for the end host to interact with the core. Once the core is traversed, the value of the flow label is consumed. Thus it can be reset and reused.
Resetting the flow label for incoming packets at the root is a safe thing to do, there is no envisioned need to preserve the original flow label, and thus no envisioned need for IPinIP.

Cheers,

Pascal


-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On Behalf Of Michael Richardson
Sent: jeudi 25 octobre 2012 17:05
To: Philip Levis
Cc: Pascal Thubert (pthubert); [e-mail]
Subject: Re: [Roll] using the flow label instead of hop by hop


Philip Levis <[e-mail]> wrote:

    PL> What if an end-host outside the RPL instance wants to use a flow
    PL> label for its own purposes? It might think that a flow denotes a
    PL> stream of associated packets to a node within a RPL instance, not
    PL> the OF that instance happens to use.  

I presume that this end-host is interacting with the LLN in some way (or the question is irrelevant) When the packets arrive at the gateway, a 6in6 header is added.