Re: [Roll] how to solve flow from RPL-aware-leaf to non-RPL-aware-leaf

Michael Richardson <mcr+ietf@sandelman.ca> Mon, 22 February 2016 15:19 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Routing Over Low power and Lossy networks <roll@ietf.org>
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Date: Mon, 22 Feb 2016 10:19:53 -0500
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Subject: Re: [Roll] how to solve flow from RPL-aware-leaf to non-RPL-aware-leaf
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Michael Richardson <mcr+ietf@sandelman.ca> wrote:
    > In section 5.9 (Flow from RPL-aware-leaf to RPL-aware-leaf), an IPIP is
    > not necessary, since the receiving node is RPL aware, it can remove the
    > RPI.

    > In this case, however, the end-node is not RPI aware, so the 6LR3 needs
    > to remove the RPI.  In order for that to happen, the IPIP header needs
    > to be addressed to 6LR3, but 6LN doesn't have any idea what 6LR3's
    > address.

I wanted to add that the sending node has no way of knowing if it is
in situation 5.9 or situation 5.10, so absent some signaling that there are
no non-RPL aware nodes in the DAG, then sending nodes must assume that the
receiver is not-RPI aware.

An additional possible protocol action might be to signal in the DIOs that
that the RPL network is entirely RPL-aware.  This would/could get negated by
DAOs having a bit so indicate if each target address is RPI aware (i.e. if it
was learned from ND or via DAO).

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-