Subject: Comments on draft-ietf-6man-rpl-option-01

From: Suresh Krishnan <[email-masked]>
Date: Mon, 20 Dec 2010 19:10:50 -0500

Hi Authors,
   I went through draft-ietf-6man-rpl-option-01 and I had some comments.

* Section 2

This text is not consistent with the option type request in section 3

"and that ICMP errors return to the RPL Option source rather than ..."

The option type in section 3 (Top two bits 01) will not result in ICMPv6 
errors being sent. Is this really your intent?

* Section 3

This option is missing an alignment requirement. Given that the 
SenderRank is a 16 bit number, I would recommend having an alignment 
requirement of 2n.

* Section 5

I don't think this text is consistent with the tunneling behavior 
specified earlier in the document. Especially this text

"RPL Border Routers MUST remove
    the RPL Option from the datagram and update the IPv6 Payload Length
    field accordingly."

does not agree with the tunneling behavior. If I understand correctly, 
the RPL option will be included after the outer IPv6 header that 
encapsulates the IPv6 datagram to be forwarded to the outside world. All 
the RPL border router needs to do is to process the outer IPv6 header 
and HBH options header and remove them before forwarding it to the 
outside world. Is my understanding incorrect?

Cheers
Suresh