Tassos, From: Tassos Chatzithomaoglou [mailto:[email protected]] Sent: Friday, October 14, 2011 6:29 PM To: Hemant Singh (shemant) Cc: IPv6 WG Mailing List Subject: Re: FW: New Version Notification for draft-hsingh-6man-enhanced-dad-01.txt
>I was wondering...wouldn't the flow label be a "better" field for storing this >random number? >If i remember correctly, early drafts of RPL were using it for loop detection >(ok, in a very different way), although in the later ones a new option was >chosen. >Sure, RFC 3697 is very strict on its specification, sure SEND already uses the >Nonce option, but since we are talking about ND only (=before any real src/dst >flow) i would like to know the >rationale behind of this decision; choosing an >extra option instead of a mandatory -useless until recently- field. Maybe >then, all ND messages could be supported (less impact on memory?). >I may have missed some talks about this in the past (or maybe i'm talking >nonsense :-[ ), so please forgive me if this is the case. No forgiveness needed ☺. You have been a great reviewer for lot of documents! The flow label was the first field I and another colleague of mine at Cisco thought of. However yet another colleague of mine shot down the use of Flow Label with the following comments in double quotes. “Using the flow label for this is likely to be highly controversial. I can already hear people claiming it's not a "flow", etc.” The flow label has another nuance. It's a 20-bit field and thus a nonce generated with such number of bits has one in a million chance of a duplicate. The community may prefer at least a 32-bit nonce or higher. That is why I decided to just use the Nonce Option from SEND in RFC 3971. Thus can we move away from the Flow Label and use the Nonce Option from SEND? Thanks, Hemant -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
