-----Original Message----- From: pch-b29aa8...@u-1.phicoh.com [mailto:pch-b29aa8...@u-1.phicoh.com] On Behalf Of Philip Homburg Sent: Monday, October 17, 2011 11:00 AM To: Hemant Singh (shemant) Cc: IPv6 WG Mailing List Subject: Re: FW: New Version Notification for draft-hsingh-6man-enhanced-dad-01.txt
>I think 20 bits should be already be more than enough. For simplicity, I would >just go for 64 bits. Appreciate the quick reply. Note BrianC already noted that 20 bits will not suffice by saying "It puts you into birthday-paradox territory on a LAN with a few hundred nodes.". His email is at the URL below. http://www.ietf.org/mail-archive/web/ipv6/current/msg14835.html We can go for a 62 bits long nonce in the Nonce Option. Can't pick 64 because the Nonce Option will then not end in an 8-byte boundary. See the details from RFC 3971 below. Regards, Hemant 5.3.2. Nonce Option The purpose of the Nonce option is to make sure that an advertisement is a fresh response to a solicitation sent earlier by the node. The format of this option is described in the following: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Nonce ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | . . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 14 Length The length of the option (including the Type, Length, and Nonce fields) in units of 8 octets. Nonce A field containing a random number selected by the sender of the solicitation message. The length of the random number MUST be at least 6 bytes. The length of the random number MUST be selected so that the length of the nonce option is a multiple of 8 octets. -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
