Hi, My understanding of the document is the same as that of Josh, except for this thing that was left out
if L=1 and Lifetime=0 remove the prefix from the prefix list (switch from talking directly to talking through the router) Cheers Suresh -----Original Message----- From: Josh Littlefield [mailto:[EMAIL PROTECTED] Sent: Wed 5/12/2007 2:08 PM To: Hemant Singh (shemant) Cc: Suresh Krishnan; [EMAIL PROTECTED]; IETF IPv6 Mailing List Subject: Re: Here is the reference to 6.3.4 text that is ambigious text It is not crystal clear, but my impression is that this paragraph is saying: Default sending behavior is send to default router. Reception of L=1 signals on-link (can use ND to send directly) Reception of L=0 is no-op. Because L=0 is no-op, if one considered the prefix on-link due to prior L=1, then prefix is still on-link. If one did not consider the prefix on-linke due to prior L=1, then retain default behavior. It might be clearer to have said that default assumption is that all prefixes are off-link, and this means send to default router. Only reception of L=1 can change that for any specific prefix. A prefix with L=0 does not change off-link, or on-link status of prefix, and is the same as omitting the prefix entirely from the RA, from the point of view of on-link determination. Hemant Singh (shemant) wrote: > > The summary from this section snipped from 6.3.4 of RFC 4861 is saying > no on-ink information does not mean off-link. So why is the text is > red where is says, send traffic to default router being said because > the text in red signals off-link behavior. Why is this paragraph not > ambiguous? > > > Prefix Information options that have the "on-link" (L) flag set > indicate a prefix identifying a range of addresses that should be > considered on-link. Note, however, that a Prefix Information option > with the on-link flag set to zero conveys no information concerning > on-link determination and MUST NOT be interpreted to mean that > addresses covered by the prefix are off-link. The only way to cancel > a previous on-link indication is to advertise that prefix with the > L-bit set and the Lifetime set to zero. The default behavior (see > Section 5.2) when sending a packet to an address for which no > information is known about the on-link status of the address is to > forward the packet to a default router; the reception of a Prefix > Information option with the "on-link" (L) flag set to zero does not > change this behavior. The reasons for an address being treated as > on-link is specified in the definition of "on-link" in Section 2.1. > Prefixes with the on-link flag set to zero would normally have the > autonomous flag set and be used by [ADDRCONF]. > > Hemant > > ------------------------------------------------------------------------ > > -------------------------------------------------------------------- > IETF IPv6 working group mailing list > ipv6@ietf.org > Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 > -------------------------------------------------------------------- > -- ===================================================================== Josh Littlefield Cisco Systems, Inc. [EMAIL PROTECTED] 1414 Massachusetts Avenue tel: 978-936-1379 fax: 978-936-2226 Boxborough, MA 01719-2205 -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
