From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [PATCH v2] bonding: send IPv6 neighbor advertisement on failover Date: Fri, 10 Oct 2008 12:29:06 -0400 Message-ID: <48EF82D2.6030008@hp.com> References: <29444.1223654036@death.nxdomain.ibm.com> <48EF7CFF.4050405@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Jay Vosburgh , David Stevens , Alex Sidorenko , David Miller , Simon Horman , "netdev@vger.kernel.org" , netdev-owner@vger.kernel.org, YOSHIFUJI Hideaki To: Brian Haley Return-path: Received: from g1t0029.austin.hp.com ([15.216.28.36]:8922 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761572AbYJJQ3J (ORCPT ); Fri, 10 Oct 2008 12:29:09 -0400 In-Reply-To: <48EF7CFF.4050405@hp.com> Sender: netdev-owner@vger.kernel.org List-ID: Brian Haley wrote: > Jay Vosburgh wrote: >> As a semi-related question, what does IPv6 do if it receives a >> gratutitous NA, and finds a duplicate? > > If a node has an IPv6 neighbor entry and receives an unsolicited NA it > will change it's state to stale, forcing a re-lookup on the next > transmit. An un-solicited NA will change the state to reachable. ^^^^^^^^^^^^ You probably meant to say "solicited". Unsolicited NAs can only change the state to STALE. Also, the re-lookup will happen on a delay after the transmit. -vlad > >> I agree that doing DAD would update the switches, peers, etc, >> but, if I'm reading the IPv6 code correctly, the delay between probes is >> one second (nd_tbl.retrans_time), and it looks like there's an initial >> delay of up to 1 second as well (in addrconf_dad_kick, the >> rtr_solicit_delay). For failover purposes, we want to issue the >> gratuitous ARP or NA packets immediately with a minimal delay between >> probes. > > Right, and since a bond failover event should be rare, I think sending > the NA immediately is OK. All those random delays are meant to cover > the case, for example, when a router sends an advertisement with a new > prefix - you don't want everyone that receives it to do DAD immediately > since it could overwhelm the network. > > -Brian > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >