-----Original Message----- From: Jared Mauch [mailto:[email protected]] Sent: Sunday, August 15, 2010 9:07 PM To: Hemant Singh (shemant) Cc: Randy Bush; ipv6 deployment prevention; Wes Beebee (wbeebee) Subject: Re: Router redirects in Node Requirements document
>Oh my. >So, hosts shouldn't have to know anything about their environment anymore and this is just proxy-arp & redirects all over again? Not quite. The cable deployment I gave a use case for Redirect with, has hosts that know their traffic has to be sent to the default router. I also said, the cable deployment has hosts as always off-link to each other - if you are my neighbor, then your PC phone call talks to my PC phone call by sending traffic to the CMTS. Thus, the hosts completely know what their environment is. >Do you know what impact that has on IOS based devices? I suspect you've not seen the operational impact as a result of such items, otherwise you would understand how poorly vendors actually implement >these features for the operators. (Hence me raising the DoS issue). At least the high-end Cisco CMTS routers (ubr10000) I develop code for has rate-limiting for any DoS issue. Other Cisco routers will also have a generic rate limiting that will limit the Redirect DoS too. >Even with your aforementioned rate-limit items, this would possibly cause HA issues with switchover should a prefix/next-hop change, or a router fail. In my cable use case for Redirect, a RP card switchover still has the CMTS pointing the hosts in the downstream to the same prefix and next-hop. Anyway, I am not sure how HA and switchover has any impact on ND Redirect. We need a more specific case by case evaluation and see what problems do we have with Redirect. >Is there a legitimate operational reason a host should not know the subnet length it sits on? Another reason is if both the ND RA and DHCPv6 send prefix length's what if the information from two sources is different? One can fat-finger a DHCPv6 server configuration or the router IPv6 ND RA configuration. Who wins? Hemant -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
