----- Original Message ----- From: Masataka Ohta <[EMAIL PROTECTED]> Date: Wednesday, November 10, 2004 2:50 am Subject: Re: Why, technically, MIP and IPv6 can't be deployed
> Francis Dupont wrote: > > > > Could you describe why exactly IPv6 can't run on the (layer > 2?) WLAN > > > infrastructure? > > > > That ND extensively, without any valid reason to do so, use > > multicast, which is not acknowledged at WLAN L2, means IPv6 > > or its ND is unreliable over congested WLAN. If multicast > > ND packet is lost by congestion, it is not retransmitted by L2. > > > > => Masataka san, your argument is right (I saw 40% lost rate > > on multicast over IEEE 802.11b) but it applies to IPv4 (ARP > > uses broadcast) too... > > Yes, it does, but not so badly. > > ARP actually use broadcast for request but not for reply. ND uses unicast for replies (Router Discovery may not though). > Moreover, ARP request from terminals to base stations, which > are often routers, are unicast at lower L2. Same with ND. Same with _any_ MAC unicast with toDS=1... > So, over WLAN, ARP works a lot better than ND. It should > also be noted that, with IPv4, it is natural to have link > specific adaptation mechanism for each different link type > that it is perfectly fine to have IP over WLAN which is > different from IP over Ether. Your premises are incorrect, the comparisons you are using are invalid. > On the other hand, ND, an attempt to have a universal > adaptation mechanism ignoring link specific properties, > which contradicts with the very basic reason to have > "adaptation", is a total failure. Really, so does ARP, except where it's not supported, and requires servers. > It should be noted that MIPv6 is hopelessly tainted by ND. I'l take hopeless ND taints any day. The ND architecture as part of IPv6 (rather than the link-layer) allows L3 neighbour security mechanisms to be implemented once in IP. I think that retransmission timers, and ordering of messages in ND can be altered. The insecurity of ARP cannot. Which do we need for the future 10-15 years of the Internet? Greg _______________________________________________ Ietf mailing list [EMAIL PROTECTED] https://www1.ietf.org/mailman/listinfo/ietf
