Hi Masataka,
On Tue, 8 Jun 2004, Masataka Ohta wrote: > Dear all; > > The problem is rather generic than DNS configuration. But... > > I know ND is wrong. That is, I know it is wrong to have generic > link protocols ignoring link specific properties and has been > pondering on how such protocols suffer. I think ND is not wrong. There is a clear need for better support to discover the link parameters, but it is necessary for mostly to the routing protocols. > > I just recently noticed that WLAN (802.11*) is not very good at > supporting ND (nor DHCP nor any broadcast/multicast protocol). > > Because WLAN use CSMA/CA, it needs ACK for reliable transmission > by confirming that each packet reaches its destination without > collision. > > However, with broadcast/multicast packets, there is no ACK for > an obvious reason. The IPv4 ARP is not better either, as you found. I think the WLAN should be improved some way to support multicast in some form. > > If WLAN is lightly loaded, it is not a serious problem. > > However, if WLAN is heavily loaded, ND (and DHCP and any broadcast/ > multicast protocol) works poorly. Note that MIPv6 works poorly > too. > > Still, management beacon frames are transmitted frequently > and expected to carry information in a long run. > > So, it is possible to piggyback broadcast/multicast part > of address resolution and autoconfiguration (maybe and > routing) in reserved fields of beacon frames. I think autoconfiguration can be treated differently, than address resolution. ND as stand for "Neighbour" Discovery is a very good improvement to ARP and transport specific things... Of course ND can get into trouble if no reply for ND requests (with soliticited node multicast address)... > > Though it is possible to use some data frame frequently > transmitted like beacon frams, it make the already congested > WLAN worse. > > Anyway, the fundamental mistake is to try not to have link > specific ways to perform address resolution and autoconfiguration. > > DHCP simply needs link specific ways of DHCP discover. > > ND needs, IMHO, a lot more. What do you think? > > Note that modifying WLAN protocol to use PIFS is not enough > unless combined with frequent transmission. I agree. Janos Mohacsi Network Engineer, Research Associate NIIF/HUNGARNET, HUNGARY Key 00F9AF98: 8645 1312 D249 471B DBAE 21A2 9F52 0D1F 00F9 AF98 -------------------------------------------------------------------- IETF IPv6 working group mailing list [EMAIL PROTECTED] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------