Big Temporary Networks
masatoshi-e at is.naist.jp
Mon Sep 17 01:03:29 UTC 2012
Masataka Ohta <mohta at necom830.hpcl.titech.ac.jp>:
>Nick Hilliard wrote:
>>> Thus, protocols heavily depending on broadcast/multicast, such
>>> as ND, will suffer.
>> ok, you've trolled me enough to ask why ND is worse than ARP on a wavelan
>> network - in your humble opinion?
>Because, with IPv4:
> 1) broadcast/multicast from a STA attacked to an AP is
> actually unicast to the AP and reliably received by the
> AP (and relayed unreliably to other STAs). That is, a
> broadcast ARP request from the STA to the AP is reliably
> received by the AP.
> 2) the AP knows MAC and IP addresses of STAs
> 3) ARP and DHCP replies are usually unicast
>ARP and DHCP usually work.
>For an unusual case of ARP for other STAs, collisions do
>increase initial latencies, but as refreshes are attempted
>several times, there will be no latter latencies.
>OTOH, IPv6 requires many multicast received by STAs: RA and NS
>for DAD, for example.
>Worse, minimum intervals of ND messages are often very large,
>which means a lot of delay occurs when a message is lost.
> Masataka Ohta
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