IPv6 RA vs DHCPv6 - The chosen one?

Michael Sinatra michael at rancid.berkeley.edu
Sat Dec 24 02:20:04 CST 2011


On 12/23/11 13:00, Masataka Ohta wrote:
> Tomas Podermanski wrote:
> 
>> It sounds good, but according to  RFC 6434 ( IPv6 Node Requirements)
>> SLAAC is required,
> 
> Not at all. SLAAC is required only if ND is supported, which
> is optional.
> 
> Note that ND works poorly over link layers such as 802.11
> where multicast is unreliable.
> 
>> but DHCPv6 is only optional.
> 
> DHCPv6 works over link layers with unreliable multicast
> better than ND.

You still need ND to provide the link-layer address resolution (i.e. the
IPv6 equivalent of ARP), even with DHCPv6.  Moreover, how do you come to
the conclusion that DHCPv6, which uses multicast for the solicitation,
is more reliable over links where multicast is unreliable?

FYI, I have been using SLAAC over 802.11 for many years, and have
supported large 802.11 installations with SLAAC and have never had a
problem related to "unreliable multicast" on that medium. Other
problems, yes.  But not that one.

michael



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