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Re: [DNA] A comment on draft-pentland-dna-protocol3-00.txt

Brett,

I found this while digging into the DT mail archive. Erik educated me 
once with the following:

"Even if DHCP is used for address autoconfiguration, there is normally 
significant benefit of telling the hosts the on-link prefixes.

If the routers don't advertise any on-link prefixes, then the hosts will 
have to send all packets to a router (even when the destination is on 
the local link). RFC 2461 does have a redirect message which the routers 
can use in this case to tell a host "the destination is on link - at 
this L2 address". But for a normal broadcast medium, having the hosts 
know the on-link prefixes and using NS/NA to find the L2 addresses is 
more efficient."

However, it's still valid to have a network where the router advertises 
no prefix in the router advertisement but as pointed out above it is not 
an optimal way of configuring the network.

/Tero

Tero Kauppinen (JO/LMF) wrote:
> Hi Brett,
> 
> Hopefully this has not already been brought up in one of those mails on 
> the mailing list. I tried to quickly look through the issues in other 
> mails and the eye didn't catch this one.
> 
> We were discussing this on the design team mailing list sometime ago, 
> but I don't remember what was the conclusion. Anyway, the case when the 
> router is not advertising any prefixes, e.g. the case when stateful
> autoconfiguration is applied, is not clearly stated in the specification 
> how to proceed (i.e. obviously no landmark prefix can be picked, CPL 
> list can't be constructed). Or is it enough just to state the following?
> 
> 6.2.6.3  DNA and Statefully Configured Addresses
> 
> ...
>    signaling.  If, however, a non-DNA RA is received, the host SHOULD
>    use the DHCPv6 CONFIRM message as described in RFC 3315 [8] rather
>    than wait for additional RAs to perform CPL, since this will reduce
>    the amount of time required for the host to confirm whether or not it
>    has moved to a new link.
> 
> 
> /Tero