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Re: DHCP vs. RA... again.



Tony - the network operators I was referring to are interested in DHCP-only operation because, in their deployment experience, RAs have proven problematic. I understand the model you are referring to, but that model comes from a different set of network operators.

We can certainly argue about whether RAs are fundamentally more problematic than DHCP and whether what we need to do is fix ND or extend DHCP; what I am reporting is what these operators have told me based on hands-on experience with deployed networks.

- Ralph

On Aug 3, 2007, at Aug 3, 2007,4:36 PM, Tony Hain wrote:

james woodyatt wrote:
...
Are the network operators who are expressing "the specific
requirement" that their network not "depend on RA" willing to accept
that they still need RA to signal nodes that DHCP is required for
obtaining prefix information and default router addresses?

Or, do they want RA deprecated completely?  If they do, then I
wouldn't like that.


To shorten a long debate, the deployment models for not using RA are
fundamentally broken to start with. They are based on the concept that an RA would result in a shared prefix between customers, because they are not taking the step to do L2 isolation between the aggregation point and the customer base. On top of that the security model is wrapped up in using DHCP as their trust anchor (never mind that spoofing a mac blows this away).

It is perfectly fine for the DHC wg to provide the tools for these operators to deploy the way they want to. It is not reasonable for those operators to drive their broken deployment model on the rest of the world by insisting that DHCP is 'the only tool'. For them the RA should indicate 'use DHCP', while for the rest of the world the RA should indicate the DNS server so
that DHCP is not required.

Tony