nanog mailing list archives

Re: turning on comcast v6


From: Ryan Harden <hardenrm () uchicago edu>
Date: Mon, 30 Dec 2013 19:20:25 +0000

On Dec 30, 2013, at 12:58 PM, Lee Howard <Lee () asgard org> wrote:



'Rewrite all of your tools and change your long standing business
practices¹ is a very large barrier to entry to IPv6. If adding gateway as
an optional field will help people get over that barrier, why not add it?
Sure it doesn¹t fit into the ³IPv6 way,² but bean counters don¹t care
much for that when you have to ask for developer time to rewrite
everything.


Well, the tools have to be rewritten to support IPv6 fields, sockets, and
structures anyway.  However, there's a difference between, "Make sure you
call IP family agnostic libraries and increase field sizes, then let it
run" and "Rebuild your network security."  DHCP+RA just works in most
networks; this is a use case where it could be made to work, but only by
changing the network.

Updating tools to add a box for IPv6 fields and tweaking the backend to generate a config file for DHCPv6 which is very 
similar to DHCP(for v4) is a lot different/easier than having to rewrite and/or split your backend to generate output 
in a completely different format. However, I'm not as familiar with RADVD as I am with isc-dhcpd so that might be a bad 
argument.

And you don't have to support IPv6 from top to bottom to roll out IPv6 to users. So rewriting for socket support isn't 
necessary day one. You can route IPv6 for users so they can reach the IPv6 world quickly, then add local services as 
time/money allows. The biggest driver for IPv6 will be external resources available only via IPv6, not local. (Of 
course this is from the point of view where your business' primary service isn't outward facing resources.)

I'm sure DHCP+RA works for most, but there are IPv4 shops who swear by fully dynamic DHCP, some who do 
DHCP-Reservations, and some who go static only. Just like some shops are EIGRP, some OSPF, and some ISIS. IMO IPv6 
needs to be flexible enough to handle the fact that not everyone builds identical architectures nor do they have the 
exact same needs. Being able to use DHCPv6+RA, RA only, or DHCPv6 only should all be viable options. Forcing everyone 
down the same path will just lead to stupid proprietary solutions to a problem that shouldn't exist in the first place.

/Ryan

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