nanog mailing list archives

Re: IP4 address conservation method


From: Tore Anderson <tore () fud no>
Date: Fri, 07 Jun 2013 08:35:57 +0200

* Blake Hudson

One thing not mentioned so far in this discussion is using PPPoE or some
other tunnel/VPN technology for efficient IP utilization. The result
could be zero wasted IP addresses without the need to resort to
non-routable IP addresses in a customer's path (as the pdf suggested)
and without some of the quirkyness or vendor lock-in of using ip
unnumbered.

PPPoE (and other VPNs) have many of the same downsides as mentioned
above though, they require routing cost and increase the complexity of
the network. The question becomes which deployment has more cost: the
simple, yet wasteful, design or the efficient, but complex, design.

<shameless plug alert>

Or, simply just use IPv6, and use a stateless translation service
located in the core network to provide IPv4 connectivity to the public
Internet services.

This allows for 100% efficient utilisation of whatever IPv4 addresses
you have left - nothing needs to go to waste due to router interfaces,
subnet power of 2 overhead, internal servers/services that have no
Internet-available services, etc...all without requiring you to do
anything special on the server/application stacks to support it (like
set up tunnel endpoints), add dual-stack complexity into your network,
or introduce any form of stateful translation or VPN service into your
network.

Here's some more resources:

http://fud.no/talks/20130321-V6_World_Congress-The_Case_for_IPv6_Only_Data_Centres.pdf

http://tools.ietf.org/html/draft-anderson-siit-dc-00

In case you're interested in more, Ivan Pepelnjak and I will host a
(free) webinar about the approach next week. Feel free to join!

http://www.ipspace.net/IPv6-Only_Data_Centers

BTW: I hear Cisco has implemented support for this approach in their
latest AS1K code, although I haven't confirmed this myself yet.

Tore


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