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RFC 5375: IPv6 Unicast Address Assignment Considerations

By stretch | Thursday, December 4, 2008 at 7:46 a.m. UTC

Here's a great example of what I wrote about just a few days ago. A new RFC released today, RFC 5375, provides some very practical guidelines on IPv6 address planning. In it, you'll find nine pages of discussion followed by two solid case studies and some additional considerations regarding non-/64 subnets.

Some highlights:

  • As you might expect, IPv6 address allocation is very similar to IPv4, but without nearly so much emphasis on address space conservation.
  • /64 subnets are a good idea, even for point-to-point links.
  • /64 subnets are virtually unlimited, so host subnetting isn't nearly as granular as with IPv4.
  • Unique Local Addresses (ULAs) introduce a new aspect of address assignment, which allow RFC 1918-like private addressing in parallel to global addresses.

Well worth the read. Also, if you're interested in keeping up on new RFCs as they're released, I recommend subscribing to the dedicated RSS feed.

Posted in IPv6, News


December 4, 2008 at 8:38 p.m. UTC

You can also subscribe to the RFC Editor's rfc-dist mailing list for email notifications to be sent to you. See for more details.

Grant. . . .

Justin G. Mitchell
December 5, 2008 at 12:21 p.m. UTC

Good stuff, but how many organizations are actually using IPv6? I know it was only recently a few of the root DNS servers began supporting IPv6 requests. I'm pretty sure most consumer devices don't support it and I have yet to step into a business that is actively using it.

To me it is one of those great technologies most people don't know about and honestly don't want to learn about. While most advanced networkers probably don't mind, the systems people I know would freak out when confronted with an IPv6 address.

M. Moradian
December 5, 2008 at 9:38 p.m. UTC

I agree with you, "Justin G. Mitchell". You are right. I think IPv6 is also designed to make some places more secure just because others do not care. I mean that if you don't have an IPv6 address and also your ISP (or telecom infrastructure) does not support IPv6, then there would be more secured devices that use IPv6 than the rest of the world which use IPv4, and the reason is that you can not address them. For a moment you can think that you are the only one lost in a country like China which you don't understand their language and that is your problem and their advantage.

Also thank you (the poster) for you post (and information), especially the RSS feed section.

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