[VoiceOps] IPV6
Alex Balashov
abalashov at evaristesys.com
Sun Oct 25 05:12:47 EDT 2009
Thank you, Dan. This is very helpful information.
Dan White wrote:
> On 21/10/09 13:47 -0400, Alex Balashov wrote:
>> It's certainly shorter. The issue is that it takes more effort and
>> time mentally to compute contiguity, subnet boundaries, etc. because
>> the numbers involved are not base 10.
>
> That's highly debatable, since it's base 16 and generally makes it simple
> to do subnetting.
>
>> Being a systems programmer by trade, I have little difficulty
>> counting in hex. It's just harder than counting in base 10,
>> especially for people who aren't similarly disposed. And
>> contractions do make it difficult to read.
>
> Service providers get allocated a /32 (unless they can justify a bigger
> block). That means that the ISP is generally subnetted on the 4th byte
> (or 8th nibble - leading zeros are removed). e.g.:
>
> 2610:b8::/32
>
> ISPs are expected to assign a /48 (6th byte):
>
> 2610:b8:1::/48
>
> or a /56 (7th byte):
>
> 2610:b8:1:2:/56
>
> to customers. ISPs don't care how addressing happens after that.
> As a provider you deal in subnets, not addresses (generally speaking).
>
> End users/network operators are expected to subnet on the /64 boundary (8th
> byte):
>
> 2610:b8:1:302::/64
>
> and depending on deployment, can leave address assignment up to
> auto configuration, which is where you get the really ugly looking
> addresses:
>
> 2610:b8:1:302:215:c5ff:fef1:8be1/64
>
> or you can use DHCPv6 or statically assign, like you do today with IPv4 -
> except that you have the hex (0-f) issue as you've noted.
>
> Other than that, there's really no *counting* involved in IPv6. There's
> nothing that says you have to assign your static addresses incrementally -
> you can, for instance, match the last octet of your IPv4 address with the
> last byte of your IPv6 address, which is what I prefer and doesn't get too
> bad:
>
> 2610:b8:1:302::1/64
> 2610:b8:1:302::254/64
> etc.
>
>> I do think that's one of the major barriers to the adoption of IPv6 in
>> a commonsensical, pedestrian way. Nobody is against bigger address
>> space, increased security, more interface autoconfiguration, etc. I
>> think they just look at the addresses and go, "Uh, I don't want to
>> read THAT..."
>
> I would be very surprised if this was a significant barrier.
>
>> Moving the transport core of a service provider to IPv6 is not so
>> difficult. But taking advantage of all the benefits you cite
>> requires that users be on IPv6 too, which is far from always a viable
>> state of affairs at this point. It's more likely if you're a CLEC or
>> ISP and control the network end-to-end to the customer edge, but
>> nearly impossible if you're an ITSP without facilities affinity.
>
> It's not so impossible if you view IPv6 as an added service, rather than a
> replacement for IPv4. Dual-stacking solves the chicken-and-egg problem of
> who converts first, and being able to support IPv4 and IPv6 simultaneously.
>
--
Alex Balashov - Principal
Evariste Systems
Web : http://www.evaristesys.com/
Tel : (+1) (678) 954-0670
Direct : (+1) (678) 954-0671
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