[Lincoln LUG] IPv6 followup and future topics

[Terry Froy]

> Thanks for a great talk yesterday - it was all very interesting stuff!

Hi Graham,

I'm glad you found it so!

> > * How does IPv6 subnetting work ?
> > 
> > Someone (sorry, I forgot your name!) asked me how subnetting works in IPv6;
> > the following RIPE CIDR charts explain that quite well:
> > 
> > http://www.ripe.net/lir-services/training/material/LIR-Training-Course/LIR-Training-Handbook-Appendices/CIDR-Chart-IPv4.pdf
> > http://www.ripe.net/lir-services/training/material/LIR-Training-Course/LIR-Training-Handbook-Appendices/CIDR-Chart-IPv6.pdf
> > 
> > If anyone wants a handy pocket-sized copy of these charts, as my business is a
> > RIPE member, RIPE will supply these to us FOC and I am happy to give them to
> > anyone who wants them at a future LUG meeting.
>
> It was me who asked this - thanks for your answers, and those charts look handy
> - it's relatively easy to calculate subnetting for IPv4 mentally, but the
> numbers are a bit too big with IPv6!

The easiest way to assign IPv6 is to forget everything you know about IPv4 subnetting and do the following:

* For every VLAN (or Ethernet segment), assign a single /64.
* For a router which is a participating within an IGP, assign a /128 (single IPv6 addy) for use as a loopback.
* For point-to-point links, a /64 is fine but you may wish to assign a /96 or a /120 as routes with a prefixlength divisible by 8 are 'easier' on routers.

That covers IPv6 assignment for end users.

Typically an ISP will assign a /64 for use on the customers' WAN-facing interface and then route a /48 down the link for use by the customer; whilst RIPE specify the maximum size you can assign an End User is a /48, it is acceptable for an ISP to assign a /56 (256 usable /64s) or even a /60 (16 usable /64s).

We also have a number of 'special purpose' assignments such as a /96 for NAT64 - http://en.wikipedia.org/wiki/NAT64 - and one of my pet projects is on that topic but I fear it would be far too specialist to be useful as a LUG talk.

> > We also do a lot with FreeBSD for reasons which I'd be happy to elaborate on
> > when Tom does his 'Why Linux sucks!' presentation ;-)
>
> This sounds interesting - personally I'm not aware of what GNU/Linux gets wrong,
> so it'd be interesting to see these perspectives.

It isn't so much as what GNU/Linux gets wrong - it is more about what other OSes do better.

For example, we terminate all of our ADSL/FTTC users' PPP sessions on FreeBSD boxes because the FreeBSD kernel does 100% of PPP in kernel-space whereas Linux splits it unevenly across kernel and user-space components; while this is fine for a home user terminating a single ADSL or FTTC line, it doesn't scale at the ISP-side where you may be terminating hundreds or even thousands of PPP sessions which could each be 40Mbit/s.

> > I would also be happy to co-ordinate PGP key signing parties at future
> > meetings - http://en.wikipedia.org/wiki/Key_signing_party - for those who
> > don't know what I am talking about.
>
> This sounds like a good idea!

At least I will have at least one key to sign ;-)

> > ... and an IRC channel would also be very nice... do we want one as I can sort
> > that rather easily ?
>
> That would be good. I've been idling in #lincslug on Freenode for a few weeks or
> months, and I guess this channel belongs to the defunct Lincolnshire LUG. It
> would be nice for there to be a more active IRC channel.

I agree entirely.

Something to sort next week methinks...

Regards,
Terry