> the introduction of IPv6 allows us to act as a greeenfield site regarding
> address allocation and routing - therefore, rather than have everything fragmented
> all over the place (....over 2k of routes once seen on internal routers!)
> ...
I think we take the opposite view - that we're putting an IPv6 overlay
on an existing infrastructure and it helps to align the numbering as
much as possible. (Currently we have about 700 IPv4 routes.)
> ... we
> use the SLA-ID to identity the network as follows
>
> XYYY
>
> where X is the VTP domain/campus park and YYY is the VLAN (we kept in 3 digit
> VLAN territory)
>
> by using the X designator, a section of the IPv6 space at that boundary cannot
> suddenly be in another routed domain...
So you have overlapping sets of 3-figure VLAN numbers? You don't carry
VLANs across domains?
My only caveat here is that a similar kind of functional component in
addressing was tried with NSAPs and never really worked well[0].
> i did look at doing it 'properly' with the VLAN etc being hex-encoded - ie non
> human readable (*) but there were complaints that IPv6 was already difficult
> enough..... by using trhe human-readable, our less techy people can read the
> address (yes yes) and see what VLAN they are on..or the system is on etc
Absolutely - KISS, or at least KIASAPBNSTPS.
> * of course, some people can do on the fly xlation in their h34ds ;-)
Those people will be the non-humans, right?
> PS as others have said - feel free to follow your own dreams...but I would
> say dont let your IPv6 space get fragged to death across the network.
We don't see any significant pressure on the memory in our routers from
700 routes and double that would still be insignificant - YMMV.[2]
> PPS I would also point you to these masterpieces:
> http://www.surfnet.nl/Documents/rapport_201104_IPv6_Deployment_In_Local_Area_Networks.pdf
> https://www.ripe.net/lir-services/training/material/IPv6-for-LIRs-Training-Course/IPv6_addr_plan4.pdf
Interesting, not least because the first one tells me there's still (as
at April '11) no one method of host configuration that works for
everything, except for SLAAC. At first glance excellent documents,
though.
Sam
[0] Different network topology, but may just be because NSAPs never
really worked well.
[1] Will be putting - I'm still not quite convinced that IPv6 is ready
for service and we still have a lot of management apps that need to be
updated or replaced.
[2] Just for interest, our oldest and smallest router has 16MB of
memory, some of which is reserved for the OS, but less than 2MB is used
and 9.5 MB is free. It has all 700 prefixes but it won't be running
IPv6 - it's too old to have been upgraded for the Y2K bug.
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
|