On 17/03/2014 13:08, Ewan MacMahon wrote:
>> -----Original Message-----
>> From: Testbed Support for GridPP member institutes [mailto:TB-
>> [log in to unmask]] On Behalf Of Alessandra Forti
>> Sent: 17 March 2014 12:40
>> To: [log in to unmask]
>> Subject: Re: IPv6 addresses
>>
>> /48 is what NNW asked JANET for us (although I don't think we actually
>> need it).
>>
> I think a /56 a good fit for most 'things', where a thing is some sort of
> single logical deployment - so a grid cluster would be one, but a department
> or college might also be one. By-the-by, the space allocated to my domestic
> ADSL is also a /56, despite there being a total of something like four IPv6
> capable devices hanging off it. I'm not sure what I'd do with a /48 in a
> single deployment, but it would be a little tight for a whole university.
Indeed - I should have added in my previous mail that Cambridge will
allocate addresses in /56 units.
John
>
>> In any case JANET bounced us back to the University which was
>> given a /48 for the whole campus and now I'm discussing with them how to
>> proceed. They have the same problem as QMUL and apparently Oxford had,
>> /48 is too small for the whole Uni and they need to renegotiate either
>> with JANET like Oxford has done, or like QMUL with RIPE.
>>
> According to:
> http://www.oucs.ox.ac.uk/network/addresses/ipv6/index.xml?ID=history
> the expansion of the Oxford space was by 'An application was made through
> JANET to RIPE'. One of the intended advantages of IPv6 is to simplify the
> routing tables on core routers by keeping things in coherent blocks, so
> rather than having a long list of small allocations, you can route whole
> blocks at a time, so e.g. external routers would be able to route traffic
> onto janet with a single entry, rather than having a list of the form
> "Oxford's allocation should be routed to janet, Cambridge's allocation
> should be routed to janet, Manchester's allocation should be routed to
> janet, etc.". Where you want your address range to be is therefore dependent
> on how you expect your routing to be done - if you expect traffic to come
> to you university edge/core routers and then on to you, then you want a
> range within the University's overall one. If you expect to have a separate
> parallel connection to janet, then you'd want a separate address range, not
> a subnet of the university space.
>
> Ewan
>
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