8. Unit Networks

Each unit (that is, a department, college, PPH) shall be allocated one /56 network and no more. It is expected, and hoped, that this will be the only network ever allocated to the unit. A multi-site unit will be expected to use this allocation for all sites. Routing can be hosted within the university backbone by OUCS, or within the unit, in the same way as the current IPv4 system allows.

According to the standard model of using /64 subnets, each unit will have 256 subnets available for use within their site(s). An example of the use of such subnets might be the common present day division of staff, students, libraries and so on. This might extend to, say, research groups in the future.

It is the opinion of some that layer 3 functionality will get pushed down to the edge of the network, over the next 10-15 years, meaning it becomes more common to have many routing devices within a site. This would allow for the example of a research group being given their own /64 subnet.

/56 Base Prefix/64 Extension PrefixRole
2001:0630:0441:00 00 Unit A's First Subnet
2001:0630:0441:00 ff Unit A's Last Subnet
2001:0630:0441:01 00 Unit B's First Subnet
2001:0630:0441:01 ff Unit B's Last Subnet
2001:0630:0441:02 - Next Unit
2001:0630:0441:ff - 256th Unit
2001:0630:0442:xx - 256 More Units
2001:0630:0443:xx - 256 More Units

This initial model supports up to 768 units within the collegiate University. Networks will be allocated to units in strict sequential order as they are requested. The last two nibbles of the /56 network will not encode any special meaning (though the 0441 - 0443 denotes this is a unit prefix, at least).

Although a complete /56 will be allocated and routed via a linknet to a unit on request, if annexe sites are in use it might be appropriate to allocate a /60 section to each site and route that locally, supporting up to 16 sites or fewer if additional networks are required at one site.

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