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Jump to: Scheme details, VLANs 1-999, VLANs 1000-4094

VLANs using IEEE 802.1Q are given tags/IDs between 1 and 4094.  These tags can be used on links between the University Data Network (UDN - the University backbone network) and institutional networks and must match at both ends.

Care must be taken by network administrators to ensure that the IDs used for purely internal networks within their institutions (or the UDN itself), that do not need to pass across these links, do not clash with numbers which may be used for VLANs between networks (in particular, the UDN and an institution).

Whilst the distinction is only important if an institutional network is importing or exporting a VLAN, institutions should bear in mind that even if they have no intention of importing or exporting VLANs now, that may change in future.  Institutions are therefore recommended to allocate VLAN numbers based on the scheme to avoid future renumbering problems.

Scheme details

Ranges of numbers are allocated for different purposes:

Status Allocated by Use
Reserved UIS Reserved at the present time and must not be used.
Global UIS Globally used across the UDN.
Local UIS Local to an institutional network for UIS-supplied local services (e.g. the "inside" VLANs from a Managed Firewall).  This is to allow ID re-use across the network, where VLAN IDs do not need to touch the UDN backbone.
Internal Institution Within an institutional network, avoiding clashes with UIS-allocated IDs.

The tables below show which numbers are allocated to each of these categories.

VLANs 1-999

For tags in the form x | yz (1-999), a fairly complex scheme is used due to historical developments and configurations in place, prior to it being determined:

x | yz x00 x01 x02-x09 x10-x89 x90-x99
0yz - Internal Internal Internal Internal
1yz Internal Internal Internal Global Internal
2yz Reserved Reserved Global Global Internal
3yz Reserved Reserved Global Global Internal
4yz Reserved Reserved Global Global Internal
5yz Reserved Reserved Global Global Internal
6yz Reserved Reserved Global Global Internal
7yz Reserved Reserved Global Global Internal
8yz Reserved Reserved Global Global Internal
9yz Reserved Reserved Global Global Internal

VLANs 1000-4094

For VLAN numbers of 1000 and above, a much simpler scheme is in use:

802.1Q VLAN ID Designation
1000-1999 Internal
2000-3999 Global
4000-4094 Local

Last updated: 11th July 2024