skip to primary navigationskip to content
 

VLAN numbering

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 Cambridge University Data Network (CUDN - 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 CUDN 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 CUDN 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:

Reserved Reserved at the present time and must not be used.
Global Allocated by UIS Networks for global use across the CUDN; institutions must not allocate these numbers to their own VLANs.
Local Allocated for use within and by an institution without danger of clashing with numbers used by VLANs used globally across the CUDN.

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:

x \ yzx00x01x02-x09x10-x79x80-x89x90-x99
0yz - Local Local Local Local Local
1yz Local Local Local Global Global Local
2yz Reserved Reserved Global Global Global Local
3yz Reserved Reserved Global Global Global Local
4yz Reserved Reserved Global Global Global Local
5yz Reserved Reserved Global Global Global Local
6yz Reserved Reserved Global Global Global Local
7yz Reserved Reserved Global Global Global Local
8yz Reserved Reserved Global Global Global Local
9yz Reserved Reserved Global Global Global Local

The above scheme was modified during July-September 2016 with three main changes:

  • {2-9}0{2-9} (i.e. 202-209, 302-309, etc.) - from Reserved to Global status
  • {1-9}8{0-9} (i.e. 180-189, 280-289, etc.) - from Reserved to Global status
  • 2-99 - from Global to Local status

VLANs 1000-4094

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

1000-1999 Local
2000-3999 Global
4000-4094 Local

Last updated: 29 September 2016

Contact

If you have any enquiries regarding UIS network services, or other University network topics, please send an email to:

UIS Service Desk


  Phone padded  01223 332999

UIS bITe-size bulletin


A regular newsletter aimed at the University's IT community, highlighting service and project news from UIS.

Sign up >  |  Back issues

UIS Service Status

Phone padded  Service status line: (01223) 463085
Website padded  Sign up for SMS/email status alerts

RSS Feed Latest news

Wi-Fi network maintenance 07:00–09:00 Wednesday 18 September

Sep 12, 2019

The University’s wireless service will be unavailable for significant periods between 07:00 and 09:00 on Wednesday 18 September while we carry out essential maintenance work.

Wi-Fi upgrade on Tuesday 10 September between 07:00 and 09:00

Sep 09, 2019

There will be short interruptions to the wireless service on Tuesday 10 September between 07:00 and 09:00 as we implement an upgrade to the operating system. We'll do our best to minimise any disruption.

View all news