Department of Computer Science and Technology

The CL network

a switchThe Computer Lab network is connected via routers to the Cambridge University Data Network (CUDN). This has a connection to the Joint Academic NETwork (JANET), which connects to the Internet as a whole.

All the machines in the Computer Laboratory are subject to the conditions of the University Information Strategy and Services Syndicate (ISSS). In particular use of the CUDN connection implies acceptance of the JANET Acceptable Use Policy. It is important that you do not do any kind of port scanning or security probing, even of your own machines. If your research requires you to do something which might appear suspicious, please contact sys-admin first.

You should also be aware that the department has to pay for traffic to and from sites outside the University. For most normal research requirements this need not concern you, but excessive network use is likely to be noticed and investigated.

Structured wiring

The main router also acts as a central switch – it has fast connections to a filestore and various other machines, and also connects to a set of switches distributed around the building. There are one or more switches in each of the 6 wiring closets on each floor. Each connection on the switches is connected to a patch panel, and the patch panel also has connections into all of the offices.

So, the network appears in offices as a set of 4 RJ45 sockets (i.e. network sockets) in the floor boxes which also house power sockets. A few areas without false floor have the sockets presented on wallplates instead. The RJ45 sockets in the floor boxes are not enabled by default, but need to be set up by a system administrator.

Please do not rearrange connections to sockets yourself — if you need a socket enabled, we have a web form for you to fill in. Go to Request a network connection and fill in the details requested.

If you no longer require a connection, please email sys-admin so that the switch port can be reused.

If there are not enough sockets in a particular place, it may be possible to use a local switch, but please do not connect one without asking first. You can also connect to the network throught the RJ45 socket on the back of your desk phone, which economises on the use of switch ports, but has the disadvantage that most phones restrict the link speed to 100Mbit/s.

Wireless networks

The wireless network is intended to cover the entire William Gates Building and uses equipment rented from and managed by the Computing Service. 802.11b/g/n are supported at 2.4GHz and 802.11n at 5GHz. The physical access points provide more than one logical network, so there are different ESSIDs (i.e. network names) for different purposes.


The ESSID eduroam offers the JANET Roaming Service, and is available to both Cambridge users and visitors who have appropriate credentials from a participating institution. It is the preferred network for people wanting CUDN connectivity from wireless devices. You can connect to eduroam throughout the University, as well as many other institutions worldwide. To find out how to set up eduroam as a local user, please visit the University Information Services pages.

Internal-CL (the local wireless network)

Internal-CL is the local wireless network intended for users who need a Lab IP address. It provides IPv6, and has the minor advantage over Eduroam that packets do not have to travel to the UIS and back again, as they stay on a local VLAN. It also provides access to local printers within the department. The network is setup in a way similar to Eduroam which you should normally configure first. Authentication for Internal-CL uses the same credentials as eduroam, not your Lab account password. Apple iOS users should use the profile provided by the UIS here.


The ESSID UniOfCam is a network offered by the Computing Service using a captive portal access model. It can be used by anybody with a Raven account, and it is also possible for us to issue temporary tickets for visitors, conferences etc. All members of staff may issue short term tickets for their guests; longer-term and bulk tickets are available from the system administrators or Reception.

wgb (visitor access)

The ESSID wgb offers an "open access" network, giving NAT-based internet connectivity via a Demon ADSL line. The intention is primarily to offer a courtesy internet service for visitors to the building without the need to register. Please do not use this network simply because it is the easiest to connect to, as it is not intended for long sessions or bulk transfers — we may be forced to put access restrictions on this network if it turns out to be abused. It may one day be replaced at short notice by a commercial public WiFi service.