Network time

Maintain a consistent time reference across your infrastructure to manage, debug and protect your network.

Network time synchronises the computer clock times in your network to within a few milliseconds, ensuring that the devices connected to your IP network are adjusted to the same time. Time synchronisation is critical on a modern infrastructure network. It’s essential for ensuring staff and students don't miss meetings or lectures and for enabling your security teams to operate efficiently.

Available as part of your Janet connection, we deliver a stable time reference using the network time specified in RFC 5905. Our system provides stratum-1 time servers that are geographically distributed across the network and use various technologies to ensure accurate and consistent time references such as atomic clocks, GPS and the radio time signals MSF (UK) and DCF-77 (Europe).


The network time protocol ensures a consistent time across your infrastructure, bringing these benefits:

  • Accurate logging and auditing on devices help to reduce the time required to correlate events from multiple sources, such as firewalls, intrusion systems (IDS/IPS) and servers, which enables network security teams to respond to security events quickly and with better intelligence
  • Time-based technologies such as certificates, DNSSEC and one time passcodes (OTP) become easier to maintain, even when spread over diverse logical and physical locations
  • Network critical services such as clustering and systems automation require time-sensitive actions
  • Network latency metrics and benchmarking are enabled
  • Accurate time synchronisation is a requirement for PCI DSS compliance
  • Provides digital CCTV timestamping
  • Logs accurate time-based events from devices such as environmental monitors
  • Our systems support both IPv4 and IPv6.

Register for the service

To register your Janet-connected organisation please complete the online application form.

Register for network time

Service updates

Infrastructure refresh 2021-2023

Jisc’s critical services team is undertaking a programme of infrastructure renewal:

  • The introduction of GNSS (Global Navigation Satellite System) allowing us to access not just GPS, but also Galileo systems alongside DCF-77, MSF and Rubidium
  • A refresh of the underlying network time infrastructure to meet the challenges of a modern network

In order to complete this programme of work, we are migrating our current infrastructure onto the new platforms with a small planned outage to each of the five server network time appliances.

Dates for the remaining upgrades will be regularly updated via our community page. Please note that the service will remain up at all times.

Whilst this infrastructure work is taking place, we strongly recommend that you configure more than one network time server as a failover to ensure continuity of service (see support and advice below).

If you have any questions regarding this service refresh or require any technical assistance, please email

Support and advice

It is recommended that an organisation should choose between two to four local systems to be stratum-2 servers. The local server systems do not have to be reserved systems - they can do other work. However, they should be physically distributed around the organisation, so that they are not all on the same power supply or the same segment of a LAN.

Each local server should be configured as a client of a Janet stratum-1 server, and as a peer to the other stratum-2s at the organisation.

Service level description

Service description

A service to provide a high quality time reference service for use by organisations in accordance with RFC 5905.

Hours of service

The service is available 24 hours a day, seven days a week all year.

Target availability

The target availability is 100%. 

Fault management

Faults with the service may be reported via the service desk on tel: 0300 300 2212 or via email:


The service comprises multiple servers which replicate the service.


Organisations must ensure they understand and adhere to the security policy.

Your responsibilities

You are responsible for providing all relevant information requested by Jisc to enable the processing of the application.

You are also responsible on an ongoing basis for maintaining contact details.


This service is centrally-funded.

Request for service

Request this service via the service desk on tel: 0300 300 2212 or via email:

Service delivery time

Within five business days, as defined in SLD definitions, of receipt of all necessary information.

Terms and conditions

Organisations must ensure they understand and adhere to the Janet Network terms and conditions.


If you are experiencing an issue with the service, and wish to escalate the issue within Jisc please contact us via the service desk on tel: 0300 300 2212 or via email:

Technical section

This service supports IPv4 and IPv6. See further service technical details.

ISO certification

This service is included within the scope of our ISO9001 and ISO27001 certificates.

Read more about International Organisation for Standardisation (ISO) standards and view Jisc certificates.

ISO 9001-2015 UKAS logo

ISO/IEC 27001 UKAS logo