A network license (also floating license or concurrent license) relies on a centrally hosted license server to manage the available licenses for a software product. The software on the client sends a request for a license to the license server when it’s launched. If a license is available then the license server will assign one temporarily to the client. The client needs to be online for the software to work and has to be inside the ETH network in order to be able to contact the license server (an active VPN connection is required if the client device is located outside of the ETH network). Some license server products allow licenses to be “borrowed” for a limited amount of time for offline use.
The advantage of a network license is that a limited pool of licenses can be made available to a much larger group of users. This can be very cost effective and forces license compliance since the number of users using the software at the same time is limited by the number of available licenses regardless of the number of software installations.
A node license (also single use license or node-locked license) is locked to your device during the installation and typically requires a license key or license file. It allows offline use and is thus more flexible than a network license but usually more expensive. A node license may require periodical reactivation with a different license key/file or frequent contact with an activation server.
Some software vendors grant the license holder the right to do a second installation of a single license on a private computer at home for situations when a member of the staff has to work from home. Note that private use of a home use installation is generally not permitted. See Home Use of ETH Software for details.
Key Management Server (KMS)
KMS is an activation server for Microsoft’s volume license software (Windows Enterprise, Windows Education and Server OS plus Office for Windows) that is run inside the customer’s network for the purpose of activating Microsoft software installed inside the same network. It was introduced with Windows Vista. Activation usually happens automatically when a KMS is present in the same network but can be triggered manually.
KMS activations are valid for 180 days — the activation validity interval. To remain activated, KMS client computers must renew their activation by connecting to the KMS host at least once every 180 days. By default, KMS client computers attempt to renew their activation every seven days. If KMS activation fails, the client will retry every two hours. After a client computer’s activation is renewed, the activation validity interval is reset.
Multiple Activation Key (MAK)
Microsoft offers Multiple Activation Keys (MAK) for Enterprise software on clients that are not online for 180 days or more at a time (or not at all) and thus not suited to use a KMS server. A MAK has to be issued by Microsoft and allows a limited number of activations specified by the customer. Only available on request and in exceptional cases since there are some technical and compliance issues that come with MAKs.
With a device-based license (per device) the software is licensed for the number of devices it’s installed on. Several users can share a device and use the same license. Depending on the licensing terms moving the license to a different device may not be possible or only under certain conditions. Most software licenses at ETH Zurich are device-based although user-based licenses are becoming more common with an ever increasing number of software vendors offering cloud services.
With a user-based license (also per user or name-based) the software is licensed for a specific user and the right to use a software moves with the person from one device to another. User-based licenses are becoming more common with an ever increasing number of software vendors offering cloud services. Microsoft’s Office 365 is an example for a user-based license using a subscription model.
Software maintenance (Microsoft calls it software assurance) is offered by many software vendors to enterprise customers. It allows to keep purchased licenses up-to-date by paying a yearly percentage (usually around 20%) of the purchase price. As long as the the licenses are kept under maintenance the license holder can download and use the latest version of the software. Once maintenance is cancelled the license holder still owns the licenses originally purchased and can use the software in the last version that was available before maintenance ended.
Some vendors require software maintenance to grant certain use rights (Microsoft is a prominent example) so buying licenses without software maintenance may expose the license holder to compliance risks.
Paying for a software subscription (usually monthly or yearly) means renting the software. You are permitted to install the software a certain number of times and use the latest version as long as you continue to pay for the subscription. If you cancel the subscription you will have to uninstall every single installation and are not permitted to use any version of the software any longer.