Glossary

Here you will find a brief compilation of definitions and explanations of terms and abbreviations used on the RRZ website.

• Access point (AP) 
  An access point is a device that can be used to establish a wireless connection to a data network. The AP itself is usually connected to the data network via a cable.
• AES
  The Advanced Encryption Standard (AES) is an encryption method that uses the Rijndael algorithm. The AES method was developed as part of a competition organized by the US National Institute of Standards and Technology (NIST) and subsequently standardized. The method may be used freely without the payment of license fees.
• DHCP
  The Dynamic Host Configuration Protocol enables the automatic assignment of IP addresses and other configuration parameters to a computer.
• eduroam
  eduroam (education roaming) is a global roaming service specifically for institutions in the fields of education and science. Institutions from Europe, North America (Canada), and the Asia-Pacific region (e.g., Australia, Japan, and China) currently participate in the network. Further information can be found on the eduroam homepage (https://www.eduroam.org).
• HTML (Hypertext Markup Language)
  Markup language for structuring hypertext documents. HTML documents are the basis of the WWW.
• HTTP (Hypertext Transfer Protocol)
  Stateless protocol used for the transmission of HTML documents.
• IP address
  The Internet Protocol address is a globally unique number that a computer on the Internet needs in order to use the services offered, e.g., WWW services. This is either configured manually or assigned automatically via DHCP.
• Protocol
  In the context of data technology, a protocol is a collection of rules and agreements for the exchange of information. Since data transmission never involves just the information itself, e.g., the text of an email, but also information about where the data is going, where it comes from, and whether the data is encrypted and, if so, using which method, it is necessary to define a set of rules that precisely specifies the structure of the transmitted data. Otherwise, it would not be possible to interpret the received data correctly and make it accessible to the recipient in a meaningful way.
• There are a large number of different protocols for data exchange via IT networks, each of which has been optimized for a specific purpose. Some examples include the Hypertext Transfer Protocol (http), the File Transfer Protocol (ftp), and the Transmission Control Protocol / Internet Protocol (TCP/IP) protocols.
• Proxy server
  If a proxy server is used, all data traffic is handled via this server. This enables both caching and thus accelerated access to the retrieved content, as well as the definition of rules for access.
• Radius
  The Radius service (Remote Authentication Dial In User Service) is used to verify user access authorizations. A client (e.g., a VPN client program) transmits the access data (user name and password) provided by the user to a Radius server, which then decides whether to grant or deny access to the user based on stored information. If configured accordingly, the Radius server can forward the transmitted access information to another Radius server. This makes it possible, for example, for users from other institutions to connect to the public network access points at the University of Hamburg using the access information from their home institution and use them to access the internet. The prerequisite for this is that the home institution participates in one of the roaming associations in which the University of Hamburg also participates (see eduroam and CASG).
• Roaming
  Roaming refers to the use of a third-party provider's access infrastructure. The term originally comes from the field of mobile telephony, where it refers to the ability to receive and make calls abroad using one's own mobile phone via the mobile network of a local operator. For roaming, i.e., the use of the network access infrastructure by guests, it is necessary to have the login information confirmed by the respective home institution. Various associations have come together to coordinate access procedures and ensure the widest possible distribution. The University of Hamburg is a member of the eduroam and DFN-CASG roaming associations. In addition, there are smaller associations with neighboring institutions, such as the Technical University of Hamburg.
• SSID
  The Service Set Identifier is the identifier or name of a wireless network.
• VPN
  A virtual private network is a connection that establishes a secure (encrypted) connection over an unsecured network. To access a VPN, a corresponding program (VPN client) is required on the local computer. The data is transmitted in encrypted form between the VPN client and the VPN gateway. Along the way, the data can only be intercepted in encrypted and therefore incomprehensible form. With the help of the UHH VPN, it is therefore possible, for example, to use untrusted Wi-Fi access points in a secure manner. An example of this is unsecured Wi-Fi access in an internet café, where, without the use of VPN access, there is always the possibility that the Wi-Fi operator can read all data traffic.
• VPN client
  See VPN.
• WCMS
  Abbreviation for web content management system. This is server-based software for editing and managing websites, web pages, and documents and media provided on websites. It is usually used via a web browser.
• WPA/WPA2
  Wi-Fi Protected Access (WPA) and its further development WPA2 are methods for securing the connection between a mobile device and an access point. Both methods allow users to log in either with a pre-shared key, which must be known to all users, or by verifying user data with the help of a Radius server. In private settings, a pre-shared key is often used, while for WLAN access at the University of Hamburg via the SSID UHH-WPA, Radius server login is used, whereby each user is assigned an individual key for each session. This prevents other participants from intercepting the data transmitted between the notebook and the access point.