Routing Information Base (RIB): A data table stored in a router or a networked computer that lists the routes to particular network destinations. The RIB contains information about the topology of the network immediately around the router, including the cost (such as path length) associated with reaching each network destination. A router uses this information to determine the best path for forwarding packets. The RIB is built using information from routing protocols (like BGP, OSPF, etc.), and it may contain multiple potential paths to a destination. Routing decisions are made by a router by consulting the RIB and selecting the optimal route from the available entries based on the routing algorithm it uses.

RS-232 interface: A serial communication standard used to connect devices, such as computers and terminals. It is used to transmit data between devices, typically at slow speeds. Examples include a serial cable used to connect a computer to a modem or a serial port used to connect a terminal to a mainframe.

RSA (Rivest-Shamir-Adleman): A widely accepted public key cryptosystem developed by Ron Rivest, Adi Shamir, and Leonard Adleman. It enables secure data transmission and is commonly used for securing sensitive data, particularly when sent over an insecure network. RSA's security comes from the computational difficulty of factoring large composite integers, which is the product of two large prime numbers. RSA is employed in a multitude of security-focused applications, including SSL for web traffic, secure email, and digital signatures.

Rule-based access: An approach to managing access to system resources that revolves around a set of predefined rules. These rules are set up to govern the access capabilities of an entity based on specific conditions, such as IP address, time of access, or the particular service being accessed. This type of control enhances the security of systems by ensuring that access is granted only under defined circumstances, thereby reducing the chances of unauthorized access.

Rule-Based Access Control: An access control method where system access is determined by rules or policies set by an administrator. RuBAC allows for complex operational conditions and is widely used due to its flexibility and ability to enforce granular security policies.

Rule-based management: A management approach that involves establishing and enforcing rules to guide decision-making and behavior within an organization. It is often used in business and government organizations to ensure compliance with regulations and policies. Examples of rule-based management include requiring employees to follow a specific code of conduct or implementing policies to protect customer data.