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Glossaries

  • Remote Alarm Indication (RAI)
  • Also called a yellow alarm. This happens when the received stream of bits is in a data/framing pattern that indicates the far end is in “red alarm.” Red alarm means a corruption or loss of signal that the equipment is unable to recover from.
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  • Random Access Memory (RAM)
  • Volatile memory in a computer. It has fast access time but it does not preserve its value if the unit is restarted or turned off.
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  • Radio Access Network (RAN)
  • Radio Access Network. This technology has been developed for the transmission to the BTS/Node B/Micro Cell of RF signal. Initially the active equipment BBU was located at the foot of the Antenna. Now the BBU/DU are centralized and 10 to 20km links between BBU/DU and RRU, or RF antenna, are linked with RF signal over fiber. This optical section of the RAN is named Front-haul. One of the WDM1800 missions is to support the Fronthaul and optimized the fiber by CWDM or DWDM multiplexing.
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  • Role-Based Access Control (RBAC)
  • In computer system security, Role-Based Access Control (RBAC) is an approach to restricting system access to authorized users, and to implementing mandatory access control (MAC) or discretionary access control (DAC).
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  • Ringer Equivalence Number (REN)
  • A number that describes the electrical load that a telephone ringer puts on the electrical line. This is important for traditional telephone lines that are powered entirely by the telephone network and not the electrical power grid.
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  • Routing Information Protocol Version 1 (RIP1)
  • A routing protocol using the arrays of distance to other nodes in the network with hop count. To prevent routing loops, RIP has a limit number of hops in a path from the source to a destination, and the maximum number is 15.

    RIPv1 adopts classful routing. The subnet information is not shown in periodic routing updates and lacks Variable Length Subnet Masks (VLSM). In other words, all subnets in a network class must have the same size. In addition, there is no authentication mechanism, causing RIP1 easy to be attacked.
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  • Routing Information Protocol Version 2 (RIP2)
  • The Routing Information Protocol (RIP) is a routing protocol using the arrays of distance to other nodes in the network with hop count. To prevent routing loops, RIP has a limit number of hops in a path from the source to a destination, and the maximum number is 15.

    RIPv2 evolves with the ability to carry subnet information, thus supporting Classless Inter-Domain Routing (CIDR). Unlike RIPv1 using broadcast, RIPv2 uses multicast. This can avoid unnecessary load on hosts that do not participate in routing. Yet unicast is still allowed for special applications. It supports authentication.
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  • Remote Loopback (RLB)
  • Loopback activated at the remote location of a circuit.
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  • Remote Line Loopback (RLLB)
  • Remote loopback of the entire line.
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  • Remote Monitoring (RMON)
  • A type of MIB (management information base) used to monitor and profile LANs. RMON is typically used for flow-based and traffic management while SNMP is used for device-based management.
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  • Radio Network Controller (RNC)
  • Controls Node Bs in a radio network communications system. Typically performs encryption and resource management.
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  • Remote Payload Loopback (RPLB)
  • Remote loopback of the payload portion of the line.
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  • Rapid Spanning Tree Protocol (RSTP)
  • An improvement upon the original STP algorithm. It provides faster convergence after a topology change. Defined by IEEE 802.1w.
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  • Real Time Clock (RTC)
  • A piece of hardware inside a computer or any other electronic device that keeps track of the time.
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  • Request to Send (RTS)
  • A flow control hand-shaking method used in RS-232 or wireless systems. The sending device sends out an RTS frame or signal, and the receiving device send back a CTS or Clear To Send frame.
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