您在這裡

Glossary
1 8 A B C D E F G H I J L M N O P Q R S T U V W
R
  • RADIUS

Remote Authentication Dial-In User Service
An authentication, authorization and accounting protocol for applications such as network access or IP mobility. Many network services require the presentation of security credentials (such as a username and password or security certificate) in order to connect to the network. Before access to the network is granted, this information is passed to a network access server (NAS) device over the link-layer protocol, then to a RADIUS server over the RADIUS protocol. The RADIUS server checks that the information is correct using authentication schemes like PAP, CHAP or EAP.

  • Redundancy

Backup components used to ensure uninterrupted operation of a system in case of a failure.

  • Repeater

A device which automatically amplifies, restores or reshapes signals to compensate for distortion and/or attenuation prior to retransmission.

  • RIP2

Routing Information Protocol used to discover agents and the routes that IP packets must traverse. This is done automatically using periodic broadcasts. RIP2 also supports IP subnets.

  • RIPII

Routing Information Protocol used to discover agents and the routes that IP packets must traverse. This is done automatically using periodic broadcasts. RIP2 also supports IP subnets.

  • RIPv2

Routing Information Protocol used to discover agents and the routes that IP packets must traverse. This is done automatically using periodic broadcasts. RIP2 also supports IP subnets.

  • RJ-45

A telephone connector that accommodates up to eight wires. RJ-45 plugs and sockets are used in Ethernet and Token Ring devices.

  • Router

An interconnection device that connects individual LANs. Unlike bridges, which logically connect at OSI layer 2, routers provide logical paths at OSI layer 3. Like bridges, remote sites can be connected using routers over dedicated or switched lines to create WANs.

  • Routing

The process of selecting the most efficient circuit path for a message.

  • RSTP

Rapid Spanning Tree Protocol
In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.
While STP can take 30 to 50 seconds to respond to a topology change, RSTP is typically able to respond to changes within 3 × Hello times (default: 3 times 2 seconds) or within a few milliseconds of a physical link failure. The so-called Hello time is an important and configurable time interval that is used by RSTP for several purposes; its default value is 2 seconds.
Standard IEEE 802.1D-2004 incorporates RSTP and obsoletes the original STP standard.

  • RSVP

Resource reSerVation Protocol
A protocol developed for supporting different QoS classes for IP applications.

  • RTS

Request TSend
A modem control signal sent from the DTE to the modem, which tells the modem that the DTE has data to send.

  • RTT

Round Trip Time
The round trip time it takes for a packet to travel between a source and a network device.