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R1.5

System R1.5; an international protocol family that includes channel associated signaling protocols used for E1 lines in Russia.

R2 signaling

One of several standards for channel associated signaling. See also CAS.

RAS

Under the H.323 standard, the Registration, Admissions, and Status signaling function. See also H.323.

reason code

Further classification for a DONE event, typically indicating an application problem. See also DONE event.

receive queue

A NaturalFax document queue for receiving documents transmitted from one fax terminal to another. A receive queue must have an allocated entry for each document to be received. Only names of files that do not exist can be enqueued in a receive queue; the file name may not be NULL. See also document queue, send queue.

red alarm

One of the three alarms that indicate problems with T1 transmissions. A red alarm is generated for a locally detected failure, such as loss of synchronization for 2.5 seconds. See also AIS, blue alarm, yellow alarm.

release guard time

An interval in which an inbound protocol remains in blocking state after both parties have hung up.

remote procedure call

Way of implementing communication between a client and a server in the client/server model.

resources

In the TX hardware environment, logical entities that define paths or protocol instances between TX Series software entities (such as TX virtual ports) and peers at other endpoints.

reverse connection

A type of full-duplex switch connection. In MVIP-90, this describes the mapping of full-duplex connections such that the 8 input streams are tied to the upper 8 inputs of the switch block and the upper 8 outputs of the switch block are tied to the 8 output streams. See also forward connection, full-duplex.

reverse-make-busy

A change in out-of-band line signaling that blocks the remote end from offering any calls.

right clocks

MC1 clock signals driven by the primary or secondary clock master. See also left clocks, primary [clock] master, secondary [clock] master.

ring

The alerting signal to the subscriber or terminal equipment; also the name for one conductor of a wire pair, designated by R. The other is called tip, or T. See also tip.

robbed-bit signaling

A signaling method that uses the least significant bit of each timeslot in every sixth frame to carry signaling information (on-hook, off-hook, etc.) for that voice channel. See also D4 framing.

router

A device used to extend the size of a network. Routers operate at the network layer of the OSI model.

routing

The process of finding an available path or sequence of paths that create a desired connection.

RS-232C

A technical specification published by the U.S. Electronic Industries Association that specifies the mechanical and electrical characteristics of the interface for connecting Data Terminal Equipment (DTE) to Data Communications Equipment (DCE). It defines interface circuit functions and their corresponding connector pin assignments. Most computer serial ports are based on RS-232C.

RTCP

Real Time transport Control Protocol; a protocol designed to control the latency of audio or videographic data sent over LAN networks.

RTCP packet

A control packet consisting of a fixed header part similar to that of RTP data packets, followed by structured elements that vary depending upon the RTCP packet type.

RTP

Real Time transport Protocol; a layer added to the Internet protocol (IP) that addresses latency problems caused when real-time interactive exchanges (such as video) are conducted over lines designed to carry packet-switched (connectionless) data.

RTP/RTCP

The real-time transport (and control) protocol. Provides end-to-end delivery services for data with real-time characteristics, such as interactive audio and video. Services include payload type identification, sequence numbering, timestamping and delivery monitoring. Implemented in both the TX-based and host-based Fusion 2.x product.

RTP media type

The collection of payload types which can be carried within a single RTP session. The RTP Profile assigns RTP media types to RTP payload types.

RTP packet

A data packet consisting of a fixed RTP header, a list of contributing sources (which can be empty), and the payload data. Some underlying protocols may require an encapsulation of the RTP packet to be defined.

RTP payload

The data transported by RTP in a packet, for example, audio samples, or compressed video data.

RTP session

The association among a set of participants communicating with RTP. For each participant, the session is defined by a particular pair of destination transport addresses (one network address plus a port pair for RTP and RTCP). The destination transport address pair can be common for all participants, as in the case of IP multicast, or can be different for each, as in the case of individual unicast network addresses and port pairs. In a multimedia session, each medium is carried in a separate RTP session with its own RTCP packets. The multiple RTP sessions are distinguished by different port number pairs and/or different multicast addresses.

runfile

Mandatory low-level runtime software which is downloaded to an AG board as part of its initialization. The runfile for a board is specified in the AG configuration file. When agmon runs, it transfers the runfile from the host into on-board memory. See also agmon.

runtime functions

Service manager binding functions for command processing, error handling, trace handling, and event processing.