Term
|
Definition
| In Fame Relay, the physical serial link that connects a Frame Relay DTE device, usually a router, to a Frame Relay switch. The access link uses the same physical layer standards as do point-to-point leased lines. |
|
|
Term
|
Definition
| A serial link between two routers, created without CSU/DSUs, by connecting a DTW cable to one router and a DCE cable to the other. Typically used in labs to build serial links without the expense of an actual leased line from the telco. |
|
|
Term
|
Definition
| The process of supplying a signal over a cable, either on a separate pin on a serial cable or as part of the signal transitions in the transmitted signal, so that the receiving device can keep synchronization with the sending device. |
|
|
Term
|
Definition
| Data Terminal Equipment. From a Layer 1 perspective, the DTE synchronizes its clock based on the clock sent by the DCE. From a packet switching perspective, the DTE is the device outside the service's providers network, typically a router. |
|
|
Term
|
Definition
| Channel Service Unit/ Data Service Unit. A device that understands the Layer 1 details of serial links installed by a telco and how to use a serial cable to communicate with networking equipment such as routers. |
|
|
Term
|
Definition
| Data Communication Equipment. From a physical perspective, the device providing the clocking on a WAN link, typically a CSU/DSU, is the DCE. From a packet-switching perspective, the service provider's switch, to which a router might connect, is considered the DCE. |
|
|
Term
|
Definition
| Digital Signal level 0. a 64 kbps line or channel of a faster line inside a telco whose origins are to support a single voice call using the original voice (PCM) codecs. |
|
|
Term
|
Definition
| Digital Signal level 1. A 1.544 Mbps line from a telco, with 24 DSO channels of 64 kbps each, plus an 8 kbps management and framing channel. Also called a T1. |
|
|
Term
|
Definition
| An international standard data-link protocol that defines the capabilities to create a frame-switched (packet-switched) service, allowing the DTE devices (typically routers) to send data to many other devices using a single physical connection to the Frame Relay service. |
|
|
Term
|
Definition
| High-Level Data Link Control. A bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). |
|
|
Term
|
Definition
| A serial communication circuit between two points, provided by some service provider, typically a telephone company (telco). Because the telco does not sell a physical cable between two endpoints, instead charging a monthly fee for the ability to send bits between the two sites, the service is considered to be a leased service. |
|
|
Term
|
Definition
| A generic reference to networking services; typically WAN services, in which the service examines the contents of the transmitted data to make some type if forwarding decision. This term is mainly used to contrast with the WAN term circuit switching, in which the provider sets up a (Layer 1) circuit between two devices, and the provider makes no attempt to interpret the meaning of the bits. |
|
|
Term
|
Definition
| Point-to-Point Protocol. A protocol that provides router-to-router and host-to-network connections over synchronous point-to-point and asynchronous point-to-point circuits. |
|
|
Term
|
Definition
| A type of cable with many different styles of connectors used to connect a router to an external CSU/DSU on a leased line installation. |
|
|
Term
|
Definition
| The imposition of time ordering on a bit stream. Practically, a device will try to use the same speed as another device on the other end of a serial link. However, by examining transitions between voltage states on the link, the device can notice slight variations in the speed on each end and can adjust its speed accordingly. |
|
|
Term
|
Definition
| A line from a telco that allows transmission of data at 1.544 Mbps, with the ability to treat the line as 24 different 64 kbps DS0 channels (plus 8 kbps of overhead) |
|
|
Term
|
Definition
| In packet-switched services like Frame Relay, VC refers fo the ability of two DTE devices (typically routers) to send and receive data directly to each other, which supplies the same function as a physical leased line (leased circuit), but doing so without a physical circuit. This term is meant as a contrast with a leased line or leased circuit. |
|
|
Term
|
Definition
|
|
Term
|
Definition
1.544 Mbps
(24 DS0s, plus 8 kbps overhead) |
|
|
Term
|
Definition
44.736 Mbps
(28 DS1s, plus management overhead) |
|
|
Term
|
Definition
|
|
Term
|
Definition
34.368 Mbps
(16 E1s, plus management overhead) |
|
|
Term
|
Definition
2.048 Mbps
(32 DS0s; Japanese standard) |
|
|
Term
| Format of Standard HDLC Frame |
|
Definition
| Flag (1), Address (1), Control (1), Data (*), FCS (4) |
|
|
Term
| Format of Cisco HDLC frame |
|
Definition
| Flag (1), Address (1), Control (1), Type (2) Data (*), FCS (4) |
|
|
Term
|
Definition
| The device to which the other devices on the link adjust their speed when using synchronous links. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| A line from the Telco with four wires, comprised of two twisted-pair wires. Each pair is used to send in one direction, so a four-wire circuit allows full-duplex communication. |
|
|
Term
|
Definition
| Similar to a T1, but used in Europe. It uses a rate of 2.048 Mbps and 32 64-kbps channels. |
|
|
Term
List:
Synonyms for "point-to-point leased line" |
|
Definition
| Leased line, leased circuit, link, serial link, serial line, point-to-point link, circuit |
|
|
