Calling user, called user, intra-office call, inter-office call, originating end office, receiving end office

Calling and called users: The calling user is the user who initiates the call, which we call the caller, and the called user is the user who receives the call, which we call the receiver.

The end office --- to call the branch office, is the first level of exchange in the local network, which represents

The last level of the telephone network exchange, the following will be connected to the subscriber's phone. Sometimes the end office

is also connected to a subscriber switch. The end office is required to have the standard trunk and subscriber interfaces of the public network, signaling methods, and

electrical parameters, specifications, and performance that conform to the public network specifications in order to interoperate with other exchanges. The

terminal portion of a long-distance network is referred to as the originating and terminating offices.

The long-distance network ---- consists of long-distance switching centers, long-city trunks and long-distance circuits

The network is used to facilitate telephone services between local networks. In China's five-tier hierarchical

structure telephone network, the long-distance network for the four levels, that is, one, two, three, four for long-distance

exchange center. The first level of switching centers are interconnected to form a mesh network, and the following

levels of switching centers are supplemented by a certain number of direct circuits mainly by sinks, thus

constituting a composite network structure.

The sink ---- is a type of switching office within the local network, which sinks the traffic sent by the end

offices through the interrupter and sends it to the corresponding end office.

In principle, a sink only sinks traffic. That is,

it connects only to the trunks and interoperates with the end offices over the trunks. In practice, however,

the sink is often a sink/end office hybrid, where it both sinks end office traffic and receives subscriber traffic, i.e., subscriber handsets.

The sink needs to have the standard trunking interface in the local network, signaling

methods, and electrical specifications and performance to meet the specification requirements, in order to interoperate with other switches in the network

. A switch installed in a sink is called a sink switch.

Access network ---- The International Telecommunication Union Telecommunication Standardization Sector (ITU-T)

recommendations define an access network as a network in which a service node (local exchange for telephony services) is connected to a subscriber's end

site. switch) and the user terminal

implementation system between the service nodes (local switches for telephony services) and the user terminal

devices. It can partially or completely replace the traditional subscriber local line network, and can contain multiplexing, cross-connecting and transmission functions. ITU-T proposed the concept of access network based on the development and evolution of telecommunication networks in recent years, aiming at integrating the local exchange, subscriber loops, and terminal equipment to connect various subscribers to the service network through limited standardized interfaces. interfaces to access various users to the service nodes. The access network can support integrated access for a variety of services including

narrowband and broadband.

Virtual Private Network (VPN) ---- is a functional network built on top of a real network (or physical network), or a way of organizing a private network, called a VPN for short. It provides users with the functionality of a general private network, but is not itself

a separate physical network; it can also be said that a virtual private network is a logical private network. The term "virtual

proposed" suggests that it is different in composition from a real physical network, but functionally identical to a real

private network for the user.

The current virtual private networks can be divided into three categories:

1. Switched-connected circuits implemented on the telephone network to provide users with switched-connected circuit services, which can be used to make calls or to transmit call data;

2. Connected virtual current" msg/new">virtual current"current" msg/new">current.

For the transmission of packet data services;

3. A fixed or semi-fixed

(permanent or semi-permanent) connected circuit service to a subscriber, realized on a digital data network, which can be used for the point-to-point

transmission of services such as data, voice, and images.

ISDN ----- is an evolution of the Integrated Digital Network for Telephony (IDN), which provides end-to-end digital connectivity to support

a wide range of services (both voice and non-voice), providing users with a standardized set of services, including voice and non-voice services. ), providing users with a standard set of multi-purpose user

User ___ network interfaces. In short, it is a network, that is, a set of transmission equipment and a set of switching equipment

to provide a variety of telecommunication services transmission and switching, in order to improve the efficiency of the network and to provide users with more in the convenience.

Fundamental to the realization of this network is the provision of end-to-end digital connectivity.

ADSL-----------ADSL is the most commonly used and mature technology in the DSL (Digital Subscriber Loop) family, which

is an acronym for Asymmetrical Digital Subscriber Loop.

It is a new high-speed, broadband technology running on the original ordinary telephone lines. The so-called asymmetry is mainly reflected

in the asymmetry of the uplink rate (up to 640Kbps) and downlink rate (up to 8Mbps).

Digital Data Network ---------- A data transmission network, or DDN, that utilizes digital channels to transmit data signals.

Digital Data Network is a digital data transmission channel that provides digital data transmission channels to two users in a terminology, and can also provide digital data transmission channels between exchange

switching nodes for public data users. Digital data network can not provide real-time switching functions, but only the use of simple

simple digital cross-connect and multiplexing devices, can be controlled by intelligent control devices to control the appropriate adjustment of the channel routing and signal

channel transmission rate. A digital data network consists of four components: a local transmission system; a multiplexing and cross-connecting

system; an inter-office transmission and clock synchronization system; and a network management system.

Frame Relay ------- transmits and exchanges data in a simplified

on the second layer of the Open Systems Interconnection Reference Model, the digital link layer.

a technique for transmitting and exchanging data units in a simplified manner. One of the important features of Frame Relay is that it is an X.25 packet

network in which the processing of error recovery and congestion prevention through packet retransmission and flow control between nodes is moved to the end part

of the network to be realized, thus simplifying the process at the nodes and reducing the processing time.

The outside line-also known as a trunk-is the connecting line between the programmed switch and the higher-level switch, and is usually the telephone line that the telephone office receives from the subscriber's switch.

Inner line - also known as the extension line, is the user line for each extension of the switch. Analog line - is the line that carries analog signals.

Digital line - is the line that carries digital signals.

Computer operator - refers to the voice prompts issued by the switch when an outside line is called in, such as "Hello XX company, please dial the extension number, please dial 0 to check the number". It can be divided into two types: built-in and external.

Rope path - refers to the analog switch and digital-analog hybrid call channel. The general analog switch's call rope road is designed after strict probability calculations, the switch's call rope road is usually larger than the number of outside line ports and smaller than the number of extension ports.