CushionTheBlow (구 BluemoonSoft)

An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices together directly where they would normally be connected via a network switch, hub or router. For example, one would use a crossover cable to directly connect two personal computers via their network adapters.

Overview
The 10BASE-T and 100BASE-TX Ethernet standards use one wire pair for transmission in each direction. The Tx+ line from each device connects to the tip conductor and the Tx- line is connected to the ring. This requires that the transmit pair of each device be connected to the receive pair of the device on the other end. When a terminal device is connected to a switch or hub, this crossover is done internally in the switch or hub. A standard straight through cable is used for this purpose where each pin of the connector on one end is connected to the corresponding pin on the other connector.

One terminal device may be connected directly to another without the use of a switch or hub, but in that case the crossover must be done externally in the cable. Since 10BASE-T and 100BASE-TX use pairs 2 and 3, these two pairs must be swapped in the cable. This is a crossover cable. A crossover cable must also be used to connect two internally crossed devices (e.g., two hubs) as the internal crossovers cancel each other out. This can also be accomplished by using a straight through cable in series with a modular crossover adapter.

Because the only difference between the TIA/EIA-568-A and T568B pin/pair assignments are that pairs 2 and 3 are swapped, a crossover cable may be envisioned as a cable with one connector following T568A and the other T568B. Such a cable will work for 10BASE-T or 100BASE-TX. 1000BASE-T4 (Gigabit crossover) which uses all four pairs requires the other two pairs (1 and 4) to be swapped and also requires the solid/striped within each of those two pairs to be swapped.

Reference:
http://en.wikipedia.org/wiki/Ethernet_crossover_cable

In computer networking, flow control is the process of managing the rate of data transmission between two nodes. This should be distinguished from congestion control, which is used for controlling the flow of data when congestion has actually occurred. Flow control mechanisms can be classified by whether or not the receiving node sends feedback to the sending node.

Flow control is important because it is possible for a sending computer to transmit information at a faster rate than the destination computer can receive and process them. This can happen if the receiving computers have a heavy traffic load in comparison to the sending computer, or if the receiving computer has less processing power than the sending computer.

Reference:
http://en.wikipedia.org/wiki/Flow_control

A Data circuit-terminating equipment (DCE) is a device that sits between the data terminal equipment (DTE) and a transmission circuit. It is also called data communications equipment and data carrier equipment.

In a data station, the DCE performs functions such as signal conversion, coding, and line clocking and may be a part of the DTE or intermediate equipment. Interfacing equipment may be required to couple the data terminal equipment (DTE) into a transmission circuit or channel and from a transmission circuit or channel into the DTE.

Although the terms are most commonly used with RS-232, several data communications standards define different types of interfaces between a DCE and a DTE. The DCE is a device that communicates with a DTE device in these standards. Standards that use this nomenclature include:

Federal Standard 1037C, MIL-STD-188
RS-232
Certain ITU-T standards in the V series (notably V.24 and V.35)
Certain ITU-T standards in the X series (notably X.21 and X.25)
A general rule is that DCE devices provide the clock signal (internal clocking) and the DTE device synchronizes on the provided clock (external clocking). D-sub connectors follow another rule for pin assignment. DTE devices usually transmit on pin connector number 2 and receive on pin connector number 3. DCE devices are just the opposite: pin connector number 2 receives and pin connector number 3 transmits the signals.

Usually, the DTE device is the terminal (or computer), and the DCE is a modem.

When two devices that are both DTE or both DCE that must be connected together without a modem or a similar media translator between them, a null modem must be used.

Reference:
http://en.wikipedia.org/wiki/Data_circuit-terminating_equipment

Ethernet flow control is a mechanism for temporarily stopping the transmission of data on an Ethernet computer network.

Ethernet is a specific computer network protocol. Flow control in Ethernet resides on the data link layer. A situation may arise where a sending station (computer) may be transmitting data faster than some other part of the network (including the receiving station) can accept it. The overwhelmed network element will send a PAUSE frame, which halts the transmission of the sender for a specified period of time.

PAUSE is a flow control mechanism on full duplex Ethernet link segments defined by IEEE 802.3x and uses MAC Control frames to carry the PAUSE commands. The MAC Control opcode for PAUSE is 0X0001 (hexadecimal). Only stations configured for full-duplex operation may send PAUSE frames.

When a station wishes to send a PAUSE command, it sends the MAC Control frame to the 48-bit destination multicast MAC address of 01-80-C2-00-00-01. This particular address has been reserved for use in PAUSE frames. The use of a well-known address simplifies the flow control process by making it unnecessary for a station at one end of the link to discover and store the address of the station at the other end of the link.

Another advantage of using this multicast address arises from the use of flow control between network switches. The particular multicast address used is selected from a range of address which have been reserved by the IEEE 802.1D standard (which specifies the operation of switches). Normally, a frame with a multicast destination that is sent to a switch will be forwarded out all other ports of the switch. However, this range of multicast address is special and will not be forwarded by an 802.1D-compliant switch. Instead, frames sent to this address are understood by the switch to be frames meant to be acted upon within the switch.

A PAUSE frame includes the period of pause time being requested, in the form of two byte unsigned integer (0 through 65535). This number is the requested duration of the pause. The pause time is measured in units of pause "quanta", where each unit is equal to 512 bit times.

Reference:
http://en.wikipedia.org/wiki/Ethernet_flow_control

A switching center is a node in a telecommunications Circuit switching network which is connected to either another switching center and/or to end user devices. Switching centers are aware of other centers and possible routes between them such that on demand a center can establish an optimal route for a demanded circuit. An optimal route may involve selection of circuit size, latency, bit error rate BER or other Quality of service parameters. The decision is based on the condition prevailing at the time in the network.

Compare packet switching networks which make some of these decisions for each packet of a data exchange.

Reference:
http://en.wikipedia.org/wiki/Switching_center

Data terminal equipment (DTE) is an end instrument that converts user information into signals for transmission or reconverts received signals into user information. A DTE device communicates with the data circuit-terminating equipment (DCE). The DTE/DCE classification was introduced by IBM.

A DTE is the functional unit of a data station that serves as a data source or a data sink and provides for the data communication control function to be performed in accordance with link protocol.

The data terminal equipment may be a single piece of equipment or an interconnected subsystem of multiple pieces of equipment that perform all the required functions necessary to permit users to communicate. A user interacts with the DTE (e.g. through a human-machine interface), or the DTE may be the user.

Usually, the DTE device is the terminal (or a computer emulating a terminal), and the DCE is a modem.

DTE is usually a male connector and DCE is a female connector.

A general rule is that DCE devices provide the clock signal (internal clocking) and the DTE device synchronizes on the provided clock (external clocking). D-sub connectors follow another rule for pin assignment. DTE devices usually transmit on pin connector number 2 and receive on pin connector number 3. DCE devices are just the opposite: pin connector number 2 receives and pin connector number 3 transmits the signals.

This term is also generally used in the Telco context to designate any device unable to generate clock signs, hence a PC to PC ethernet connection can also be called a DTE to DTE communication. This communication is done via an Ethernet crossover cable as opposed to a PC to DCE (hub, switch, or bridge) communication which is done via an Ethernet straight cable.

Reference:
http://en.wikipedia.org/wiki/Data_terminal_equipment

해당 프로세스를 종료시키기 위해서는

'Windows 작업 관리자'를 실행시켜서 프로세스 정보가 일치하는 프로세스를 찾아 종료합니다.

동일한 이미지 이름이 여러 개라면 다음과 같이 PID로 식별해야 합니다.

보기 -> 열 선택

PID(프로세스 식별자)를 체크합니다.

PID가 일치하는 프로세스를 선택하고 '프로세스 끝내기' 버튼을 클릭합니다.

PID를 모른다면, let me know how to handle this :-p

현재 열린 포트를 확인하기 위해서는 netstat 명령어를 사용합니다. '/?' 옵션을 주면 다음과 같은 도움말을 얻을 수 있습니다.

특정 프로토콜의 특정 포트가 열렸는지 알고 싶다면 다음과 같이 할 수 있습니다.

위 명령어는 MySQL 서버 포트인 3306/TCP에 대해 확인을 하고 있습니다.

해당 포트를 점유하고 있는 프로세스를 알고 싶다면 다음과 같이 할 수 있습니다.

첫번째 명령으로 해당 포트를 점유하고 있는 PID를 얻고,

두번째 명령으로 해당 PID에 대한 프로세스 정보를 얻을 수 있습니다.

In telecommunication, the term terminal equipment has the following meanings:

- Communications equipment at either end of a communications link, used to permit the stations involved to accomplish the mission for which the link was established.
- In radio-relay systems, equipment used at points where data are inserted or derived, as distinct from equipment used only to relay a reconstituted signal.
- Telephone and telegraph switchboards and other centrally located equipment at which communications circuits are terminated.

Reference:
http://en.wikipedia.org/wiki/Terminal_equipment