Now is the time . . .

glibc : GNU C 라이브러리(줄여서 glibc)는 GNU 프로젝트의 일환으로 만든 C 표준 라이브러리의 한
             종류이다.

EABI : EABI(임베디드 응용 프로그램 이진 인터페이스, embedded-application binary
            interface)는 임베디드 소프트웨어 프로그램을 수행하는 파일 형식, 자료형, 레지스터 사
            용, 스택 프레임 조직, 명령 변수를 위한 표준 변환을 정의하고 있다.

• In a communications network, a network node equipped for interfacing with another network that uses different protocols.
  • A gateway may contain devices such as protocol translators, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide system interoperability. It also requires the establishment of mutually acceptable administrative procedures between both networks.
  • A protocol translation/mapping gateway interconnects networks with different network protocol technologies by performing the required protocol conversions.
• Loosely, a computer configured to perform the tasks of a gateway. For a specific case, see default gateway.

Routers exemplify special cases of gateways.

Gateways, also called protocol converters, can operate at any layer of the OSI model. The job of a gateway is much more complex than that of a router or switch. Typically, a gateway must convert one protocol stack into another.


Router :

A router, pronounced /ˈraʊtər/ in the United States and Canada, and /ˈruːtər/ in the UK and Ireland (to differentiate it from the tool used to rout wood), is a purposely customized computer used to forward data among computer networks beyond directly connected devices. (The directly connected devices are said to be in LAN, where data are forwarded using Network switches.)

More technically, a router is a networking device whose software and hardware [in combination] are customized to the tasks of routing and forwarding information. A router differs from an ordinary computer in that it needs special hardware, called interface cards, to connect to remote devices through either copper cables or Optical fiber cable. These interface cards are in fact small computers that are specialized to convert electric signals from one form to another, with embedded CPU or ASIC, or both. In the case of optical fiber, the interface cards (also called ports) convert between optical signals and electrical signals.

Routers connect two or more logical subnets, which do not share a common network address. The subnets in the router do not necessarily map one-to-one to the physical interfaces of the router.^[1] The term "layer 3 switching" is used often interchangeably with the term "routing". The term switching is generally used to refer to data forwarding between two network devices that share a common network address. This is also called layer 2 switching or LAN switching.

Conceptually, a router operates in two operational planes (or sub-systems):^[2]

• Control plane: where a router builds a table (called routing table) as how a packet should be forwarded through which interface, by using either statically configured statements (called statical routes) or by exchanging information with other routers in the network through a dynamical routing protocol;
• Forwarding plane: where the router actually forwards the traffic (or called packets in IP protocol) from ingress (incoming) interfaces to an egress (outgoing) interface that is appropriate for the the destination address that the packet carries with it, by following rules derived from the routing table that has been built in the control plane.

An intent is an abstract description of an operation to be performed. It can be used with startActivity to launch an Activity, broadcastIntent to send it to any interested BroadcastReceiver components, and startService(Intent) or bindService(Intent, ServiceConnection, int) to communicate with a background Service.

An Intent provides a facility for performing late runtime binding between the code in different applications. Its most significant use is in the launching of activities, where it can be thought of as the glue between activities. It is basically a passive data structure holding an abstract description of an action to be performed. The primary pieces of information in an intent are:

• action -- The general action to be performed, such as ACTION_VIEW, ACTION_EDIT, ACTION_MAIN, etc.

• data -- The data to operate on, such as a person record in the contacts database, expressed as a Uri.

<MCC/MNC>

An International Mobile Subscriber Identity or IMSI (pronounced /ˈɪmzi/) is a unique number associated with all GSM and UMTS network mobile phone users. It is stored in the SIM inside the phone and is sent by the phone to the network. It is also used for acquiring other details of the mobile in the Home Location Register (HLR) or as locally copied in the Visitor Location Register. To prevent eavesdroppers identifying and tracking the subscriber on the radio interface, the IMSI is sent as rarely as possible and a randomly-generated TMSI is sent instead.

The IMSI is used in any mobile network that interconnects with other networks, in particular CDMA and EVDO networks as well as GSM networks. This number is provisioned in the phone directly or in the R-UIM card (a CDMA analogue equivalent to a SIM card in GSM).

An IMSI is usually 15 digits long, but can be shorter (for example MTN South Africa's old IMSIs that are still being used in the market are 14 digits). The first 3 digits are the Mobile Country Code (MCC), and is followed by the Mobile Network Code (MNC), either 2 digits (European standard) or 3 digits (North American standard). The remaining digits are the mobile station identification number (MSIN) within the network's customer base.