Internet1

The Internet A network of computer networks To view the internet or allow user to communicate through it, one must have the necessaryTCP/IPand a web browser.

TCP TCP (Transmission Control Protocol) provides reliable, ordered delivery of a stream of bytes from a program on one computer to another program on another computer.

TCP/IP TCP is the protocol that major Internet applications rely on, applications such as the World Wide Web, e-mail, and file transfer. TCP provides a point-to-point channel for applications that require reliable communications. The Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP) and Telnet are all examples of applications that require a reliable communication channel.

TCP TCP is optimized for accurate delivery rather than timely delivery, and therefore, TCP sometimes incurs relatively long delays (in the order of seconds) while waiting for out-of-order messages or retransmissions of lost messages.

TCP TCP is a reliable stream delivery service that guarantees delivery of a data stream sent from one host to another without duplication or losing data

TCP Other applications, which do not require reliable data stream service, may use the User Datagram Protocol (UDP) which provides a datagram service that emphasizes reduced latency over reliability. Example: Internet Radio Stream, Podcast, Youtube video streaming, CtC

IP The Internet Protocol (IP) is Responsible for routing packets across network boundaries, it is the primary protocol that establishes the Internet. deliver datagrams from the source host to the destination host solely based on their addresses. For this purpose, IP defines addressing methods and structures for datagram encapsulation.

TCP/IP (summary) TCP consists of a set of rules: for the protocol, that are used with the Internet Protocol, and for the IP, to send data "in a form of message units" between computers over the Internet. At the same time that IP takes care of handling the actual delivery of the data, TCP takes care of keeping track of the individual units of data transmission, called segments, that a message is divided into for efficient routing through the network.

TCP provides a communication service at an intermediate level between an application program and the Internet Protocol. That is, when an application program desires to send a large chunk of data across the Internet using IP, instead of breaking the data into IP-sized pieces and issuing a series of IP requests, the software can issue a single request to TCP and let TCP handle the IP details. IP works by exchanging pieces of information called packets. A packet is a sequence of octets and consists of a header followed by a body. The header describes the packet's destination and, optionally, the routers to use for forwarding until it arrives at its destination. The body contains the data IP is transmitting. Due to network congestion, traffic load balancing, or other unpredictable network behavior, IP packets can be lost, duplicated, or delivered out of order. TCP detects these problems, requests retransmission of lost data, rearranges out-of-order data, and even helps minimize network congestion to reduce the occurrence of the other problems. Once the TCP receiver has reassembled the sequence of octets originally transmitted, it passes them to the application program. Thus, TCP abstracts the application's communication from the underlying networking details.

OSI (Open System Interconnection) Model The most popular packet-based structure of layers, or protocol stack It defines 7 layers. The user interface (Application Layer) is the top layer, since users work directly with applications. As you work your way down toward the lower layers, the protocols become more detailed toward the nuts and bolts of the operation. They define the details of actually preparing and moving data.

OSI (Open System Interconnection) Model

OSI (Open System Interconnection) Model (Vertical/Horizontal Communication)

ENCAPSULATION/DECAPSULATION Moving from the top, down - messages get larger and larger ! ! A message is passed down, and the lower layer adds a header to it. This is called encapsulation, because it is like placing an object into a capsule. The header is sometimes called a wrapper. Each successive lower layer encapsulates what it receives from the layer above it.

ENCAPSULATION/DECAPSULATION Moving from the bottom, up - messages get smaller and smaller ! ! A message is first stripped of it's header, and then the inner contents (the "data" portion) is passed up. This is "decapsulation" but no one uses that term. Each successive upper layer receives the data message from the layer below, and then strips off it's own header and passes the data up.

The 7 layers Although there are seven layers in the OSI model, they can be grouped into three areas: High-level Protocols (layers 5, 6 and 7 - Session, Presentation, and Application) - how the data is presented, displayed, and summarized for the user - and in the reverse direction, how the user prepared data is assembled into meaningful data structures (high-level protocols).

The 7 layers Medium-level Protocols (Layers 3 and 4 - Network and Transport) - how the data is assembled into packets and frames and how error checking and flow control is implemented - and in the reverse direction, how the received packets and frames are assembled into structures such as files and databases (medium-level protocols)

The 7 layers Low-level Protocols (Layers 1 and 2 - Physical and DataLink) - how the data is converted into electrical pulses of one's and zero's (bits) and sent across cables or the physical medium, and in the reverse direction, how the electrical pulses are taken off the cable and converted to ones and zero's.

DATA TERMINOLOGY Messages and Packets - catch-all terms used to describe any unit of data being passed between layers

DATA TERMINOLOGY Data - Layer 5, 6, and 7 - not sure why they did not differentiate between these type of data units and call them each by a different name . . . but a good guess is that since data units at these layers are rarely discussed, apparently it was OK to called them all by the same name - simply "Data"

DATA TERMINOLOGY Segment - Layer 4: data units at layer 4 of the OSI model - TCP (Transmission Control Protocol)

DATA TERMINOLOGY Packet - Layer 3: This term is considered by many to most correctly refer to a message sent by protocols operating at the network layer of the OSI Reference Model. So, you will commonly see people refer to “IP packets”.

DATA TERMINOLOGY Datagram - Layer 3: This term is basically synonymous with “packet” and is also used to refer to network layer technologies. It is also often used to refer to a message that is sent at a higher level of the OSI Reference Model (more often than “packet” is).

DATA TERMINOLOGY Frame - Layer 2: most commonly used to refer to Ethernet, Token Ring, or Frame Relay units of data. A frame gets its name from the fact that it is created by taking higher-level packets or datagrams and “framing” them with additional header information needed at the lower level. Cell - Layer 2: most commonly used to refer to 53-byte units of data. A cell is a unit of data that is fixed in size.

DATA TERMINOLOGY Frame - Layer 1: refers to T-Carrier Layer 1 units of data (193-bit frames) BITS – Layer 1; AKA “one’s and zero’s”

BITS and BYTES A byte is composed of combinations of 8 bits. Example: 00000001 = 1 00000011= 2 00000101=3 ………… = 256 (maximum) bits combination Note: 255 is just 1 byte.

BITS and BYTES The recent IP address version 4 or IPv4 is using 32 bits addressing like this: 192.2.34.155 255.255.255.255 (maximum)

Domain Name Server An open source software that converts IP address in number form into labels (letters). Example : your IP address is 192.1.0.222 is equivalent to www. Dipolog.com/

Uniform Resource Locator (URL) Identifies the web address of a document in the internet. An example is HTTP://WWW.INTERNET.COM/list/students.html www.pinoybsn.blogspot.com/crazyme/games.html

DAWN of the NET CLIP 1 CLIP 2 CLIP 3

WIRELESS NETWORK Wireless network refer to any type of computer network that is not connected by cables of any kind.

WIRELESS NETWORK Wireless telecommunications networks are generally implemented and administered using a transmission system called radio waves. This implementation takes place at the physical level, (layer), of the network structure.

TYPES Wireless WAN Wireless PAN Wireless LAN Wireless MAN

WI-FI is 802.11 Wi-Fi: "Wi-Fi" is a term used to describe 802.11 WLANs, although it is technically a declared standard of interoperability between 802.11 devices.

WiMax is 802.16 is a series of Wireless Broadband standards authored by the IEEE. “WiMax” - Worldwide Interoperability for Microwave Access IEEE (Institute of Electrical and Electronic Engineers)

Wireless Broadband (802.16) broadband means "having instantaneous bandwidths greater than 1 MHz and supporting data rates greater than about 1.5 Mbit/s.“ Wireless Broadband networks feature speeds roughly equivalent to wired broadband networks, such as that of DSL or a cable modem.

Wireless Broadband Wireless Broadband networks can also be Symmetrical, meaning bandwidth traveling in both directions (download/upload), which is most commonly associated with 'Fixed Wireless' networks.

House with a wireless broadband

Mobile wireless broadband allow a more mobile version of this broadband access. Consumers can purchase a PC card, laptop card, or USB equipment to connect their PC or laptop to the Internet via cell phone towers. stable in almost any area that could also receive a strong cell phone connection. These connections can cost more for portable convenience as well as having speed limitations in all but urban environments.

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