NETWORKING REVIEWER.docx

**NETWORKING REVIEWER** **\*LOCAL NETWORKS\*** **Small Home Networks** - connect a few computers to each other and to the internet. **Small Office and Home Office Networks (SOHO networks)** - allows computers in a home office or a remote office to connect to a corporate network or access centrali...

**NETWORKING REVIEWER** **\*LOCAL NETWORKS\*** **Small Home Networks** - connect a few computers to each other and to the internet. **Small Office and Home Office Networks (SOHO networks)** - allows computers in a home office or a remote office to connect to a corporate network or access centralized shared resources. **Medium to Large Networks** - such as those used by corporations and schools, can have many locations with hundreds or thousands of interconnected hosts. **World Wide Network (WWN)** - is a network of networks that connects hundreds of millions of computers world-wide. **\*MOBILE DEVICES\*** **Smartphone** - are able to connect to the internet from almost anywhere. **Tablet** - also have the functionality of multiple devices. **Smartwatch** - can connect to a smartphone to provide the user with alerts and messages. **\*CONNECTED HOME DEVICES\*** **Security System** - many of the items in a home, such as security systems, lighting, and climate controls can be monitored and configure remotely using a mobile device. **Appliances** - household appliances such as refrigerators, ovens, and dishwashers can be connected to the internet. **Smart TV** - can be connected to the internet to access without the need for TV service provider internet. **Gaming console** - can be connected to the internet to download games and play with friends online. **\*OTHER DEVICES\*** **Smart Cars** - many modern cars can connect to the internet to access maps, audio and video content, or information about the destination. **RFID Tags** - radio frequency identification (RFIDs) tags can be placed in or on objects to track them. **Sensors and Actuators** - can provide temperature, humidity, wind speed, barometric pressure, and soil moisture data. **Medical Devices** - such as pacemakers, insulin pumps, and hospital monitors users. **\*DATA TRANSMISSION\*** **Data** - raw facts or unprocessed clues to an information. **BIT or Binary Digit** - is stored and transmitted as one of two possible discrete states. **= HOW DATA COULD BE TRANSMITED =** **Electrical signals** - transmission is achieved by representing data as electrical pulses on copper wire. **Optical signals** - transmission is achieved by converting electrical signals into light pulses. **Wireless signals** - transmission is achieved by using infrared, microwave, or radio waves through the air. **\*BIT NAME, VALUES, AND SIZES(in bytes)\*** Bit - 1 Bit - 1/9 Nibble - 4 Bits - 1/2(rare) Byte - 8 Bits - 1 Kilobyte - 1024 Bytes - 1024 Megabyte - 1,024 Kilobytes - 1024² Gigabyte - 1, 024 Megabytes - 1024³ Terabyte - 1, 024 Gigabytes - 1024⁴ Petabyte - 1, 024 Terabytes - 1024⁵ Exabyte - 1, 024 Petabytes - 1024⁶ Zettabyte - 1, 024 Exabytes - 1024⁷ Yottabyte - 1, 024 Zettabytes - 1024⁸ **Bandwidth** - is a measurement indicating the maximum capacity of a wired or wireless communications link to transmit data over a network. **Data Latency** - refers to the amount of time, including delays, for data to travel from one given point to another. **Throughpu**t - is a measurement of the transfer of bits across the media. \- the amount of data being send and receive over the connection. **Ping (packet internet groper)** - is a method for determining communication latency between two networks or ping. **\*NETWORK COMPONENTS AND TYPES AND CONNECTIONS\*** **Hosts** - all computers connected to a network that participate directly in network communication are classified as hosts. **Client** - are that enable the acquisition of information and provides data. **Server** - are the one who provide information according to the request. **= TYPES OF SERVERS =** **Application Server** -- a program in computer that provides the business logic for an application program. **Web Server** -- a computer program that serves requested HTML pages or files. **Proxy Server** -- is a software that acts as an from which a user is requesting. **Mail Server** -- is an application that receives incoming e-mail from local users and remote senders and forward outgoing e-mail for delivery. **File Server** -- is a computer responsible for central storage and management of data files so that other computer on the same network can access them. **Policy Server** -- is a security component of a policy -- based network that provides authorization services and facilities tracking and control of files. **Peer to peer network** - client and server software usually run on separate computers, but it is also possible for one computer to run both client and server software at the same time. **\*ADVANTAGE OF PEER TO PEER NETWORK\*** \- easy to set up \- less complex \- lower cost \- can be used for simple tasks **\*DISADVANTAGE OF PEER TO PEER NETWORK\*** \- no centralized administration \- not as secure \- not scalable \- all devices may act as both clients and servers **\*END DEVICES\*** **PC (personal computer)** - Represent desktop or laptop computers that users interact with. They are typically used to simulate client devices in a network. **Laptops** -- Similar to PCs but portable, often connected to the network via wireless access points. **Servers** -- Devices that provide services like web hosting, email, DHCP, DNS, etc., to other devices on the network. **Printers** -- Network printers that can be accessed and managed over the network. **Tablets/Smartphones** -- Mobile devices that simulate wireless communication, often connecting through Wi-Fi access points. **VoIP Phones** -- Used for simulating Voice over IP (VoIP) communications within the network. **Smart Devices (IoT)** -- Includes smart appliances, security cameras, and other Internet of Things (IoT) devices that are increasingly part of modern networks. **switch** - send a file or message only to a specific destination. **hub** - send the file to all the computers that are connected to the same network. **\*CABLES\*** 1\. Automatic Cable 7. Coaxial Cable 2\. Console Cable 8. Serial DCE Cable 3\. Copper Straight-Through Cable 9. Serial DTE Cable 4\. Copper Cross-Over Cable 10. Octal Cable 5\. Fiber Cable 11. IoT Custom Cable 6\. Phone Cable 12. USB Cable **\*CONNECTIVITY\*** **ISP (internet service provider)** - provides the link between the home network and the internet. **== ISP SERVICES ==** \- web hosting \- FTP (file transfer protocol) hosting \- application and media hosting \- technical support \- voice over IP \- POP (point of presence) internet access \- Equipment co-location **\*STRUCTURES\*** **cable** - typically offered by cable television service providers, the internet data signal is carried on the same coaxial cable that delivers cable television. **DSL (digital subscriber line)** - provides a high bandwidth, always on, connection to the internet. **satellite service** - is a good option for homes or offices that do not have access to DSL or cable. Satellite dishes (see figure) require a clear line of sight to the satellite and so might be difficult in heavily wooded areas or places with other overhead obstructions. **cellular** - internet access uses a cell phone network to connect. Wherever you can get a cellular signal, you can get cellular internet access. **dial-up telephone** - an inexpensive option that uses any phone line and a modem. To connect to the ISP, a user calls the ISP access phone number. **\*WIRELESS MOBILE NETWORK\*** **wireless networks** - are computer networks that are not connected by cables of any kind. ex. smart phones, laptops, tablets, etc. **\*MOBILE NETWORKS\*** **mobile networks** - is a telecommunication network that provides services via radio signals for mobile phones. **GPS (global positioning system)** - uses satellites to transmit signals that cover the globe. **Wi-Fi (wireless fidelity)** - transmitters and receivers located within the smartphone enable the phone to connect to local networks and the internet. \- networks are usually privately owned but often provide guest or public access hotspots. **NFC (near field communication)** - is a wireless communication technology that enables data to be exchanged by devices that are in very close proximity to each other, usually less than a few centimeters. ex. RFID **\*HOME NETWORKS\*** **ethernet** - ports connect to the internal switch portion of the router. These ports are usually labeled "Ethernet" or "LAN", as shown in the figure. **internet** - port is used to connect the device to another network. The internet port connects the router to a different network than the Ethernet ports. **category 5e** - is the most common wiring used in a LAN. The cable is made up of 4 pairs of wires that are twisted to reduce electrical interference. **coaxial cable** - has an inner wire surrounded by a tubular insulating layer, that is then surrounded by a tubular conducting shield. **fiber-optic cable** - can be either glass or plastic with a diameter about the same as a human hair and it can carry digital information at very high speeds over long distances. \- have a very high bandwidth, which enables them to carry very large amounts of data. **== OSI AND TCP/IP ==** **OSI (Open Systems Interconnection)** - model is a conceptual framework used to understand and standardize the functions of a networking or telecommunication system. **OSI Model Layer** **1.Physical Layer** - Function: Handles the physical connection between devices, including the transmission and reception of raw binary data over a communication medium (cables, radio waves, etc.). - Examples: Ethernet cables, fiber optics, and wireless transmission. **2.Data Link Layer** - Function: Responsible for node-to-node data transfer and error detection/correction in the physical layer. It also handles MAC addressing and ensures data is sent to the correct hardware. - Examples: Ethernet, Wi-Fi (MAC layer), switches. **3.Network Layer** - Function: Manages the routing of data between different networks by determining the best path for data to travel. It deals with logical addressing (IP addresses) and packet forwarding. - Examples: IP (Internet Protocol), routers. **4.Transport Layer** - Function: Provides reliable data transfer between systems, ensuring data arrives in order and without errors. It controls flow, error correction, and re-transmission of lost data. - Examples: TCP (Transmission Control Protocol), UDP (User Datagram Protocol). **5.Session Layer** - Function: Manages sessions or connections between applications. It establishes, maintains, and terminates communication sessions between computers. - Examples: NFS (Network File System), RPC (Remote Procedure Call). **6.Presentation Layer** - Function: Transforms data into the format required by the application layer. It handles encryption, compression, and data conversion (such as translating data between different character encodings). - Examples: SSL/TLS (for encryption), data encoding like JPEG, ASCII. **7.Application Layer** - Function: This layer interacts directly with end-user applications, providing services like email, file transfer, and web browsing. It\'s where the user's data is created and consumed. - Examples: HTTP, FTP, SMTP, DNS. **TCP/IP (Transmission Control Protocol/Internet Protocol)** - is a set of communication protocols used for interconnecting network devices on the internet. It breaks down the communication process into distinct layers, each with specific functions, and is the foundation of the internet. **1. Network Interface Layer (Link Layer)** - Purpose: Handles the physical transmission of data between devices on the same network. - Key Functions: It manages protocols for data transfer over physical networks like Ethernet or Wi-Fi. This layer is responsible for how data is physically sent (e.g., over a cable or wireless). - Examples of Protocols: Ethernet, Wi-Fi (IEEE 802.11), ARP (Address Resolution Protocol). **2. Internet Layer** - Purpose: Manages addressing, routing, and forwarding data across networks (to ensure data gets to the right destination). - Key Functions: It encapsulates data into packets, assigns logical addresses (IP addresses), and routes data between devices across different networks. - Key Protocols: IP (Internet Protocol), ICMP (Internet Control Message Protocol), IGMP (Internet Group Management Protocol). **3. Transport Layer** - Purpose: Ensures reliable data transfer and controls how much data is sent. - Key Functions: It manages error checking, data flow control, and retransmission of lost data. This layer is responsible for making sure data arrives in order and without errors. - Key Protocols: - TCP (Transmission Control Protocol): Ensures reliable, connection-oriented data transmission. - UDP (User Datagram Protocol): Provides faster, connectionless data transfer without guaranteeing delivery. **4. Application Layer** - Purpose: Provides network services to end-users and applications. - Key Functions: It defines the protocols for specific network communication like web browsing, email, file transfers, etc. - Examples of Protocols: HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), SMTP (Simple Mail Transfer Protocol), DNS (Domain Name System). **== ACCESS LAYER ==** **MAC** - address is a string of characters that identifies a device on a network. It's tied to a key connection device in your computer called the network interface card, or NIC. - Some well-known manufacturers of network adapters or NICs are Dell, Belkin, Nortel, and Cisco. **The Organizationally Unique Identifier (OUIs) for some well-known manufacturers are:** - The OUIs for some well-known manufacturers are: - Dell: 00-14-22 - Nortel: 00-04-DC - Cisco: 00-40-96 - Belkin: 00-30-BD **Ethernet Frame** - **Preamble (7 bytes):** A sequence of bits that helps synchronize communication between devices. It consists of alternating 1s and 0s, which allows the receiving device to recognize the start of the frame. - **Start Frame Delimiter (SFD) (1 byte):** A specific pattern (usually 10101011) that indicates the end of the preamble and the start of the actual frame data. - **Destination MAC Address (6 bytes):** The unique hardware address of the device intended to receive the frame. This ensures that the frame reaches the correct destination. - **Source MAC Address (6 bytes):** The unique hardware address of the device sending the frame. This allows the recipient to know where the frame came from. - **EtherType/Length (2 bytes):** This field indicates the type of protocol encapsulated in the payload (EtherType) or the length of the payload in bytes. Common EtherTypes include 0x0800 for IPv4, 0x0806 for ARP, etc. - **Payload/Data (46 to 1500 bytes):** The actual data being transmitted. The minimum size for the payload is 46 bytes, and if the data is smaller, padding is added. The maximum frame size for Ethernet is 1500 bytes, not including headers and trailers. - **Frame Check Sequence (FCS) (4 bytes):** A cyclic redundancy check (CRC) value used for error checking. It allows the receiving device to verify the integrity of the frame. If the FCS doesn't match, the frame is discarded. **Encapsulation** - is a process by which a lower-layer protocol receives data from a higher-layer protocol and then places the data into the data portion of its frame. - in networking is the process of wrapping data with protocol information at each layer of the OSI model. **Port** - is a logical address of a 16-bit unsigned integer that is allotted to every application on the computer that uses the internet to send or receive data. - Whenever any application in one computer sends data to another application of a different computer then it sends using IP Address and MAC Address but how does our computer know that this data is for a specific application and this data is sent by any specific application? There comes the concept of Port. **Parts of an IP** **Subnet Mask** - Defines the division between the network and host portions of an IP address. It specifies how many bits are used for the network address and how many are used for the host address. **IP Class** - **Class A (0.0.0.0/8 to 127.0.0.0/8)** - Designed to support extremely large networks with more than 16 million host addresses. Class A used a fixed /8 prefix with the first octet to indicate the network address and the remaining three octets for host addresses (more than 16 million host addresses per network). - **Class B (128.0.0.0 /16 - 191.255.0.0 /16)** - Designed to support the needs of moderate to large size networks with up to approximately 65,000 host addresses. Class B used a fixed /16 prefix with the two high-order octets to indicate the network address and the remaining two octets for host addresses (more than 65,000 host addresses per network). - **Class C (192.0.0.0 /24 - 223.255.255.0 /24)** - Designed to support small networks with a maximum of 254 hosts. Class C used a fixed /24 prefix with the first three octets to indicate the network and the remaining octet for the host addresses (only 254 host addresses per network).