ICT 10 | 2nd Quarter 2.pdf

ICT 2nd Quarter NETWORKING DEVICES hardware devices employed for establishing a connection of fax machines, computers, printers, and other electronic equipments with that of the network information can be transferred in a quicker and exact approach across similar or various kinds of networks...

ICT 2nd Quarter NETWORKING DEVICES hardware devices employed for establishing a connection of fax machines, computers, printers, and other electronic equipments with that of the network information can be transferred in a quicker and exact approach across similar or various kinds of networks Network Device Types Range of Equipments 1. Important Networking Elements — established communication with other network elements 2. Hybrid Components — found in network border or network core 3. Hardware/Software Components (Add-ons) — mounted on the connection edges of various networks Types of Network Devices Hubs collective connection of networking devices (bulk distribution of information) functions as a repeater (boosts poor signals that lost strength after travelling long distances on cables) simplest network device used for device connections (connects LAN devices using similar protocols) employed with both analog and digital data by configuring settings to format the incoming information expensive; obsolete now due to newer network devices ◦ biggest disadvantage — problems with storage capacity due to collective connection ◦ MTO Hubs — “made-to-order” Classification of Hubs (Based on Usage Development) 1. Active Hub (busiest) ◦ examines/filters information transmitted to connected device ◦ employs store technology (monitors information before transmission) ◦ manages distribution and direction of remaining packet ◦ prioritizes what packet has to be transmitted initially ◦ resolves issues based on damaged products 2. Passive Hub ◦ distributes signals received from ports without processing the signal ◦ finds bugs and defective hardware ◦ has 10Base-2 port and RJ-45 connectors that have connections with every local area network tool 3. Intelligent Hub ◦ has more benefits; enhances performance of LAN connection ◦ finds and resolves defects easily through management data corrected by hub ◦ finds centralized management tool to know about the network that runs out of the device in finding minimal operating devices ◦ good for extended businesses Switch more creative functionality than hubs multiport device that enhances network performance knows hardware addressing of incoming packets and transmits information to the proper destination supports restricted routing data regarding nodes in internal network and permits connections for systems (such as routers and hubs) stores MAC Address (Media Access Control; physical address of every device) Router “Gateway of Network” transmits data packets/traffic across various networks chooses best path in the transmission to reach destination faster located at gateways (where there’s a network connection) for connection, must have minimum of two networks: LANs or LANs & WANs stores IP Address (Internet Protocol) ◦ parameter — configuration settings; found at the back/bottom ◦ gateway — application where parameter may be adjusted Hub Switch Router creates network creates network connects networks detects physical connections detects MAC addresses detects IP addresses copies data to all ports directs data to intended port only directs data to intended network then to intended device doesn’t filter information filters information filters information exchanges within LAN only exchanges within LAN only exchanges outside of LAN Bridge divides larger networks into smaller sections located between two physical network segments and manages data flow between the two looks at MAC Address of devices connected to each segment in order to forward data (if destination is on another interface) or block it from crossing (if destination is on interface it came from) Types of Bridges 1. Transparent Bridge ◦ devices on network are unaware of its existence ◦ only blocks or forwards data based on MAC Address 2. Source Route Bridge ◦ used in Token Ring Networks ◦ entire path to be taken by packet through the network is embedded within packet 3. Translational Bridge ◦ converts one networking data format to another (ex: Token Ring to Ethernet and vice-versa) Network Card (Network Interface Card/NIC) enables computers to connect to network Modem (Modulator-Demodulator) converts digital signals generated by computers into analog signals that can travel over phone lines can be internal add-in expansion cards or external devices that connect to the serial/USB port of system Transceiver both a transmitter and a receiver of signals places signals onto network media and detects incoming signals traveling through same wire ◦ chip transceivers — small, inserted into system board or wired directly onto circuit board ◦ module transceivers — external to network; functions similar to other computer peripherals or can function as stand-alone devices Firewall  either hardware or software; controls access to organization’s network protects data and resources from outside threat provides following protection features: ◦ controls access to Internet and network ◦ secures data traffic for incoming and outgoing connections ◦ alerts suspicious activity ◦ active control of applications ◦ privacy protection ELEMENTS OF A COMPUTER NETWORK Data Network critical asset for many industries connects users and enables them to access various resources cannot function without the four elements Four Basic Elements 1. Hardware 2. Software 3. Protocols 4. Connection Medium Computer Network shares common devices, functions, and features (including servers, clients, transmission media, shared data, shared printers, other hardware/software resources, network interface card, local operating system, and network operating system) components comprise both physical and software parts for installation ◦ hardware components — server, client, peer, transmission medium, connecting devices… ◦ software components — operating system, protocols… Communication process of passing information from one person to another basic elements: ◦ Message Source — sender/origin of message ◦ Encoder/Decoder — sends messages directly to receiver with encoding ◦ Channel — sends signal across to receiver ◦ Message Destination — final recipient of message sent from the source Sender Device used for communication between devices that have access to the network sends information Receiving Device used for communication between devices that have access to the network receives information The servers and clients are known as the “End Devices”. Servers (Receiving Device) holds shared files, programs, and the network operating system provides access to network resources to all users of the network has many different kinds Clients (Sender Device) “the customers (users) of the network”, as they request and receive services from servers accesses and uses the network and shared network resources typically a personal computer Transmission Media sometimes called “Transmission Medium Channels, Links, or Lines” facilities used to interconnect computers in a network (such as twister-pair wire, coaxial cable, optical fiber cable…) Transmission Rate/Bandwidth how fast information can be transmitted over channel measured in bits per second (bps) Transmission Directional Capability direction in which information can be transmitted over channel ◦ simplex — one direction ◦ half-duplex — both directions one at a time ◦ full-duplex — both directions simultaneously Guided Media/Line Based Media (Wire Line) several kinds: twister-pair wire, coaxial cable, optical fiber cable ◦ wireless media — no physical wire along which information travels (ex: radio, microwave, satellie, mobile networks) Signal Type either analog or digital ◦ analog signals — continuous; wide range of values ◦ digital signals — discrete and binary; only two values Message information/data that travels over medium Shared Data Shared Printers & Other Peripherals provided by file servers to clients hardware resources provided to users of the network by servers e-mails, data files, printer access programs, etc. software, printers, data files, etc. Network Traffic Concepts measure bandwidth as the amount of data in bits/bytes that dan pass within one second most basic unit of measurement for bandwidth is in bits per second THE OPEN SYSTEM INTERCONNECTION MODEL (OSI Model) foundation for all networking technologies allows current and future networking platforms to interconnect and work seamlessly ensures that data/information are exchanged across all networks regardless of hardware, software, or transmission platform identifies seven essential services wherein data transmission takes place each of these services can stand alone; created in the most simplest code to avoid complications History of the OSI Model defined in raw form in Washington, DC on February 1978 by Hubert Zimmerman of France refined but still draft standard was published by the ISO in 1980 Advantages of OSI Model Helps Users & Operators of Computer Networks… 1. determine the required hardware and software to build their network 2. understand and communicate the process followed by components communicating across a network 3. perform troubleshooting by indentifying which network layer is causing an issue and focusing efforts on that layer Helps Network Devices Manufacturers & Networking Software Vendors… 1. create devices and software that can communicate with products from any other vendor, allowing open interoperability 2. define which parrs of the network their products should work with 3. communicate to users at which network layers their product operates Upper Layers converts any information understandable to us humans that needs to be transmitted into usable data that could be transported through any medium (wires, air waves, fiber optics...) 1. Application Layer applications/programs used to create, send, receive, and read email with could be your browser (Internet Explorer, Firefox, Chrome, Safari…) or any email client (Outlook, Outlook Express, Thunderbird, Mail…) ◦ Simple Mail Transfer Protocol (SMTP) ◦ File Transfer Protocol (FTP) 2. Presentation Layer data conversion and translation; ensures data will be readable by receiving station Functions of Presentation Layer a. Character Code Translation ◦ converts ASCII (American Standard Code for Information Exchange) to EBC DIC (Extended Binary Coded Decimal Interchange Code) ◦ ASCII — human-readable data format (ABCs and 123s) ◦ EBC DIC — understandable by computer/machine (1s and 0s) b. Data Conversion ◦ converts formatted text created in the application layer into a data stream or bit order format ◦ identifies when or where a CR/LF (Character Return/Line Feed) has been inserted, whether the numbers to be transmitted need to be in integer or floating point format c. Data Compression ◦ identifies and tags attachments, then applies appropriate compression for it to be transmitted through the network at more manageable units of data d. Data Encryption/Decryption ◦ translator between networks and application layer ◦ allows sending and receiving of information regardless of device, operating system, or application software ◦ case of passwords for logging into email and other security-related data 3. Session Layer determines how two devices/machines establish a connection deals with how connection is maintained and managed, especially for handling errors identifies protocols/set of rules that could be followed by both devices, end to end Lower Layers mechanics of how devices/machines communicate and transfer data from one machine to another  how data is transported throughout network more closely related to the physical attributes of a network 4. Transport Layer converted data is divided into “segments”; segmentation allows for data to travel through networks as quickly as possible against all traffic adds a “segment header” for the protocol information ◦ protocol information — necessary to ensure that receiving device/machine can communicate reliably with source device/machine ◦ encapsulation — addition of different headers for each data segment that’ll run throughout the remaining layers 5. Network Layer adds a “network header” to the “packet” puts in logical addressing and routing information for data to arrive at right destination ◦ routing information — how data negotiates through traffic in networks and determines the best path 6. Data Link Layer adds a “frame header” to the “frame” last step in encapsulation process; data segment is all ready and packaged for transport contains MAC address of source computer and router/computer adjacent to it ◦ frame header — contains information regarding how data is communicated through adjacent nodes/ machines in the network before it finally reaches its destination ◦ Media Access Control (MAC) — physical unique identifier of any network device such as a Network Interface Card (NIC) or a wireless NIC; embedded on device itself during manufacture, permanent and no two devices can have the same address 7. Physical Layer actually sends the data carrying the information wanted to convey involves mechanical/electronic means of transmitting data; tangible like the Application Layer refers to medium of transmission (wires, optic cable, radio signal…) and how it’s physically connected to devices sees data as string of bits (1s and 0s) Decapsulation happens after information reaches destination device, where each segment runs through the same set of layers in reverse order once segments are received, presentation layer reassembles data stream and converts it back to human readable form each segment is stored in destination device NETWORK ADDRESSES more commonly known as Internet Protocol (IP) address a set of numbers called “octets” that identifies any network device which will be referred to as a host in a network IP Address uniquely identifies a host on a TCP/IP network, expressed in dotted decimal format doesn’t refer to any specific geographical location, just points to what particular network group a specific host belongs to made up of 32 binary bits divisible into a network portion and host portion with the help of a subnet mask ◦ 32 binary bits are broken into 4 octets (1 octet = 8 bits)  ◦ each octet is converted to decimal and separated by a period ◦ example: 172.16.81.100 two parts: ◦ Net ID — first three high order bits of the first octet; categorized into five different classes ◦ Host ID — last number; identifies host of network Reserved IP Address certain host addresses are reserved and cannot be assigned to devices on a network has binary 0s in all host bit positions reserved for the network address has binary 1s in all host nit positions reserved for the broadcast address ◦ gateway — node that serves as the access point on a network IPv4 IPv6 deployed 1981 deployed 1998 32-bit IP address 128-bit IP address 4.3 billion addresses — addresses must be reused 340 undecillion addresses — every device can and masked have a unique address numeric dot-decimal notation alphanumeric hexadecimal notation DHCP or manual configuration supports autoconfiguration the one we’re accustomed with the one to replace IPv4 one day Subnet Masks sets or assigns a logical network within a network borrows certain bits of the IP address that’s set for hosts depending on network class Dynamic Host Configuration Protocol (DHCP) system built in every server operating system that allows hosts to join IP-based networks with minimal manual configuration assigns an IP address from a pool allotted to i when a host connects to a network, it broadcasts a signal alerting all other hosts in the network Three Key Values of the DHCP Service 1. operation tasks reduced — network administrator no longer needs ro manually configure each client before it can use the network 2. IP addressing plan optimized — addresses no longer being used are freed up and made available to newcomer clients 3. user mobility easily managed — administrator doesn’t need to manually reconfigure a client when its network access point changes Configuring Devices Network Configuration process of setting a network’s controls, flow, and operation to support the network communication of an organization/network owner incorporates multiple configuration and setup processes on network hardware, software, and other supporting devices and components allows a system administrator to step up a network to meet communication objectives involves following tasks: ◦ Router Configuration — specifies correct IP addresses, route settings, etc. ◦ Host Configuration — sets up a network connection on a host computer by logging the default network setting such as IP addressing, proxy, network name, and ID/password ◦ Software Configuration — any network-based software like an intrusion detection system (IDS) is allowed access and provided with the appropriate credentials to monitor network traffic Importance of Network Configuration 1. automated data tracking and reporting, allowing administrators to spot any configuration changes and potential threats or issues 2. easy way to make bulk changes, such as a blanket password change in a situation where passwords are compromised 3. swiftly roll back network settings to a previous configuration 4. reduced downtime, thanks to increased visibility and ability to quickly identify changes 5. streamlined maintenance and repair of network device (physical/virtual) and connections 6. relaunch device when it fails, thanks to centralized storage management of device configurations Router/Gateway with its DHCP function, it’s responsible for assigning an IP address to all network devices/hosts connected to the network ensures that no device will create a conflict against any other device in the network; handles security for the network allows or blocks other computers from joining its network through settings and configuration ◦ default IP address is the key to accessing the configuration screen of a router (default: 192.168.x.x.) ◦ standard security measure default administrator’s password: “admin” ◦ hard reset router’s settings back to original factory settings; administrator’s username and password (set of information easily googled in the absence of a manual) is reverted back to the original default Steps to Verify the IP Address of a Router 1. Using a mouse, move pointer to upper right corner to pull out the charm bar. 2. Click on the “Search” icon. 3. On the search box, type “cmd.” This should open up a black window called the “command console.” 4. In the command console, type “ipconfig.” 5. Using your keyboard, press the “Windows” key. 6. Type “cmd.” Press the “Enter” key. 7. Repeat steps 3-4. 8. The IP address indicated by the “Default Gateway” is the IP address of your router. Gateway combination of modem and router carries an “external” or “Internet” IP address and an “internal” IP address modem part will assign an IP address assigned by your ISP router part will have its own internal IP address for local routinh Common Parameters 1. IP Address of the Router IP address by which the user interface could be accessed to set it up ◦ form: 192.168.x.x 2. Subnet Mask default: 255.255.255.0 ◦ 192.168.x.x IP address — reserved local Class C IP address; enables the router to have a pool of 252 IP addresses that its DHCP can assign and use 3. DHCP usually a toggle switch or check box that you can tick on and off allows any host connected to it to “obtain IP address automatically” some routers can set IP address range the DHCP can assign, limiting number of connections 4. DNS “Domain Name Server Setting”; allows hosts on network to use the DNS assigned by ISP know your ISP’s alternate DNS address especially when troubleshooting connectivity issues ◦ default: 0.0.0.0 Wireless Router Additional Parameters 5. SSID “Service Set Identifier”; wireless or WiFi network name some routers allow you to switch off broadcasting of SSID for added security 6. Security/Encryption all routers have provisions to encrypt log-in credentials and data being transmitted through the network ◦ WEP — Wired Equivalent Privacy ◦ WPA — Wi-Fi Protected Access 7. MAC Address Filtering form of security enter MAC addresses of computers that’ll be connected to the network on a list that the router maintains router saves the information and won’t allow any device not included in its list to connect to it ◦ blacklist — block ◦ whitelist — allow Sabihin na lang po sakin if may mali o kulang.