Network Topologies & Elements

• Cisco is being studied

Network Topologies

• WAN (internet) is mentioned
• Access types include public, private, and extremes
• Topology refers to the physical arrangement and how devices are connected logically
• Bus topology involves all devices connecting to a central cable
• Bus topology uses copies for communication and does not offer privacy
• Bus topology is faster
• Ring topology involves devices connected in a circular fashion
• Ring topology can be slow due to a long amount of time to transmit
• Star topology is like an extended star arrangement, often using a hub
• Mesh topologies can be full or partial
• Full mesh means every device is directly connected to every other device, implying privacy
• The number of connections in a direct mesh is calculated by n(n-1)/2
• N represents the number of devices in the network

Network Elements and Mediums

• Network elements are PCs, laptops, cameras, and are connected to the network as end devices
• Connecting devices are hubs, switches, and routers, acting as intermediaries
• End devices are clients
• Servers are higher speed computers
• Switches are connecting devices, but not servers
• Mediums include cables such as copper, coaxial (BNC or BNC-T), fiber optic (lumineux/light)
• Fiber optic cables contain 2 or 4 wires
• Cat 5 cables have 8 wires and 4 pairs
• Wires are orange, blue, green, and brown
• Speeds are 10Mb/s and above
• Connectors are RJ45 clips

Data Transmission and Cabling Standards

• Data is sous forme electrique, then electrical
• Cat 5e cables have speeds of 100Mb/s
• Cat 6 cables have speeds of 1000Mb/s which is 1Gb/s
• Cat 6a cables have speeds of 16b/s
• Cat 7 cables have speeds of 10 Gb/s
• STP (shielded twisted pair) cables are used

Network Protocols and Communication

• Communication involves a medium cable
• Communication has a source (A) and destination (B)
• Communication from A to B follows and ISO standard, using 7 layers as a reference model called OSI
• There are 7 layers of the OSI model
• The 7 layers are, in descending order, application, presentation, session, segmentation, network, transport, and data-link
• Application layer is the user layer
• Presentation layer translates to the network
• Session layer continues sending data
• Segmentation layer is for addressing and finds the best path
• Network layer handles addressing and routing
• Transport layer transports data
• Data-link layer handles error detection
• Physical layer involves the medium (fiber, wireless)
• Each layer has its service, but protocol can change
• Decapsulation happens ascending up the stack
• Data goes through segmentation with a packet and frame
• EPDUS protocol has a destination unit

TCP/IP Model vs. OSI Model

• TCP/IP model has 4 layers rather than 7
• The 4 layers are application, transport, network, and network access
• Layers 7-6-5 of the OSI maps to application
• Layer 4 of OSI maps to transport
• Layer 3 of OSI maps to network
• Layers 2-1 of OSI maps to network access
• Addressing in the Network layers is required
• MAC addresses are fixed and BIA (burned-in addresses)
• MAC addresses cannot be changed and use a flat addressing scheme
• MAC addresses are unique per layer
• Format for MAC address is 12 hexadecimal digits
• Layer 3 addresses are not fixed and hierarchical
• Layer 3 addresses can be changed and are unique, configurable
• Format for IPv4 addresses is 4 dotted decimal numbers
• A valid IP address example is 192.168.55.16
• An invalid IP address example is 304.16.54.11
• The maximum number for any decimal is 255
• Transport layer uses a decimal wind or port number for addressing

Protocol Models and Devices

• Every data transmission requires a port number
• MAC addresses have local significance
• IP addresses are universal
• Repeaters and Hubs are equipment of the physical layer
• Switches are devices from Layer 2 (Data-Link)
• A multiport bridge is a switch
• MAC address is used for each

Routers and Switches

• Routers operate at Layer 3
• Switches operate at Layer 2
• MAC addresses relate to speed and destination
• Routers function at the network level
• Hubs operate at the physical layer

Switch and Router Configuration

• Switches are self-learning and have more ports (software MAC)
• Routers have fewer ports (software IP)
• PCs need a keyboard/mouse, screen, CPU, RAM, BIOS, ROM, and HDD(hard disk drive)
• Switches/Routers need no screen/mouse, no keyboard, CPU, RAM, ROM POST (IOS), NVRAM, flash (IOS) memory
• ROM is Read Only Memory for BIOS (tsayev programs zghar)
• Switches ROM loads to HDD then IOS and finally RAM
• Routers run on ROM which loads to flash memory and then to RAM
• Configure using Switch/computer serial port

Cisco IOS Configuration

• Console cables attach to console ports
• Putty is a program to connect to Cisco
• Router = switch
• The is a command line interface (CLI) that is Mech GUI(graphical)
• Switch > enable puts you in priviledge mode- shows the mode
• Then switch # configure terminal allows global configuration
• Switch(config)# hostname [Host Name] allows for renaming
• You need to create a password with line console 0 and the password command
• Type login and exit
• There are 2 levels of security [enable password]
• Save the configuration with "copy running-configuration startup configuration"
• This saves to the NVRAM

Cisco IOS Commands

• "switch>enable then switch >en"
• Switch # configure terminal then conf t
• 2)conf t
• 3)hostname (name)
• 4)line console 0
• 5)password (password)
• 6)login
• 7)enable password (password)
• 8)exit
• 9)copy run start
• 10)banner motd #[Message here]#
• press Tab to auto fill

Command Line Interface Continued

• Commands require a password, banner, and enable secret,
• Use service password-encryption.
• Clear commands via no hostname.
• Show Run Command:*
• Shows "line console", password", "enable password".

Identifying IP Addresses

• "IP Windows" and GUI
• Located on the network card in the "control panel adapter settings, then IP address"
• Then obtain your "IP address"
• Obtain your "IP address el computer" automaticaly from DHCP Server
• Men wara server
• "MAC byeje maffour 3al router, PC..."
• "Port Machine brezti yeha"
• "Ip - ana fine Zetto / Automaticly"
• You can find the "HAC" Addien by Router
• use Switch and DHCP Server
• At command prompt from cmd use "C:/ ipconfig (enter) deghre bi elma chou up" to get "HAC addien"

Physical Layer

• Uses physical cables for encoding and signal transmissions (electric, optics, electro-magnetic waves) to "eliminate confusion"
• If no connection, then there is "no electricity"
• bnett 5V bayneton
• uses Electric circuits
• Signals need to provide synchronization, and it needs to have time
• "time of a Bit"
• Error detections are possible in the "Ist layer blaste hints"

Data Link

• "haye maszouté 3an error" (is not ok with errors
• needs parity to be one or even

Networking Essentials

• Use the terms "yemken & yłbadalo" for addresses
• signals need Ma elo mazna (cactora) " that encoding makes data bitghayar bars bleble" Cayer & tezmal encoding "
• "Signaling & encoding 010000001 time"
• "pariad bhet 5V" the Signalisation

General Concepts in Physical Layer

• "Jual & men loufa bt roam +V tayê - V "
• Can pass yale be non
• Uses a "metel Cable0101000010000"

Services Data Link Layer

• The "Servies I Maddening "
• It is the responsibility of the medium for:
  • acces control (MAC)
  • Error detection" (CRC)
  • Protocol
  • "bthakem bl physic layer" Ethernet

Data Link Protocol

• yale ela be date, :Ethernet (layer &)Medium ltonza breuhtelef
• Data: 010011TO is used by polysonme
• used to "byeshteghel me MAC addien (12 hexa)"

How Devices Connect

• Data can be sent with A B or C, use the "destination blejas tezmel calal w byellaba reast tene2
• with CRC this "3bizarno bi awal reast Ira ma teles nafso yezne fi Cerror" : (The esma el faizz)
• use "laula ken star map deze lethernet" using "esma CSMA/CD it comdetect Multiple access"

Data Link

• The "sewives (on not clause)" cannot be changed
• has: "protocal may vario"and Addressing error detection"