Networking

• Central processing Unit
• Heart of it 
• Performs arithmetic
• Has ALU,control Unit, register storage, memory

• Arithmetic Logic Unit
• Does calculations with what the control unit sends it

• Controls ALU, memory
• Performs flow of data to different compartments resulting in processed data

• Most expensive and fastest memory
• Not a lot on the CPU
• CPU performs on data in registers and if not there then goes to cash levels, then memory, then 2nd storage and brings it back up to register

• Least expensive and slowest memory
• Where everything is stored when computer not on, and has the most space

• The Primary memory that holds RAM
• Faster than secondary storage

Process of looking for something on a disk (the hardrive)

• Take information from the secondary storage and witch with something from main memory, until you have the information you need
• Main memory only has so much room so must swap information so main isn't over loaded

Connects to secondary storage/harddrive

• User provides info
• Mouse, keyboard

• Computer provides info back
• Monitor, printer

Allows networks of computers to talk to each other

This consists of the moment you press the on button to you screen showing up

• Which order computer looks for OS and in CMOS
• CPU->BIOS->POST->CMOS->MBR->Execute OS

• Fetch (instruction)
• Decode (instruction)
• Execute (instructions)

• Goes to BIOS chip
• Holds permanent instructions to execute

• Basic input/output system
• Flash memory which holds 1st instructions for CPU

• 1)CPU runs POST
• Power On Self Test
• If RAM is good, CPU good then moves on
• If error, then generates beeps according to number of problems

• Power On Self Test
• Sanity, work ability of CPU and Main memory

• Operating System
• On a DVD or Hard drive
• Self of instructions ( a program)

• On mother board
• Another memory and holds configuration data (current time, boot process)
• Tells where to look for OS

• Master Boot Record
• Has as pointer or address to where the OS is on the device
• Gives instructions in Sector 0 of disk
• If MBR damaged or lose Sector 0, then OS won't boot
• If 2 OS, MBR has another component to ask which one to run

• Where all major components are housed
• CPU Socket is main part

Allow to connect things to it

Dynamic Ram

Process Graphics

Connect devices such as network communication

Integrated into the motherboard

• When system is out, no more memory
• Called volatile memory
• Cash, register, ram (main)

• Synchronize activity on motherboard
• Frequency of activity is measured in MHZ
• Input in CPU that allows cloce to operate 

Number of cyles per second

• Dip Switches
• Hard-wired instructions in 1 and 0
• The different combinations accomplish different tasks you can't do with software

• System of pathways used for communication
• Bunch of wires (number of wires-bit bus)
• Talks to CPU by putting info in 1 and 0
• CPU communicates by putting electrical activity through bus

• Address bus: carries address line of where it is going
• Data bus: caries the data that will go in the address line
• Control bus: is the clock and weather is is to read or write (read =1, write =0)

• Are in the power of 2
• 2^10 = 1024 = 1K
• 2^31 = 1K*1K*1K*2 = 2 gig

At any time, exchange 64 bits back and forth

How many address lines therer are 

• Temporary
• secondary
• Master
• Serial ATA
• SCSI

• Hardviees where it is for permanent
• Stay when power off 

CPU is called to do something, so it finishes it current task then interrupts and handles the request

Slow devices interact with CPU with interrupt request

• Direct memory access
• Fast devices need to send straight to memory
• Call CPU buses which is direct access so CPU gram buses 
• Used DMA channel to ask for access to it as well as returning it

• DMA controller
• Has to do with control of other devices

• DRAM Refresh (dynamic ram)
• Leaky so every so often it refills which is done through DMA and allows it to just be done without permission

• Local Area Network
• Building block for internetworks
• Connected by routers

Network of 100 or more computers

• Metropolitan Area Network
• Spans metropolitan area

• Wide Area Network
• Internetworks of multiple MANs

Global internetwork

• Network Interface Core
• Converts information to 1 & 0
• One end connect to network, other end connect to motherboard where information comes and gets transmitted

• Establishes a connect
• Cords from two different ports connect to hub which connects the 2 computers
• Switch is an intelligent hub
• All it does is repeat information and who from, where going and repeats
• Repeats to all NIC's connected to it

Cables have 4 pairs of wires used for transmission and interception which carries an electrical pulse

• Nothing but a Jack
• Computers connect to jack, connects to patch panel and those both connect to the HUB to connect two computers

• AKA: physical address, hardware address
• 48 Bit MAC address associated with NIC and every single one is unique

• 4 bits together
• 8 together make a byte

8421 and add them up where 10 = A and goes to F

• NIC to talk to another NIC must create a Frame
• Destination: Source: Data: CRC
• CRC is cyclic redundancy code or Frame Check Sum: helps recognize if something goes wrong. Creates redundant piece of information and checks if they match

• Address resolution protocol
• Identifying mac address of computers by name
• Each NIC makes a ARP Cache and fills it will the Name: Mac address of the other computers on the network
• Only a local area techniques not WAN
• Routers filter out ARP

• 1) Gets Data (x)
• 2) Sending Workstation (x) creates a frame
• 3) Consults ARP cache and translates destination to mac address and CRC check if good or bad
• 4) Sends out bits to hug and hub repeats info
• 5) EAch other computer looks at 48 bits and if not match, then doesn't listen
• 6) Destination takes it and data gets transported up

• Computer sends out a broadcast by creating an ARP request Frame with destination FFFFFF to all those to listen and asks what is (z) mac address
• Hub repeats to all computers and the destination creates a response to fill the ARP cache

• ID to take beyond the LAN
• 32 bit address or ID separated by decimals 
• 765433210 in power of 2 so really
• 128.64.32.16.8.4.2.1 where 255 is the max with all 1's

• Network Layer
• Link Layer
• Physical layer

• Responsible for inter network transport over routers
• IP packets
• Static: IP address permanent and only yours
• Dynamic: Provided by service and get for a while

• Operating on LAN
• Responsible for transport over single link (LAN)
• NIC FRAME

• Responsible for transport of bits
• Trasiever/Receiver that connects to medium (wire)

• 1 computer communicated to hub by sending frame
• Hub repeats to everyone
• Workstations look at destination and see if for them
• Only a repeater and is at lowest physical layer of network protocol

• Intelligent
• Operates at link layer 
• Knows what it has in switch table (prorts, MAC)
• More than 1 line of communication can be established
• Understands frame

• Has MAC addresses and the Ports they are located on
• Learning Process: is where it learns the MAC addresses and ports form traffic
• Forward and filter: If still not have one, then forward to everyone like a hub to learn it

• Data, Dest IP, Source IP come to network layer
• Dest IP uses ARP cache and network makes a PACKET with dest mac, source mac, data
• Packet goes to link layer and is inserted in data portion of frame
• Frame moves physical network and broken to 1's and 0's and get's sent across
• Comes in and Link layer check sCRC and if good then Destructs frame
• Sends packet up and data taken out and moved up

• Set a certain portion of the IP address to be the network
• Represent with 255 and the rest 0's
• This is called subnet part of address
• If they have the same mask, it doesn't mean they are on the same network
• 255.0.0.0 = 254 unique addresses
• 255.255.0.0 = 2^16 = 64 thousand
• 255.255.255.0 = 2^24 = 16 mill subnets

• Mask applied to Dest IP
• Mask applied to Source IP
• If same subnet then in same LAN and goes to dest

• Apply mask and if not same then goes to default gateway
• The Dest MAC is the routers but the source stays who it's from
• Need this because outside of lan

• Like a postoffice
• Default gateway is the routers IP 
• This gateway traffics where it needs to go

• Dest MAC
• Source MAC
• Packet
• CRC

• Takes Frame apart and retracts Packet
• Looks at destination of packet
• Looks to router table to find where needs to go
• Recreates frame and sends to destination

• Operate at Network Layer
• Have 2 Nics so IP addresses acn communicate to two Lans
• Operates at layer 3 OSI
• Don't care about IP Addresses
• Care about subnets
• Work with logical IP's
• Work with packets
• Don't forward broadcasts
• Use routing tables
• Point to point since delievers only one step at a time

• Work with MAC addressses
• Work with Frames
• Broadcast across LANS
• Use switch tables

• Dest IP
• Source IP
• Data
• CRC
• Stays in one piece the whole way through

• Has Network and interface as columns
• Subnet, Mask, default gateway, Hops, interface
• If it doesn't recognize subnet, default is 0.0.0.0,0.0.0.0, default gateway IP, Hops, Interface
• Only has those for Lan's and default gateway

Tables craeted by user

Computer has a Routing Interface Protocol that learns the difffernt IP's and send messages to create the table

• 1st layer that operates from one end to other end
• Called end to end because it doesn't exist on routers
• TCP and UDP

• Breaks packet into parts and gives sequence number and sends out 1 after anotherHas a Source Port, Dest Port, Sequence #, Acknowledged  chunk of packet
• It's jot is to ensure end to end delivery
• Waits for response and when doesn't get one, sends again

• Doesn't gaurentee delivery
• Audio is example and used because it needs it right away and after the time has passed, it's not needed anymore.

• Physical: transmit recieve, NIC, c able, Hub
• Link: MAC, Fram, NIC, Switch
• Network: IP, Packets, router
• Transport: UDP, TCP
• Session Layer
• Presentation Layer
• Application Layer: Http

• Allows maintance on multiple sessions 
• Keeps track of assigning session ID so multiple things can happen at once

• Takes original data and presents to network depending on encrypt and decrypt messages
• Cahnges data according to request and makes srue other end understands revision

• One end talks to application and other end talks to network
• Http, ftp, fsnp
• You do not directly work with it.
• Example is on a browser you click something and it goes to Http and sends through presentation layer and so on

• No device on network has any specific responsibility
• easy set up 
• no more than 10 devices
• no central place for info

• Servers have a purpose to serve
• dedicated hardware, server 
• More expensive
• need more knowledge

• Hardware and software
• File server means a hardware designed for serving files
• Lots of server on one server so file server is service being provided

• How things are connected and work with each other
• Physical: messages goes along from person to person
• Logical: How communication takes place

• Simplest and needs 1 cable
• If cable breaks nothing will work
• Terminators at end to absorb and not confuse signal

• Most popular now days
• Central point where everyone connects to 
• Central control produces huge number cable runs is disadvantage

• Connected in a circle with no termination
• Signal travels 1 direction around ring

• Every computer is connected to every other computer
• A lot of reliability
• Used for LAN
• A start with circle around it

• 1 speaks and they all hear
• Only 1 can speak at a time

Flow of traffic goes to one computer to the next in a ring and in order

Can speak specifically to only one station

• Passive: simply repeats what is coming in 
• Active: repeats and boots signal

• Coax
• Twisted Pairs
• Fiber optics

• Bandwidth rating
• Maximum segment length
• Max num segments per internetwork
• Max num devices per segment
• Max num devices per internetwork
• Interfearence suceptability
• Connection hardware
• Cable grade
• Bend radius
• Material cost
• Installation cost

• Uses digital signal
• Medium can carry only one signal

• Analog signal
• Multiple bands per medium
• Simplex transmission: 1 directional
• Duplex: bidirectional on single medium
• Midsplit: break up 1 cable ans send and receive on it
• Dual: has 2 cables and receive and sends on seperate

• Core carries signal
• Has mesh shielding protect from EM radiation
• Old had thin (10Base2) Thick (10Base5)
• 10 = Bandwidth mbps, base = baseband, 2= segment length

• bend radius 360
• easy instal
• cheapest
• suseptable to eavesdroping
• Middle for interfearence

• Bend radius 30
• hard to install
• More expensive 
• Interfearence lowest of all cables

• Used in LANS
• STP: shielded twisted pair for electronicall noisy environments
• UTP: Unshielded twisted wher 10BaseT = T means UTP

• SMall glass or plastic core
• In core, light hits and refracts instead of going out and makes 1 and 0

• uses LED's plastic core
• Longer distance higher bandwidth
• 0 suseptbility to EM, no interfearence and no evesdroping
• For shorter distanc

• Uses laser
• Uses glass and allows for signal to last long distance 
• Up to 100 KM

• LAN standard
• 802.3 IDDD is bases for standard

• Enbed clock in signal
• It waits on amount of time when listens which is bit synce

• Sends AAAAAAB tells this is tart of frame and means you start listening
• 7 A's is Preamble
• B is sof (start of frame)

• <= o5DC then 802.3
• > o5DC the V2

• Carrier sense multiple access collision detection
• Can'g guarantee access

List of all nodes competing with eachother and connected to a hug

• Operate at layer 2 or OSI
• Bridge table has prort and mack
• Only bridge 2 LANS
• Bridges and switches seperate collision domain

• Standard Authority IANA
• First bit Class A: 1.0 - 126.0 with 2^32
• Frist 2 bit Class B: 128.0 - 191.255 with 65000
• First 3 bit Class C: 192.0 - 223.255.255 with 254

• 127.0.0.1 loopback is localhost
• Test nic to send and recieve packets to itslef

• Class A - 10.o.o.o
• Class B - 172.16.0.0
• Class C - 192.168.0.0

• More bits allaocated with 128 bits
• 48 bits routing prefix, 16 subnet, 64 identifier
• Every 4 hex seperated by :

• www.uwrf.edu
• Transles to IP first

only exists to translate do,main name to IP address