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Fundamentals of Networking. Discovery 1, Chapter 3 Connecting to the Network. Objectives. Explain the concept of networking and the benefits of networks. Explain the concept of communication protocols. Explain how communication occurs across a local Ethernet network.
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Fundamentals of Networking Discovery 1, Chapter 3 Connecting to the Network
Objectives • Explain the concept of networking and the benefits of networks. • Explain the concept of communication protocols. • Explain how communication occurs across a local Ethernet network. • Describe Access Layer devices and communication methods on a local Ethernet network. • Describe Distribution Layer devices and communication methods across networks.
What’s a Network? • Make a phone call, watching TV, radio, Internet, Gaming • All depend on a reliable network • Group of connected devices able to communicate with each other
Communication Now • OLD: • Separate, dedicated networks for voice, data, vide • NOW: • Converged into one over a single channel • Can you name examples?
Basic Network Components • 4 categories of components • Hosts • Shared peripherals • Networking devices • Networking media
Hosts • They send & receive data • Have an IP Address
Shared Peripherals • Shared devices ARE connected to a host • Rely on their connected hosts to share • Software allows the sharing • Print sharing with a USB connected printer
Networking devices • Connect hosts & other devices • Hubs, switches, routers • Move & control network traffic
Networking media • Connects Devices • Can be wired or wireless
Handout • Complete Handout 1
Computer Roles in a Network • Host sends & receives data on a network • Computer is a host • Can act as a client and/or a server • Server • Provide info to other hosts on a network • Simultaneously • Email, web pages, file access • Separate server software for each • Client • Requests & displays info from the server • Can check email & view web at same time • Web browser/IE, Outlook
Client-Server • Hosts have an IP Address • Hosts can act as a client or server • Depends on software installed • Server provides services to other hosts • Like providing email or web services • Clients request & display info from servers
Popular Client-Server Network • World of Warcraft • Players from all over the world connect & play
Peer-to-Peer Networks • One computer can sometimes act as the server & the client • Simplest: 2 connected devices • Uses a crossover cable or wireless • Multiple PC’s connect with a hub • Disadvantage • Host can slow down if doing both • Not for large networks • Dedicated servers to handle requests
Famous Peer-to-Peer • LimeWire • Exchanging MP3’s with another user • Only connected with that ONE user
Lab 3.1.5 • Building a Peer-to-Peer Network
Physical Topology • Layout/Map of network • Shows where each host is located, wiring, network devices
Logical Topology • Groups hosts by how they use the network • Not physical location • Host names, addresses, group info & applications can be recorded
Review • What does SOHO stand for? • Small office home office • What interconnects hosts & controls traffic? • Network devices • Which cable connects 2 PC’s together? • Crossover cable • Hosts are devices that have what? • IP Addresses • Describe client-server.
Principles of Communication • The Message • Source or Sender • Destination or Receiver • Channel or Pathway • Protocol or Rules
Rules of Human Communication • What are some of our rules of communication? • What if there were no rules?
Protocols • Rules of Communication over a medium • May be different depending on the medium • Protocols define the details of how the message is transmitted and delivered • This includes issues of:
Message Encoding • Encoding • Converting thoughts into words • Bits are encoded for that medium • Light, electricity, or radio waves • Destination will decode the message
Encapsulation of Data • Computer messages packed in a FRAME • Acts like an envelope • Provides the addresses • Must be properly addresses or won’t be delivered
Handout • Complete Handout 2 & 3 • Message Format Ordering
Review • What 4 things do you need for communication? • Source, destination, channel, protocol • Describe encoding. • Bits into electricity, light, or radio waves • A message is encapsulated in what? • Frame • Which 2 address are in the frame? • Source & destination MAC address
Message Size • You talk in sentences. • Length will vary depending on what can be processed or understood by the listener • Messages sent across networks are broken into smaller pieces • Size of a frame
Message Timing • People use timing to determine when to speak, how fast or slow to talk, and how long to wait for a response. These are the rules of engagement. • Access Method • Flow Control • Response Timeout
Message Timing • Access Method • When to begin sending & how to respond to errors • Collision if two talk at same time • Flow Control • Sender can transmit messages faster than the destination can receive & process • Use flow control to negotiate correct timing for successful communication • Response Timeout • How long to wait for responses & what to do
Unicast Message Pattern • Unicast • 1 to 1 single message
Multicast Message Pattern • Multicast • 1 to a group message
Broadcast Message Pattern • Broadcast • 1 to all
Review • What is it called when one message format is placed in another message format? • Encapsulation • Bob is talking to Sally. Which type of message pattern is this? • Unicast • Which address is used in a frame? • MAC address (source & destination)
Review • Which message is one to all? • Broadcast
Importance of Protocols • Computers need rules to communicate • Local network devices MUST speak same language • Most common wired protocol is ETHERNET
Early Days of Computing • Each vendor had their own rules • Standards had to be created
Standardizing • IEEE maintains standards approvals • Assigned a # • 802.3 is Ethernet • 100Base-T • 100 megabit Ethernet • Baseband Transmission • Twisted Pair Cabling
Physical Addressing • Remember encapsulating frames? • Source & destination address needed • Each host on Ethernet has a physical address (MAC Address) • Burned into NIC • NIC encapsulates source & dest. MAC • Host that receives frame reads dest. MAC • If it contains its own MAC, it will process it • If not, it ignores it
Lab 3.3.3 • Determine the Mac Address • Ipconfig /all
Ethernet Frame Structure • Frames are also called PDU’s • Protocol Data Units • 64-1518 bytes each frame • Preamble for timing • SFD is end of timing, begin frame • FCS- helps check for damaged frames