Connecting to the Network

1. Connecting to the Network Networking for Home and Small Businesses – Chapter 3

2. What is a network? • The ability to connect people and equipment no matter where they are in the world. • telephone • computers • television • How does your body work as a network??

3. Networking and Its Benefits A CONVERGED NETWORK!!!

4. Networking and Its Benefits • SOHO Network • Small Office/Home Office • sharing of resources • Internet • Printer

5. Networking and Its Benefits Schools, Corporations Internet

6. Networking and Its Benefits • Define the components of an Information network • Hosts • PCs • send and receive information across the network • connected to a network device • Peripherals • not directly connected to the network, but connected to hosts • Network devices • hub, switch, router • Network media • used to connect hosts/devices

7. Networking and Its Benefits • Clients and servers • software installed determines the role of a client or a server • Server software • enables the server to provide information to other hosts • Client software • enables the client to request and display information from the server • Example: Internet Explorer

8. Networking and Its Benefits • Build computer peer-to-peer network and verify • The ability to act as both a client and server

9. Network Topologies • Physical topology • created to record where each host is on the network • shows how each host is connected (media, devices, etc)

10. Network Topologies • Logical topology • how the host uses the network • host names, addresses, groups, applications

11. Communication Protocols • Primary purpose of a network – to communicate • Elements of communication • Sender (source) • has a need to communicate • Receiver (destination) • receives message and interprets it • Channel • pathway for information to travel

12. Successful delivery of the message • Rules (protocols) must be followed: • Identification of the sender and/or receiver • Channel in which to communicate (face-to-face) • Mode of communication (written or spoken) • Language • Grammar • Speed or timing

13. Communication Protocols • Encoding vs. Decoding • Encoding • Humans • converting thoughts into language, symbols, or sounds • Computers • messages converted into bits by sending host • each bit encoded into sound, light, or electrical impulses • destination host then decodes the signal • Decoding • reverse of encoding

14. Communication Protocols • Message formatting and encapsulation • Message needs a specific format • Compare to parts of a letter • Identifier (recipient) • Salutation • Message • Closing • Identifier (sender) • Encapsulation • placing the letter into the envelope • De encapsulation • letter removed from the envelope

15. Communication Protocols • Messages have size restrictions depending on the channel used • If the message is broken into smaller pieces, it is easier to understand • If the message is too long or too short, will be considered undeliverable.

16. Communication Protocols • Timing • when to speak; how fast or how slow • how long to wait for a response • Access Method • determines when someone is able to send a message • can speak when no one else is talking, otherwise a COLLISON occurs • Flow Control • timing for negotiations • sender might transmit messages faster than the user can handle • Response Timeout • how long should you wait for a response and what action to take • Acknowledgment • may be required to ensure message was delivered

17. Communication Protocols • Message Patterns • Unicast – single destination • Multicast – same message to a group • Broadcast – all hosts need to receive the message

18. Communication Protocols PROTOCOLS = RULES TO FOLLOW

19. Communication Across a Local Ethernet Network • Computers must speak the same language in order to communicate!!

20. Standards in technology • Standards – rules by which equipment from different vendors operate • Benefits of standards: • Facilitate design • Simplify product development • Promote competition • Provide consistency • Facilitate training • More vendor choices for customers

21. Communication Across a Local Ethernet Network • IEEE (Institute of Electrical and Electronic Engineers) • maintains networking standards • 802.3 – Ethernet standard • A breakdown of terminology • 100 Base-T • 100 = Speed in Mbps • Base = Baseband transmission • T = Twisted Pair

22. Communication Across a Local Ethernet Network • Physical addressing • MAC address (Media Access Control) • Ethernet communication • each interface has a MAC address • each device may look at the data, but only the interface that matches the destination MAC will respond

23. The Ethernet Frame • Preamble – beginning of the timing • SFD (Start Frame Delimiter) – marks the end of the timing, but beginning of the frame • Destination MAC • Source MAC • Length/Type • Length – tells which protocol receives the data • Type – number of bytes of data • Encapsulation – packet of information • FCS (Frame Check Sequence) – checks for damaged frames

24. The Hierarchical Design Structure • Smaller, more manageable groups allow traffic to remain local on the networks • Divided into three layers • Access Layer • connection to the hosts • Distribution Layer • interconnects smaller networks • Core Layer • high speed connection between • distribution devices

25. Logical Addressing • MAC vs. IP • IP Address (Logical Address) • assigned based on where the host is located • assigned by the administrator • Parts of an IP address • Network – same for all hosts connected to the LAN • Host – unique to each host on the network

26. Access Layer Devices • Most basic level • Made up of: • host devices • first line of networking devices • hub, switch, workstations

27. Access Layer Device – A HUB • Accepts data signal from one port and sends it (regenerates) out all ports • multiport repeater • Collisions • results in message being garbled and unreadable • occur when two or more hosts send a message at the same time (undesirable in a network) • NOT VERY SMART • a hub will not recognize there is a collision and send it all ports

28. Hubs And Collision Domains • Collision domain – area where the collision has occurred. • More collision domains = better performance • How many collision domains exist in the graphic shown?

29. Access Layer Device – A SWITCH • SMARTER THAN A HUB • dedicated bandwidth out each port • no need to share with other ports (unlike a hub) • Can forward messages to a specific host by looking in its MAC table • If destination MAC is not in its MAC table, floods the network out all ports looking for a response • Only the host with the correct MAC address will respond

30. More Stuff on Switches • How does the MAC table get built? • keeps track of frames being sent between hosts • records the information when there is a response • Collision Domains • each port on a switch is its own collision domain • 8 port switch = 8 collision domains • Online Activity 3.4.3

31. Broadcasts • If there is only one destination MAC in a message, how can you contact everyone else? • send a broadcast MAC • hexidecimal digits • FFFF.FFFF.FFFF • Useful when hosts need to send information but don’t know what hosts are to receive it • Switches and hubs send the broadcast out to everyone on their network. (Broadcast Domain) ONLINE ACTIVITY 3.4.5

32. ARP Request • Sent when the sending host knows the destination IP, but not the MAC • Will discover the MAC address of any local host on the network

33. Distribution Layer Devices and Communication Methods • Responsible for making sure local traffic stays local on the network • Traffic destined for other networks will be passed on.

34. Distribution Layer Devices—The Router • Routers – directs traffic based on the destination IP address • Routers build routing tables; switches build MAC tables • Routers decode packets, switches decode frames • Look only the network portion of the IP address • finds the best path to take to get to the destination • Routers do not forward broadcasts!!!

35. Default Gateway • Used when a host wants to send data to a host on a different network. • Must be set on the workstation connected to the routing device – the router interface connected to the PC Activity 3.5.3

36. Routing Tables and ARP tables • Used by routers to store information

37. Types of Routing • Dynamic • information is obtained from neighboring routers • Static • manually entered by the network administrator • What happen to a message that is not in the routing table? • It is dropped unless . . . • A default route is set • “last resort” type of router • will send it to the router it thinks may be have the destination IP • ONLINE ACTIVITY 3.5.4

38. Distribution Layer Devices and Communication Methods • LAN – Local Area Network • Under the same administrative control

39. Distribution Layer Devices and Communication Methods • Packet Tracer

40. Plan, Implement and Verify a Local Network • Consider the following before beginning: • Number and type of hosts • Applications to be run on the network • Data and devices to be shared • Speed requirements (bandwidth) • Level of security • Reliability of the network • Connectivity requirements

41. Building the Network • Physical environment • temperature control • availability/placement of outlets • Physical configuration • location of devices • how are devices connected • location/length of cable runs • hardware configurations (hosts, servers) • Logical configuration • size of broadcast & collision domains • IP addressing scheme • Naming • Permissions • Sharing

42. Multifunction Devices • Integrated routers • Linksys wireless router • problem = single point of failure • Cisco Integrated Services Router (ISR) • performs services of three different devices • router • switch • wireless access point

43. Implement and Document the Network • Develop a prototype • tests network design • PACKET TRACER – ACTIVITY 3.6.2

44. Sharing Resources • Main reason for networking – sharing resources • File sharing • Print sharing • Consider this before sharing: • security issues • permissions granted • Windows XP users • use Simple File Sharing