Networking Devices

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  • Brouters is a term
  • Networking Devices

    1. 1. CCNA Guide to Cisco Networking <ul><li>Chapter 2: Network Devices </li></ul>
    2. 2. Objectives <ul><li>Explain the uses, advantages, and disadvantages of repeaters </li></ul><ul><li>Explain the uses, advantages, and disadvantages of hubs </li></ul><ul><li>Define wireless access points </li></ul><ul><li>Define network segmentation </li></ul><ul><li>Explain network segmentation using bridges </li></ul>
    3. 3. Objectives (continued) <ul><li>Explain network segmentation using switches </li></ul><ul><li>Explain network segmentation using routers </li></ul><ul><li>Explain network segmentation using brouters and gateways </li></ul>
    4. 4. Repeaters <ul><li>Length of cable used influence the quality of communication </li></ul><ul><li>Attenuation </li></ul><ul><li>Repeaters repeat signals </li></ul><ul><ul><li>Clean and boost digital transmission </li></ul></ul><ul><ul><li>Analog networks use amplifiers to boost signal </li></ul></ul><ul><li>Repeaters only work with the physical signal </li></ul><ul><ul><li>Cannot reformat, resize, or manipulate the data </li></ul></ul><ul><li>Physical layer (layer 1) device </li></ul>
    5. 5. Repeaters (continued)
    6. 6. Repeaters (continued)
    7. 7. Hubs <ul><li>Generic connection device </li></ul><ul><ul><li>Physical layer </li></ul></ul><ul><li>Connect several networking cables together </li></ul><ul><li>Active hubs </li></ul><ul><ul><li>Multiport repeaters </li></ul></ul><ul><li>Passive hubs </li></ul><ul><li>Hubs and topology </li></ul>
    8. 8. Hubs (continued)
    9. 9. Advantages And Disadvantages Of Repeaters And Hubs <ul><li>Advantages of using repeaters </li></ul><ul><ul><li>Extend network physical distance </li></ul></ul><ul><ul><li>Do not seriously affect network performance </li></ul></ul><ul><ul><li>Special repeaters connect different media </li></ul></ul><ul><ul><ul><li>Copper to fiber </li></ul></ul></ul><ul><li>Disadvantages of using repeaters </li></ul><ul><ul><li>Cannot connect different network architectures </li></ul></ul><ul><ul><ul><li>Token Ring and Ethernet </li></ul></ul></ul><ul><ul><li>Cannot reduce network traffic </li></ul></ul>
    10. 10. Advantages And Disadvantages Of Repeaters And Hubs (continued) <ul><li>Disadvantages of using repeaters </li></ul><ul><li>Do not segment the network </li></ul><ul><ul><li>Repeat everything without discrimination </li></ul></ul><ul><ul><li>Number of repeaters must be limited </li></ul></ul><ul><li>Repeaters are part of a collision domain </li></ul>
    11. 11. Wireless Access Points <ul><li>Wireless local area networks (WLANs) </li></ul><ul><li>Wireless access points provide cell-based areas </li></ul><ul><ul><li>Contains radio transceiver </li></ul></ul><ul><ul><li>Function like a hub </li></ul></ul><ul><ul><li>Bandwidth is shared </li></ul></ul><ul><ul><li>May also function as a wireless repeater </li></ul></ul><ul><li>Wireless clients </li></ul>
    12. 12. Wireless Access Points (continued)
    13. 13. Network Segmentation <ul><li>Carrier Sense Multiple Access with Collision Detection (CSMA/CD) </li></ul><ul><li>Problems occur with too many nodes on the same network segment or collision domain </li></ul>
    14. 14. Network Segmentation (continued) <ul><li>Collision </li></ul><ul><ul><li>Back off algorithm </li></ul></ul><ul><ul><li>Back off period </li></ul></ul><ul><li>Segmentation </li></ul><ul><ul><li>Collisions and retransmissions are reduced </li></ul></ul><ul><ul><li>Contention for bandwidth is reduced </li></ul></ul>
    15. 15. Network Segmentation (continued)
    16. 16. Bridges <ul><li>Operate at the Data Link layer </li></ul><ul><li>Forward or drop frames </li></ul><ul><li>Cannot filter broadcasts </li></ul><ul><li>MAC to segment # table </li></ul><ul><li>MAC to segment # table initial development </li></ul>
    17. 17. Bridges (continued)
    18. 18. Transparent Bridges <ul><li>Also called learning bridges </li></ul><ul><li>Build a table of MAC addresses as frames arrive </li></ul><ul><li>Ethernet networks use transparent bridges </li></ul><ul><li>Token Ring networks use source-routing bridges </li></ul>
    19. 19. Source-Routing Bridges <ul><li>Used in Token Ring networks </li></ul><ul><li>Rely of source of the frame transmission </li></ul><ul><li>Explorer frames </li></ul>
    20. 20. Translation Bridges <ul><li>Connect networks with different network architecture </li></ul><ul><li>Example: </li></ul><ul><ul><li>Token ring connecting to Ethernet </li></ul></ul>
    21. 21. Advantages And Disadvantages Of Bridges <ul><li>Advantages of using a bridge </li></ul><ul><ul><li>Extend physical network </li></ul></ul><ul><ul><li>Reduce network traffic with minor segmentation </li></ul></ul><ul><ul><li>Creates separate collision domains </li></ul></ul><ul><ul><li>Reduce collisions </li></ul></ul><ul><ul><li>Connect different architecture </li></ul></ul>
    22. 22. Advantages And Disadvantages Of Bridges (continued) <ul><li>Disadvantages of using bridges </li></ul><ul><ul><li>Slower that repeaters due to filtering </li></ul></ul><ul><ul><li>Do not filter broadcasts </li></ul></ul><ul><ul><li>More expensive than repeaters </li></ul></ul>
    23. 23. Switches <ul><li>Operate at the Data Link layer </li></ul><ul><li>Increase network performance </li></ul><ul><li>Virtual circuits between source and destination </li></ul><ul><li>Micro segmentation </li></ul><ul><li>Multiple virtual circuits are called “switched bandwidth” </li></ul>
    24. 24. Switches (continued) <ul><li>Between two computers using a switch two collision domains are created each with dedicated bandwidth </li></ul><ul><li>Between two hubs using a switch two collision domains are created each with shared bandwidth </li></ul><ul><li>Filter based on MAC addresses </li></ul><ul><li>Build tables in memory </li></ul>
    25. 25. Switches (continued) <ul><li>Advantages of switches </li></ul><ul><ul><li>Increase available network bandwidth </li></ul></ul><ul><ul><li>Reduced workload, computers only receive packets intended for them specifically </li></ul></ul><ul><ul><li>Increase network performance </li></ul></ul><ul><ul><li>Smaller collision domains </li></ul></ul>
    26. 26. Switches (continued) <ul><li>Disadvantages of switches </li></ul><ul><ul><li>More expensive than hubs and bridges </li></ul></ul><ul><ul><li>Difficult to trace network connectivity problems through a switch </li></ul></ul><ul><ul><li>Does not filter broadcast traffic </li></ul></ul>
    27. 27. Switches (continued)
    28. 28. Routers <ul><li>Provide filtering and network traffic control </li></ul><ul><li>Used on LANs and WANs </li></ul><ul><li>Connect multiple segments and networks </li></ul><ul><li>Multiple routers create an “internetwork” </li></ul><ul><li>Operate at the Network layer </li></ul>
    29. 29. Routers (continued) <ul><li>Create a table to determine how to forward packets </li></ul><ul><li>Filtering and traffic control base on logical addresses </li></ul>
    30. 30. Physical Versus Logical Addresses <ul><li>MAC addresses </li></ul><ul><ul><li>Data Link layer application </li></ul></ul><ul><ul><li>Used by switches, bridges, and routers </li></ul></ul><ul><ul><li>Used for directly connected devices </li></ul></ul><ul><li>Logical addresses </li></ul><ul><ul><li>Network and transport protocols dictate the format of the logical network layer address </li></ul></ul><ul><ul><li>TCP/IP, IPX/SPX </li></ul></ul><ul><ul><li>IP addresses are assigned manually or by software </li></ul></ul>
    31. 31. Physical Versus Logical Addresses (continued)
    32. 32. Advantages And Disadvantages Of Routers <ul><li>Advantages of routers </li></ul><ul><ul><li>Can connect networks of different architecture </li></ul></ul><ul><ul><ul><li>Token Ring to Ethernet </li></ul></ul></ul><ul><ul><li>Choose best path through or to a network </li></ul></ul><ul><ul><li>Create smaller collision domains </li></ul></ul><ul><ul><li>Create smaller broadcast domains </li></ul></ul>
    33. 33. Advantages And Disadvantages Of Routers (continued) <ul><li>Disadvantages of routers </li></ul><ul><ul><li>Only work with routable protocols </li></ul></ul><ul><ul><li>More expensive than hubs, bridges, and switches </li></ul></ul><ul><ul><li>Routing table updates consume bandwidth </li></ul></ul><ul><ul><li>Increase latency due to a greater degree of packet filtering and/or analyzing </li></ul></ul>
    34. 34. Advantages And Disadvantages Of Routers (continued)
    35. 35. Brouters <ul><li>Hybrid device </li></ul><ul><li>Functions as a router for routable protocols </li></ul><ul><li>Functions as a bridge for non-routable protocols </li></ul><ul><li>Operates at Data Link and Network layers </li></ul>
    36. 36. Gateways <ul><li>A gateway is a combination of hardware and software </li></ul><ul><li>Translate between different protocol suites </li></ul><ul><li>Operates on all 7 layers of the OSI model </li></ul><ul><li>Most negative on network performance </li></ul><ul><ul><li>Latency </li></ul></ul>
    37. 37. Summary <ul><li>Network administrators use devices to control and extend the usable size of a network </li></ul><ul><li>These devices include repeaters, hubs, bridges, switches, routers, brouters, and gateways </li></ul><ul><li>Repeaters work against attenuation by cleaning and repeating signals that they receive on a network </li></ul><ul><li>Repeaters work at the Physical layer of the OSI model </li></ul><ul><li>They cannot connect different network architectures </li></ul>
    38. 38. Summary (continued) <ul><li>Repeaters do not reduce network traffic or segment the network </li></ul><ul><li>A hub ties several networking cables together to create a link between different stations on a network </li></ul><ul><li>An active hub has its own electrical power and acts as a repeater, whereas a passive hub provides no signal regeneration </li></ul><ul><li>Hubs operate at the Physical layer of the OSI model and do not segment the network </li></ul><ul><li>Network segmentation is the process of isolating hosts onto smaller segments to reduce the possibility of collisions </li></ul>
    39. 39. Summary (continued) <ul><li>Bridges and switches are two devices commonly used to segment networks </li></ul><ul><li>Bridges provide network segmentation by examining the MAC address that is sent in the data frame </li></ul><ul><li>Bridges can use transparent bridging or source-route bridging to determine which segment includes a specific physical address </li></ul><ul><li>Bridges operate at the Data Link layer of the OSI model </li></ul>
    40. 40. Summary (continued) <ul><li>Switches increase network performance by reducing the number of frames transmitted to the rest of a network </li></ul><ul><li>They do this by opening a virtual circuit between the source and the destination </li></ul><ul><li>Switches operate at the Data Link layer of the OSI model </li></ul>
    41. 41. Summary (continued) <ul><li>Routers operate at the Network layer of the OSI model and provide filtering and network-traffic control on LANs and WANs </li></ul><ul><li>They can connect multiple segments and networks </li></ul><ul><li>On a TCP/IP network, routers use IP addresses to route packets to the correct network segment </li></ul><ul><li>Routers use information from routing tables to move packets from one network to another </li></ul>
    42. 42. Summary (continued) <ul><li>A brouter is a hybrid device that functions both as a bridge for non-routable protocols and as a router for routable protocols </li></ul><ul><li>Brouters operate at both the Data Link and Network layers </li></ul><ul><li>Gateways are usually a combination of hardware and software and are used to translate between different protocols </li></ul><ul><li>They usually operate at layer 4 and above in the OSI model </li></ul>

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