CCNA Guide to Cisco Networking

1. CCNA Guide to Cisco Networking Chapter 4: Network Topology And Network Design

2. Objectives Discuss the different physical topologies Describe various network architecture models Determine which types of network media to use given a set of requirements Understand horizontal cabling standards and wiring closets Consider performance requirements and improvements for given situations

3. Objectives (continued) Install a telecommunications connector Wire a patch panel Test network cable Discuss LAN design Describe the function that network-management tools perform on a network

4. Physical Topologies Bus topology Bus topology advantages Inexpensive Easy to design Easy to implement Bus topology disadvantages Difficult to troubleshoot Requires termination

5. Physical Topologies (continued)

6. Physical Topologies (continued) Star topology Star topology advantages Break in one cable does not affect other devices (except up links) Easy to locate problems Easy to install Does not require termination like bus topology Star topology disadvantages Center of star topology device (hub) can be expensive Hub failure can affect entire topology Amount of cable is expensive

7. Physical Topologies (continued)

8. Physical Topologies (continued) Ring topology Ring topology advantages Prevents network collisions Each station acts like a repeater Ring topology disadvantages Cable break can affect all devices Temporarily shut down network to add a new station Maintenance and monitoring is difficult

9. Influence Of The 5-4-3 Rule On Topologies

10. Influence Of The 5-4-3 Rule On Topologies (continued)

11. Network Architecture IEEE 802 Logical Link Control (IEEE 802.2) CSMA/CD (802.3) Token Ring (802.5) Wireless Technologies (802.11) FDDI

12. Network Architecture (continued)

13. Media Twisted-Pair cabling have the following in common Copper based data transmission Copper wires come in pairs Each Wire of a pair is twisted around each other Copper wires are enclosed in a sheath All wire pairs are enclosed in a sheath

14. Media (continued) Unshielded twisted-pair (UTP) Advantages of UTP cable Thin and flexible Easy to install Many modern buildings come with CAT 5 installed Small size does not fill up wiring ducts fast Inexpensive per foot Disadvantages of UTP cable Susceptible to interference Cable length is 100 meters or 328 feet Register Jacks (RJ) RJ-45

15. Media (continued)

16. Media (continued) Shielded twisted-pair (STP) Advantages of STP cable Greater protection from interference Thin and flexible Overall it is easy to install Disadvantages of STP cable Inexpensive per foot but more than UTP STP must be grounded, problems exists if not grounded properly More difficult to install than UTP Small size but does fill up wiring ducts faster than UTP

17. Media (continued) Coaxial cabling (Thicknet and Thinnet) Advantages of coaxial cabling Cable lengths are longer than UTP/STP Less susceptible to interference than UTP Hubs are not required, direct connection Disadvantages of coaxial cabling Thicknet is very difficult to install More expensive than UTP Difficult to troubleshoot

18. Media (continued)

19. Media (continued)

20. Media (continued) Thinnet and Thicknet Connectors RG-58 cabling BNC Attachment unit interface (AUI) Barrel connectors T-connectors Terminators

21. Media (continued)

22. Media (continued) Fiber-Optic cable Advantages of fiber-optic cabling Transmit data over long distances Not susceptible to EMI High transmission rates Not susceptible to eavesdropping Small cable size Disadvantages of fiber-optic cabling Expensive Cable can be easily damaged during install making installations more difficult Manual termination of ends is time consuming

23. Media (continued)

24. Media (continued)

25. Media (continued)

26. Signal Degradation Three internal factors of attenuation Resistance Inductive reactance Capacitive reactance All three combined are called impedance External signal degradation Electromagnetic interference (EMI) Radio frequency interference (RFI)

27. Signal Degradation (continued) Reduce EMI/RFI Do not place copper media next to Fluorescent lights Generators/motors High-voltage electrical wire Proper installation Use quality cable Use shielded cabling Use repeaters to strengthen signal on long cable runs

28. Horizontal Cabling Standards Twisted-pair or fiber-optic connections between wiring closets Electronic Industries Alliance and Telecommunications Industry Association (EIA/TIA) EIA/TIA-568 UTP horizontal cable run max: 90 meters Horizontal cross connect max: 6 meters Workstation to horizontal drop max: 3 meters

29. Horizontal Cabling Standards (continued)

30. Wiring Closets Wiring closets EIA/TIA-568 and EIA/TIA-569 Catchment area Main distribution facility (MDF) Intermediate distribution facility (IDF)

31. Wiring Closets (continued) Proximity to the POP Backbone Sometimes called vertical cabling EIA/TIA-568 specifies four different cables for backbone installations 100-ohm UTP 150-ohm STP 62.5/125-micron optical fiber Single mode optical fiber

32. Wiring Closets (continued)

33. Wiring Closets (continued)

34. Performance Considerations Connection speeds Throughput Utilization Video or audio streaming/teleconferencing Client/server applications Host/terminal applications Routing protocols Routine maintenance tasks Broadcast traffic Ethernet collisions

35. Performance Considerations (continued) Solutions for reducing network utilization Segment network with switch, bridge, or router Reduce the number of services provided on the network Reduce the number of protocols on the network Control access to bandwidth intensive applications or protocols

36. Performance Considerations (continued) Calculating bandwidth and throughput Transmission Time = file size/bandwidth (T = Fs/Bw) Throughput = file size/download time (Tp = Fs/Dt) Collisions and contention Protocol analyzer Resource placement

37. Performance Considerations (continued)

38. Installing Telecommunications Connectors

39. Installing Telecommunications Connectors (continued)

40. Installing Telecommunications Connectors (continued)

41. Patch Panel

42. Patch Panel (continued)

43. Patch Panel (continued)

44. Testing Cable Cable testers Wire map Attenuation Noise Near end crosstalk (NEXT) Distance measure Baseline Error rates Collision rates Network utilization

45. Testing Cable (continued)

46. Testing Cable (continued)

47. Testing Cable (continued)

48. Testing Cable (continued)

49. LAN Design Models Two basic design strategies Mesh Hierarchical Three-layer network model Core Distribution Access layer Two-layer network model One-layer network model

50. LAN Design Models (continued)

51. LAN Design Models (continued)

52. LAN Design Models (continued)

53. Network Management Tools Common tools Cable testers Network monitors Network analyzers Network monitors and network analyzers have in common Agent Manager Administration system

54. Network Management Tools (continued) Simple Network Management Protocol (SNMP) Management information base (MIB) Management tasks include Network traffic monitoring Automatic disconnection of problem nodes Connection or disconnection of nodes based on time and/or date Port isolation for testing purposes Remote management capabilities Common management information protocol (CMIP)

55. Network Management Tools (continued)

56. Network Management Tools (continued)

57. Network Management Tools (continued)

58. Summary There are three basic physical LAN topologies: bus, star, and ring These topologies, or layouts, typically involve cable, such as UTP, STP, coaxial, or fiber The network architecture used on a LAN defines the physical topology, the media used, and the network access method The most popular architectures are 10BaseT, 100baseTx and Token Ring The IEEE has defined many standards that have influenced the way networks are designed and implemented

59. Summary (continued) It has also defined different network access methods, which include CSMA/CD, token-passing, and CSMA/CA One of the largest contributions from the IEEE is the 802 standard, which has subsets that define Ethernet (802.3),Token Ring (802.5), and wireless (802.11) network architectures The 802.2 standard from the IEEE subdivided the OSI Data Link layer into two parts to make functional distinctions between the Media Access Control (MAC) sublayer and the Logical Link Control (LLC) sublayer Ethernet is also known by its access method, CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

60. Summary (continued) Token Ring uses an entirely different access method that is governed by token passing The token, a small data frame, is passed from station to station around the ring, and a station can transmit only when it has the token FDDI uses token-passing like Token Ring networks, but it is not subject to the same limitations CSMA/CA is a network access method specified by the wireless LAN standard—802.11 This standard supports spread spectrum and infrared technologies for use on wireless LANs

61. Summary (continued) CSMA/CA nodes listen before sending but determine when to send based on a random backoff factor Before transmitting, CSMA/CA nodes send a notification that they are going to transmit Installing media on a network is a multifaceted project The layout of the network should be determined and documented The number of wiring closets necessary, as well as their locations, must be determined

62. Summary (continued) Standards for wiring closets, cable runs, distances, and cable must be considered when the routes are established Obstructions and EMI/RFI must be overcome After you install cable, you should test it for wiring, performance, and configuration problems Cable testers can be used to determine if cables are wired correctly, if they meet length standards, and if they have attenuation or noise problems When implementing a network, you can choose one of three hierarchical network models: one-layer, two-layer, or three-layer

63. Summary (continued) The one-layer network model is the least complex, and is a flat structure where all components function at essentially the same level The two-layer model separates the WAN from the rest of the internal network, which is usually done by adding routers with packet filters In the three-layer model, the internal LANs are further divided by backbone cabling, which has additional routers with packet filters In this model, the WAN connection is called the core layer, the backbone cabling and routers form the distribution layer, and the individual LANs function at the access layer

64. Summary (continued) Network administrators use network monitors and network analyzers to manage a network on a daily basis These tools can also be used to troubleshoot abnormal situations The main difference between a network monitor and network analyzer is the level of service provided The network analyzer typically offers more advanced features, such as SNMP querying, remote administration, and even automatic problem correction