1. Bellevue University CIS 341A Mid-Term Review

2. The exam Monday, June 30, at 6 PM 35 Question multiple choice, True/False, and fill in the blanks You have 70 minutes to complete the exam The exam will be closed book, closed notes, closed communication between students

3. Scoring 2.8 points for each correct answer 2 points for putting your name on your paper and turning it in If the entire class gets a question wrong, it will be thrown out and 2.8 points will be credited to each student

4. What to study The review slides The Reading Assignments The Lab Assignments The Quizzes

5. What the exam will cover Internetworking Internet Protocols IP Subnetting and Variable Length Subnet Masks (VLSMs) Introduction to the Cisco IOS IP Routing

6. Internetworking Basics A network consists of two or more hosts connected by a common communications medium for the purpose of sharing information. An internetwork consists of two or more networks connected by routers.

7. Internetworking Basics In Ethernet twisted pair networks, switches are typically used to connect hosts together. In internetworks routers are used to connect networks together.

8. Switches and Routers Layer 2 switches break up collision domains Layer 3 switches and routers break up broadcast domains

9. The OSI Model 7 layer abstract network model Simplifies design and interaction of protocols Provides a framework for the study of protocols

10. The OSI Reference Model OSI Reference Model’s Seven Layers –Application Layer –Presentation Layer –Session Layer –Transport Layer –Network Layer –Data Link Layer –Physical Layer

11. The OSI Reference Model Application Layer: File, print, message, database and application services. Presentation Layer: Data encryption, compression and translation services. Session Layer: Dialog control. OSI Reference Model’s Seven Layers and Functions Transport Layer: End-to-end connection. Network Layer: Routing. Data Link Layer: Framing. Physical Layer: Physical topology.

12. The OSI Reference Model The Transport Layer The address used in the transport layer is the port number There are two protocols that operate at this layer: Transmission Control Protocol and User Datagram Protocol Each protocol has its own set of 65536 ports

13. The OSI Reference Model The address used in the Network layer is the IP Address A protocol number is also used to determine what protocol to deliver the packet to at the destination. The Network Layer

14. The OSI Reference Model The Data Link Layer The address used in the data link layer is the physical address (also known as hardware or MAC address.

15. The OSI Reference Model The Physical Layer Sends and receives bits; 1’s & 0’s Specify electrical, mechanical, procedural, and functional requirements DTE/DCE interfaces identified Hubs (Multi-port repeaters)

16. Ethernet Networking A connection media access method that allows all hosts on a network to share the same bandwidth (Uses Data Link & Physical Layer specifications) CSMA/CD Half Duplex Full Duplex

17. Ethernet at the Data Link Layer Ethernet addressing = Hardware or MAC Framing –Types of Ethernet frames: Ethernet II IEEE 802.3 IEEE 802.2 SNAP Ethernet Networking

18. Ethernet Frames

19. Ethernet Cabling Unshielded twisted pair Coax Fiber

20. Connecting devices together Use these guidelines when cabling between ports: 1.Use straight through cables when connecting unlike devices together 2.Use crossover cables when connecting like devices together

21. Wireless Networking

22. Wireless Network Types Narrowband Wireless LANs Personal Communication Services (PCS) Narrowband PCS Broadband PCS Satellite Infrared Wireless LANs Spread Spectrum Wireless LANs

23. Data Encapsulation

24. TCP/IP and the DoD Model

25. The TCP/IP Protocol Suite TCP/IP and the DoD Model

26. Host-to-Host Layer Protocols TCP/IP and the DoD Model Transmission Control Protocol (TCP)

27. Host-to-Host Layer Protocols TCP/IP and the DoD Model User Datagram Protocol (UDP)

28. Key Concepts of Host-to-Host Protocols TCP/IP and the DoD Model

29. Port Numbers < 1024: “Well-known port numbers” –Defined in RFC 3232; linked to specific applications or protocols 1024: Dynamically assigned –Used by upper layers to communicate between hosts TCP/IP and the DoD Model

30. Internet Layer Protocols Internet Protocol (IP) Internet Control Message Protocol (ICMP) Address Resolution Protocol (ARP) Reverse Address Resolution Protocol (RARP) TCP/IP and the DoD Model

31. Internet Layer Protocols TCP/IP and the DoD Model

32. Internet Layer Protocols TCP/IP and the DoD Model

33. Internet Layer Protocols TCP/IP and the DoD Model

34. Local ARP Broadcast TCP/IP and the DoD Model

35. RARP Broadcast TCP/IP and the DoD Model

36. Binary to Decimal and Hexadecimal Conversion

40. IP Addressing The Hierarchical IP Addressing Scheme Dotted-decimal, as in 172.163.30.56 Binary, as in 10101100.00010000.00011110.0011100 0 Hexadecimal, as in AC.10.1E.38

41. Summary of the Three Classes of Networks IP Addressing

42. Reserved IP Addresses IP Addressing

43. Classful Routing The class of an IP address is determined by its most significant bits. 0 Class A 10 Class B 110 Class C 1110 Class D 1111 Class E

44. IP Addresses Class A – 0.0.0.0 through 127.255.255.255 Class B – 128.0.0.0 through 191.255.255.255 Class C – 192.0.0.0 through 123.255.255.255 Class D – 124.0.0.0 through 239.255.255.255 Class E – 240.0.0.0 through 255.255.255.255

45. Classful Routing Only Class A, B, and C addresses are routable through the Internet.

46. Class A Addresses Structure –Network –Network.node.node.node Class A Valid Host IDs –10.0.0.0All host bits off –10.255.255.255All host bits on –Valid hosts = 10.0.0.1 - 10.255.255.254 0’s & 255s are valid hosts but hosts bits cannot all be off or on at the same time! 2 24 -2 = 2 22 IP Addressing

47. Class B Addresses Structure –NetworkNetwork –Network.Network.node.node Class B Valid Host IDs –172.16.0.0All host bits off –172.16.255.255All host bits on –Valid hosts = 172.16.0.1 - 172.16.255.254 0’s & 255s are valid hosts but hosts bits cannot all be off or on at the same time! 2 16 -2 = 2 14 IP Addressing

48. Class C Addresses Structure –NetworkNetworkNetwork –Network.Network.Network.node Class C Valid Host IDs –192.168.100.0All host bits off –192.168.100.255All host bits on –Valid hosts = 192.168.100.1 - 192.168.100.254 0’s & 255s are valid hosts but hosts bits cannot all be off or on at the same time! 2 8 -2 = 2 6 IP Addressing

49. Private IP Addresses IP Addressing

50. Broadcast Addresses

51. Subnetting Basics Benefits of subnetting include: –Reduced network traffic –Optimized network performance –Simplified management –Facilitated spanning of large geographical distances.

52. Subnet Mask A 32-bit binary number that determines what part of an IP address is the network part and what part is the host part.

53. Default Subnet Masks

54. Classless Inter-Domain Routing (CIDR) Used to allocate an amount of IP address space to a given entity (company, home, customer, etc). Example: 192.168.10.32/28 The slash notation (/) means how many bits are turned on (1s) and tells you what your subnet mask is.

55. CIDR Values

56. Subnetting Class C Addresses

57. Subnetting Class C Addresses – Binary Method

58. Subnetting Class C Address – Binary Method (cont.)

59. How Many Subnets? 2 x -2 = number of subnets. –X is the number of masked bits, or the 1s. –For example, in 11000000, the number of ones gives us 2 2 -2 subnets. In this example there are 2 subnets.

60. How Many Hosts Per Subnet? 2 y -2 = number of hosts per subnet. –Y is the number of unmasked bits, or the 0s. –For example, in 11000000, the number of zeros gives us 2 6 -2 hosts. In this example, there are 62 hosts per subnet.

61. What Are The Valid Subnets? 256-subnet mask = block size, or base number. For example 256-192=64. 64 is the first subnet. The next subnet would be the base number plus itself or 64+64=128, (the second subnet).

62. What’s The Broadcast Address For Each Subnet? The broadcast address is all host bits turned on, which is the number immediately preceding the next subnet.

63. What Are The Valid Hosts? Valid hosts are the number between the subnets, omitting all 0s and all 1s.

64. Subnets with no VLSM applied

65. Subnets with VLSM applied

66. Implementing VLSM Networks

67. Four Immutable Laws The lowest numbered address in a range of IP addresses that constitute a subnet is the network address. This address cannot be assigned to a host. The highest numbered address in a range of IP addresses that constitute a subnet is the broadcast address. This address cannot be assigned to a host. For any IP address in a range of IP addresses that constitute a subnet, the network part of the IP address must be identical. For any IP address in a range of IP addresses that constitute a subnet, the host part of the IP address must be unique.

68. Cisco Router IOS Carries network protocols and functions Connects high-speed traffic between devices Adds security to control access Provides scalability for growth Supplies reliability

69. Bringing up a Router Boot-up process: 1: POST 2: Looks for the Cisco IOS from Flash memory 3: IOS loads & looks for a valid configuration; startup-configstartup-config stored in nonvolatile RAM (NVRAM) 4: If a valid config is not found in NVRAM: setup modesetup mode

70. Setup Mode Basic Management Setup Extended Setup Command-Line Interface

71. Command-Line Interface (CLI) More flexible than setup mode. To use the CLI, just say No to entering the initial configuration dialog.

72. Logging into the Router User mode: –Router> –Used mostly to view statistics Privileged mode: –Router# –Used to view & change router configuration

73. Overview of Router Modes Global changes: –config terminal or config t running-config –Changes made to running-config (DRAM) startup-config –To change the startup-config (NVRAM) config memory or config mem running-config Note: Any configuration changes need to be placed into RAM. Typing config mem or config net (from a TFTP host) will replace the current running-config

74. Configuration CLI Prompts Interfaces Sub-interfaces Line Commands Routing Protocol Configurations

75. Editing & Help Features Commands starting with a certain letter Router#c? clear clock configure connect copy Enhanced Editing Commands Router-Command History Gathering Basic Routing Information –show version

76. Setting the Passwords 5 passwords: –1st two used to set your enable password Used to secure privileged mode; Router>enable user –Other three are used to configure a password in user mode via: console port auxiliary port Telnet

77. Passwords Enable passwords Router(config)#enable password cisco Router(config)#enable secret cisco Auxiliary Password Console Password Telnet Password Encrypting Your Password Router(config)#service password-encryption

78. Banners Purpose Types –exec –incoming –login –motd Delimiting character

79. Router Interfaces Purpose Bringing up an Interface no shutdown shutdown show interface Configuring an IP Address on an Interface Router(config)#int e0 Router(config-if)#ip address 172.16.10.2 255.255.255.0 Router(config-if)#no shut Serial Interface Commands clock rate & bandwidth (entered in kilobits)

80. Hostnames & Descriptions Hostnames Router(config)#hostname todd todd(config)# Descriptions Atlanta(config)#int e0 Atlanta(config-if)#description Sales Lan

81. Viewing, & Saving Configurations Viewing & Saving Configurations –running-config –running-config saved in DRAM –startup-config –startup-config saved in NVRAM copy run start sh run sh start erase startup-config

82. Verifying Your Configuration Tools: show running-config show startup-config ping show cdp nei detail trace telnet

83. Other Verification Methods Verifying with the show interface command –Router#show interface ? Verifying with the show ip interface command –Router#show ip interface –Router#show ip interface brief –Router#show controllers

84. Routing Definition –Routing protocol –Routed protocol What must routers know?

85. IP Routing in Our Network Routing tables Routing protocols Types of routing –Static –Default –Dynamic

86. Routing Table Converts the destination address in a packet header to the IP address of the next link. The address of the next link is converted to the hardware address of the next link by arp.

87. Routing Protocols A routing protocol is used to dynamically update a routing table. It uses information from other routers to add, modify, or delete routes in its own table.

88. IP Routing Process (cont.)

89. Static Routing Definition Benefits Disadvantages Adding a static route: ip route [destination_network] [mask] [next_hop_address or exitinterface] [administrative_distance] [permanent]

90. Default Routing Definition – Default routing is routing traffic based on the destination IP not matching any entries in the routing table. Configuration – A default route is configured as the last route in the table. Any destination IP that doesn’t match any entries in the table will use the default route.

91. Dynamic Routing Definition: Dynamic routing is a process by which routes are automatically added, modified, or deleted based on information received from other routers. Types of Routing Protocols –Routing Information Protocol (RIP) –Open Shortest Path First (OSPF) –Interior Gateway Protocol (IGP) –Enhanced Interior Gateway Protocol (EIGRP) –Exterior Gateway Protocol (EGP)

92. Classes of Routing Protocols Classes –Distance Vector –Link State –Hybrid

93. Stopping Routing Loops Maximum Hop Count – A route is removed from the routing table if its hop count exceeds a preset value (RIP – 15 hops, IGRP – 255 hops). Split Horizon – prevents the router from advertising a route that goes back to itself. Route Poisoning – a router advertises a route then marks it unreachable. Holddowns – Keeps a router from announcing a route change until a certain amount of time has elapsed.

94. Routing Information Protocol (RIP) A true distance-vector protocol –Sends updates every 30 seconds on all active interfaces –Only uses hop count Maximum allowable hop count of 15 Good for small networks –Inefficient on large networks or slow WAN links

95. RIP RIP Timers –Route update timer – how much time to wait between updates –Route timeout timer – how much time to wait before marking a route as invalid –Route flush timer – how much time to wait before flushing a route

96. Interior Gateway Routing Protocol (IGRP) Definition Cisco proprietary distance vector routing protocol that uses multiple metrics to determine dynamic routes. IGRP Timers –prevent “route flapping” –Update timers – specifies how frequently update messages should be sent –Invalid timers – how long a router should wait before declaring a route as invalid –Holddown timers - how much time to wait before sending an update message –Flush timers – how much time to wait before removing a route