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NT1210 Introduction to Networking

NT1210 Introduction to Networking. Unit 8: Chapter 8, The Internet Protocol (IP). 1. Objectives. Identify the major needs and stakeholders for computer networks and network applications. Identify the classifications of networks and how they are applied to various types of enterprises.

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NT1210 Introduction to Networking

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  1. NT1210 Introduction to Networking Unit 8: Chapter 8, The Internet Protocol (IP) 1

  2. Objectives • Identify the major needs and stakeholders for computer networks and network applications. • Identify the classifications of networks and how they are applied to various types of enterprises. • Compare and contrast the OSI and TCP/IP models and their applications to actual networks. • Explain the functionality and use of typical network protocols. 2

  3. Objectives • Differentiate among major types of LAN and WAN technologies and specifications and determine how each is used in a data network. • Explain basic security requirements for networks. • Use network tools to monitor protocols and traffic characteristics. • Plan and design an IP network by applying subnetting skills. • Explain the functionality of typical network protocols. 3

  4. Objectives • Plan and design an IP network by applying subnetting skills. • Categorize TCP/IP protocols according to network model layers. • Describe how TCP/IP addressing moves data packets through networks. 4

  5. Introducing the Internet Protocol (IP) • TCP/IP Model review: Layers 1 and 2 Protocols Example LAN/WAN Standards and Types in the TCP/IP Model Figure 8-1 5

  6. Introducing the Internet Protocol (IP) • TCP/IP Model review: Upper layers define non-physical (logical) networking functions Various Perspectives on the TCP/IP Model and Roles Figure 8-2 6

  7. Introducing the Internet Protocol (IP) • Network Layer protocols • IP: Most important protocol defined by Network layer • Almost every computing device on planet communicates, and most use IP to do so • Network layer also defines other protocols 7

  8. Introducing the Internet Protocol (IP) • Network Layer protocols: Part 1 Other TCP/IP Network Layer Protocols Table 8-1 8

  9. Introducing the Internet Protocol (IP) • Network Layer protocols: Part 2 Other TCP/IP Network Layer Protocols Table 8-1 9

  10. Introducing the Internet Protocol (IP) • IPv6: Next generation of IP addressing. • Needed because IPv4 addresses exhausted. • 128-bit long addresses: 2128 or 3.4x1038 or over 340 undecillion IPs, that’s 340 with 36 zero’s after it. • Customer usually gets /64 subnet, which yields 4 billion times IPs available in all of IPv4. • Comparison: Number of IPv4 addresses equal to weight of cat; number of IPv6 addresses equal to weight of Earth and provides enough IP addresses for every grain of sand on every beach on earth. 10

  11. Introducing the Internet Protocol (IP) • Migration to IPv6 has taken over decade and still in process. • IPv6 originally defined back in mid-1990s. • June 6, 2012 – Was the scheduled IPv6 Day, official worldwide “switch over” day, moved up to February 2012. IPv4 Vs. IPv6 Timeline Figure 8-3 11

  12. Introducing the Internet Protocol (IP) • IP defines many functions that work together with one ultimate goal: To send data from one host to another host through any TCP/IP network. • Most important functions include: • Creating end-to-end physical paths through TCP/IP network by interconnecting physical networks (LANs and WANs) using routers • Identifying individual hosts and groups of hosts using IP addressing • Routing (forwarding) IP packets to correct destination host Example of a Post Office Sorting a Letter Sent to Hollywood, California Figure 8-4 12

  13. Introducing the Internet Protocol (IP) • IP is like Post Office Example of a Post Office Sorting a Letter Sent to Hollywood, California Figure 8-4 13

  14. Introducing the Internet Protocol (IP) • Routers in IP network: Interconnect LANs and WANs via physical connectors called interfaces • Example: Cisco 1841 router with two built-in Gigabit Ethernet LAN interfaces that use RJ-45 connectors Enterprise Class Router, LAN Interfaces, and WAN Interfaces Figure 8-5 14

  15. Introducing the Internet Protocol (IP) • IP interconnects LANs and WANs Interconnected LANs and WANs: Redundancy, but No LAN/WAN Detail Figure 8-7 15

  16. Introducing the Internet Protocol (IP) • IPv4 Addresses • 32 bits • Expressed in binary and dotted decimal forms • Source and destination IP addresses included in 20-byte IP header added to all IP packets IPv4 Header Format and Fields Figure 8-8 16

  17. Introducing the Internet Protocol (IP) • Converting binary IP address to dotted decimal • Separate 32 bits into 4 groups of 8 bits each • Do binary-to-decimal conversion of each 8-bit number (each decimal value between 0 and 255) • Put period (dot) between each decimal number Generic View of Converting from Binary IP Address to DDN Format Figure 8-9 17

  18. Introducing the Internet Protocol (IP) • Example: Converting binary IP address to dotted decimal Converting Binary IP Address to DDN 10.1.2.3 Figure 8-10 18

  19. Introducing the Internet Protocol (IP): Routing • Routing IP Packets from Source to Destination • IP addressing groups addresses into networks • All addresses with same value in first parts of addresses considered to be in one network • Example: All addresses that begin with 11, 12, 13, 14, or 15 in that particular network Example IP Address Groupings: All with the Same First Octet in the Same Group Figure 8-11 19

  20. Introducing the Internet Protocol (IP): Routing • IP routing example with routing tables: PC11 in left LAN sends IP packet to address 12.1.1.21 (LAN on upper right) Example IP Address Groupings: All with the Same First Octet in the Same Group Figure 8-12 20

  21. Introducing the Internet Protocol (IP): Routing • Routers build routing tables in two ways • Staticconfiguration: Routes entered manually and do not change • Dynamicroutingprotocol: Application router uses to automatically learn new routes from other routers Routing Protocols Advertising All Addresses that Begin with 12 as One Route Figure 8-13 21

  22. Introducing the Internet Protocol (IP): Other Protocols • DomainNameSystem/Service (DNS): Mapping names to IP addresses • Users use names; IP routing uses numbers • DNS translates name into corresponding IP address • DNS client sends DNSRequest message • DNS server returns DNSReply DNS Name Resolution Request, Reply, and Packet to Server1 IP Address Figure 8-14 22

  23. Introducing the Internet Protocol (IP): Other Protocols Layer 3 - Network IP with its Support Protocols Figure 8-15 23

  24. IP Addressing on User LANs: Network Settings • Locations Need IP addresses • Each LAN and WAN interface on hosts and routers need IP address to communicate IP Addresses Used on Every LAN/WAN Interface Figure 8-17 24

  25. IP Addressing on User LANs: Network Settings • IP Address grouping: Allows IP routing to work better • Routers list one number to represent each network (address group) in routing tables IP Address Groupings: IP Networks Figure 8-18 25

  26. IP Addressing on User LANs: Network Settings • Original IPv4 RFC defined way to group IPv4 addresses using IPaddressclasses (classfulIPaddressing) • Every possible IPv4 address falls into class Summary of IPv4 Address Classes Based on First Octet Values Table 8-2 26

  27. IP Addressing on User LANs: Network Settings • Class A includes lower half of IPv4 address space: All IPv4 address that begin with first octet between 0 and 127 Example Class A Networks Table 8-3 27

  28. IP Addressing on User LANs: Network Settings • Class B includes ¼ of IPv4 address space with first octet value from 128 – 191 • Includes medium number (216) of medium sized IP networks for approximately 65,000 hosts per network Example Class B Networks Table 8-4 28

  29. IP Addressing on User LANs: Network Settings • Class C includes 1/8th of IPv4 address space with first octet between 192 and 223 • Large number of small IP networks: over 2,000,000 IP networks, each with 256 IP addresses each Example Class C Networks Table 8-5 29

  30. IP Addressing on User LANs: Network Settings • LAN IP address classes summary Summary of How Class Rules Break Down the IPv4 Address Space Figure 8-20 30

  31. IP Addressing on User LANs: Network Settings • Private addresses: Classful IP networks reserved for enterprises to use in their network designs • Can only be used on local LAN; can’t be routed through WAN (non-routable) • Not regulated by agencies such as ARIN or ICANN 31

  32. IP Addressing on User LANs: Network Settings • Static IP address assignment: Manually configured Static IP Address Assignment on Mac OS X Figure 8-21 32

  33. IP Addressing on User LANs: Network Settings • Most host OS’s allow static configuration of several network settings Host IP Settings Figure 8-22 33

  34. IP Addressing on User LANs: Network Settings • Dynamic Host Configuration Protocol (DHCP) defines way hosts can lease IP address from DHCP network server so does not have to be configured statically • Operates on client-server concept • DHCP protocol defined by set of RFCs Sample Network for DHCP Discussions Figure 8-23 34

  35. IP Addressing on User LANs: Network Settings • Example: IP address assignment design using both DHCP and statically assigned addresses Address Planning: Some Static, Some DHCP, for Every LAN Table 8-6 35

  36. IP Addressing on User LANs: Network Settings • Once DHCP server exists in network and has been configured with set of IP addresses to lease, DHCP clients can request IP addresses DHCP Lease Process between a DHCP Client and Server Figure 8-24 36

  37. IP Addressing on User LANs: Network Settings • User can see results of DHCP process from computer DHCP Client Configuration on Mac OS X Figure 8-25 37

  38. IP Addressing on User LANs: Network Settings • DHCP example: Crossing networks to access DHCP server Remote DHCP Client in Boston Figure 8-26 38

  39. Short Break Take 10 39

  40. IP Routing with Focus on Layer 3 • IP defines how to route packets across TCP/IP network • Some routing tasks must use logic from lower two layers because Network layer (3) cannot physically send bits • Network layer relies on Layers 1 and 2 logic for this IP Routing Perspective, While Ignoring LAN/WAN Details Figure 8-27 40

  41. IP Routing with Focus on Layer 3 • Router must have IP routingtable with useful entries to route IP packets. • Routing table may list multiple routes. • Each IP route identifies network, as well as other information about how to send packets to that network. • Routers look at incoming packet’s destination IP address and compare it to list of network IDs in its routing table to determine where to send packet to destination. 41

  42. IP Routing with Focus on Layer 3 • Finding a classful network ID based on IP address Five Classful Networks in a Small Corporate Network Figure 8-28 42

  43. IP Routing with Focus on Layer 3 • Each route in routing table lists: • Information about how to match IP packets • Forwarding instructions that tell router where to forward packets to (e.g., next router) • Example: R1’s IP routing table shows five network IDs so it knows routes to all five networks R1 Routing Table with Routes for Five Classful Networks Figure 8-29 43

  44. IP Routing with Focus on Layer 3 • Router compares incoming IP packet’s destination address to information in its routing tables to find best route to destination How Router R1 Uses its IP Routing Table: Match and Forward Figure 8-30 44

  45. IP Routing with Focus on Layer 3 Routing from End-to-End: Multiple Cooperative Routing Decisions Figure 8-31 45

  46. IP Routing with Focus on Layer 3: Subnetting • Classful IP networks and wasted IP addresses • Subnetting: Process of subdividing network to create smaller groups of consecutive IP addresses • Subnets (subdivided networks): Smaller groups of addresses Numbers of Classful Networks, and Their Sizes Figure 8-32 46

  47. IP Routing with Focus on Layer 3: Subnetting • Example: Several subnets created by subnetting network 10.0.0.0 • Each subnet has subnet/network ID Subdividing (Subnetting) Class A Network 10.0.0.0 Figure 8-33 47

  48. IP Routing with Focus on Layer 3: Subnetting • Example continued: IP addresses and networks replaced with five subnets of network 10.0.0.0 Sample Corporate Network Using Subnets of Network 10.0.0.0 Figure 8-34 48

  49. IP Routing with Focus on Layer 3: Subnetting • Subnetmask: Shows how much of IP address for each device is in common to all IPs in subnet • Example 255.255.255.0 (/24): First three octets (first 24 bits) must be equal for all subnets in network • PC11 sends packet to PC21 (destination IP address 10.1.2.21) • R1 will have route for PC21’s subnet (network ID 10.1.2.0) Routing Logic with Subnets and Masks Figure 8-35 49

  50. IP Routing with Focus on Layer 3: Subnetting • Classful networks have default subnet mask based on each class • Class A: 255.0.0.0 (8 bits) • Class B: 255.255.0.0 (16 bits) • Class C: 255.255.255.0 (24 bits) • If subnet mask anything other than default, then subnetting being used Routing Logic with Subnets and Masks Figure 8-35 50

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