Cisco CCNA module 10

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Cisco CCNA module 10

  1. 1. 1© 2004, Cisco Systems, Inc. All rights reserved. Module 10 Routing Fundamentals and Subnets
  2. 2. 222© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Objectives
  3. 3. 333© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id IP Address
  4. 4. 444© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id IP Address Grouping
  5. 5. 555© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routed and Routing Protocols • Consider that a packet needs to be sent from node A to node F. How would it decide which path to take?
  6. 6. 666© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Protocol vs Routed Protocol • A routed protocol 1. defines the end to end addressing and the packet format of a packet that is forwarded between nodes on different networks. Internet Protocol (IP) is a routed protocol • A routing protocol 1. exchanges topology information with adjacent routers to update and maintain their routing tables. 2. selects the best path through a network RIP is a routing protocol
  7. 7. 777© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routed Protocol • A protocol is a set of rules • A routed protocol is a set of rules that determines how computers at the source and destination communicate with each other across networks – packet format – end to end addressing • In order for a protocol to be routable, it must provide the ability to assign both a network number and a host number for each individual device.
  8. 8. 888© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Internet Protocol IP • IP is a connectionless, unreliable, best-effort delivery protocol • As information flows down the layers of the OSI model, the data is processed at each layer. • IP accepts whatever data is passed down to it from the upper layers.
  9. 9. 999© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id IP Packet Header
  10. 10. 101010© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Network Layer Devices in Data Flow • As a frame is received at a router interface. • The MAC address is checked to see if the frame is directly addressed to the router interface, or a broadcast. • The frame header and trailer are removed and the packet is passed up to Layer 3. • The destination IP address is compared to the routing table to find a match. • The packet (datagram) is placed in a new frame with the MAC address of the next hop interface. • The frame is then transmitted. If a match is found or there is a default route, the packet will be sent to the interface specified in the matched routing table statement otherwise packet is discarded
  11. 11. 111111© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Packets Travel Across Links in a Frame • Packets NEVER travel through the network – they are carried within frames • A new frame MUST be created to carry the packet over each individual link • Routers provide the IP address of the next hop interface (router or host) • The ARP table provides the MAC address of this IP address for the frame destination
  12. 12. 121212© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Connectionless vs. Connection-Oriented • In a connection oriented system is established between the sender and the recipient before any data is transferred. – example: Telephone • In a connectionless system, the destination is not contacted before a packet is sent. – example: Postal system • TCP is connection oriented • IP is connectionless
  13. 13. 131313© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Connectionless Network Services • The Internet is a huge network where packets are routed according to their IP addresses. • IP is unreliable and best-effort as IP does not verify that the data reached its destination and therefore does not resend missing packets. • Reliability and resending of packets is handled by the upper layer protocols. • IP may be used in conjunction with TCP to add a Layer 4, connection- oriented service that checks for missing segments and resends them to provide reliability.
  14. 14. 141414© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id The IPv4 Packet Header Time-to-live (TTL) Count Decreases with every hop This prevents packets from looping endlessly.
  15. 15. 151515© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing
  16. 16. 161616© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id The Network Layer
  17. 17. 171717© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing • Routing is an OSI Layer 3 function. • Routers connect networks (or subnetworks) • Routing is the process of finding the most efficient path from one device to another (router) • Routers must maintain routing tables and make sure other routers know of changes in the network topology. This function is performed using a routing protocol to communicate network information with other routers
  18. 18. 181818© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Through a Network • A router is a network layer device that uses one or more routing metrics to determine the optimal path through the network
  19. 19. 191919© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Metrics
  20. 20. 202020© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Data Encapsulation
  21. 21. 212121© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Layer 3 Routing and Layer 2 Switching
  22. 22. 222222© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routers Reduce the Size of Broadcast Domains • Routers block LAN broadcasts, so a broadcast storm only affects the broadcast domain from which it originated • Switched networks do not block broadcasts
  23. 23. 232323© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing and Switching in a Network
  24. 24. 242424© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id ARP Tables and Routing Tables
  25. 25. 252525© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id The difference between a routed and routing protocol – revisited
  26. 26. 262626© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routed Protocol
  27. 27. 272727© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Protocol
  28. 28. 282828© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routed Vs Routing protocols • A Routed Protocol: – A network protocol suite that provides enough information in its network layer address to allow a router to forward it to the next device and ultimately to its destination. – Defines the format and use of the fields within a packet. – The Internet Protocol (IP) and Novell's Internetwork Packet Exchange (IPX), DECnet, AppleTalk, Banyan VINES, and Xerox Network Systems (XNS) • A Routing Protocol: – Provides processes for sharing route information. Exchange topology info. To determining the best routing paths and transporting packets through an internetwork – Also allows routers to communicate with other routers to update and maintain the routing tables. – Routing Information Protocol (RIP), Interior Gateway Routing Protocol (IGRP), Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), and Enhanced IGRP (EIGRP).
  29. 29. 292929© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Back to Routing
  30. 30. 303030© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Path Determination
  31. 31. 313131© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Path Determination
  32. 32. 323232© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Tables • Routing tables contain the best routes to all known networks. • These routes can be either – Static routes, which are entered manually by the system administrator – Or dynamic routes, which are constructed from information passed between adjacent routers. • A routing table entry contains: – Each Destination – The next hop IP address to reach that destination – The metric for the route via that next hop – Outbound router interface for the next hop
  33. 33. 333333© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Tables
  34. 34. 343434© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Algorithms and Metrics • Routing protocols have one or more of the following design goals: Optimization Simplicity and low overhead Robustness and stability Flexibility Rapid convergence
  35. 35. 353535© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Routing Algorithms and Metrics
  36. 36. 363636© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Interior and Exterior Gateway Protocols
  37. 37. 373737© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Interior and Exterior Gateway Protocols • IGPs route data within an autonomous system. RIP, RIPv2, IGRP, EIGRP, OSPF, IS-IS • EGPs route data between autonomous systems Border Gateway Protocol (BGP)
  38. 38. 383838© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Interior Gateway Routing Protocols • Link State and Distance Vector Routing Protocols • Examples of distance-vector protocols: Routing Information Protocol (RIP) Interior Gateway Routing Protocol (IGRP) Enhanced IGRP (EIGRP) • Examples of link-state protocols: Open Shortest Path First (OSPF) Intermediate System-to-Intermediate System (IS-IS)
  39. 39. 393939© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Mechanics of Subnetting
  40. 40. 404040© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting • Reasons for subnetting – Provides addressing flexibility for the network administrator. • Each LAN must have its own network or subnetwork address. – Provides broadcast containment and low-level security on the LAN. – Provides some security since access to other subnets is only available through the services of a router.
  41. 41. 414141© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id IP Address Bit Patterns
  42. 42. 424242© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Introduction to Subnetting • Host bits must are reassigned (or “borrowed”) as network bits. • The starting point is always the leftmost host bit. 3 bits borrowed allows 23 -2 or 6 subnets 5 bits borrowed allows 25 -2 or 30 subnets 12 bits borrowed allows 212 -2 or 4094 subnets
  43. 43. 434343© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting Chart (Bit Position and Value)
  44. 44. 444444© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting Chart (Subnet Mask Identifier)
  45. 45. 454545© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting
  46. 46. 464646© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting Chart
  47. 47. 474747© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnetting Example • This is an example of subnetting the 192.168.10.0 class C network into 8 subnets with 32 host addresses per subnet • Note that the first and last subnets are not used (the first can be) • Also the first and last host address in each subnet are not used
  48. 48. 484848© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Example Host IP Address from Subnet 2 Packet Address 192.168.10.65 11000000.10101000.00001010.010 00001 Subnet Mask 255.255.255.224 11111111.11111111.11111111.111 00000 Subnet Address 192.168.10.64 11000000.10101000.00001010.010 00000 • The subnet mask is ANDed with the packet address to determine the subnet address - as shown in the next slides
  49. 49. 494949© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id The Logical ANDing Process
  50. 50. 505050© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Calculating the Subnet ID
  51. 51. 515151© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Subnet Mask Defines the Number of Subnets
  52. 52. 525252© 2004, Cisco Systems, Inc. All rights reserved. www.pnj.ac.id Summary

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