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EIGRP Enhanced IGRP Chap 9, Semester 2

2012/7/5. 2. Overview. IntroductionEIGRP ConceptsDUALConfiguring EIGRP. 2012/7/5. 3. EIGRP. Enhanced Interior Gateway Routing Protocol (EIGRP) is a distance vector, classless routing protocol that was released in 1992 with IOS 9.21. As its name suggests, EIGRP is an enhancement of Cisco IGRP (In

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EIGRP Enhanced IGRP Chap 9, Semester 2

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    1. 2012/7/6 1 EIGRP Enhanced IGRP Chap 9, Semester 2

    2. 2012/7/6 2 Overview Introduction EIGRP Concepts DUAL Configuring EIGRP

    3. 2012/7/6 3 EIGRP Enhanced Interior Gateway Routing Protocol (EIGRP) is a distance vector, classless routing protocol that was released in 1992 with IOS 9.21. As its name suggests, EIGRP is an enhancement of Cisco IGRP (Interior Gateway Routing Protocol). Both are Cisco proprietary protocols and only operate on Cisco routers.

    4. 2012/7/6 4 EIGRP

    5. 2012/7/6 5 EIGRP – Hybrid Routing Protocol? The term hybrid routing protocol is sometimes used to define EIGRP However, this term is misleading because EIGRP is not a hybrid between distance vector and link-state routing protocols - it is solely a distance vector routing protocol. Therefore, Cisco is no longer using this term to refer to EIGRP

    6. 2012/7/6 6 Introduction

    7. 2012/7/6 7 EIGRP Introduction - 1 Cisco-proprietary routing protocol based on Interior Gateway Routing Protocol (IGRP) Classless (VLSM, etc) Faster convergence times, improved scalability, and superior handling of routing loops

    8. 2012/7/6 8 EIGRP Introduction - 2 EIGRP is an advanced routing protocol that relies on features commonly associated with link-state protocols. such as partial updates and neighbor discovery However, EIGRP is easier to configure than OSPF. EIGRP is an ideal choice for large, multi-protocol networks built primarily on Cisco routers.

    9. 2012/7/6 9 Features of EIGRP Reliable Transport Protocol (RTP) provides reliable and unreliable delivery of EIGRP packets Partial/Bounded Updates Diffusing Update ALgorithm (DUAL) guaranteeing loop-free paths and backup paths throughout the routing domain Establishing Adjacencies Building Neighbor and Topology Tables

    10. 2012/7/6 10 IGRP vs EIGRP

    11. 2012/7/6 11 IGRP vs EIGRP (Compatibility) IGRP and EIGRP are compatible with each other. Sharing of routes, is automatic between IGRP and EIGRP (with same AS #)

    12. 2012/7/6 12 IGRP vs EIGRP (Compatibility)

    13. 2012/7/6 13 IGRP vs EIGRP (Compatibility)

    14. 2012/7/6 14 IGRP vs EIGRP (Route tagging ) EIGRP will tag routes learned from IGRP or any outside source as external because they did not originate from EIGRP routers ??????? IGRP cannot differentiate between internal and external routes

    15. 2012/7/6 15 IGRP vs EIGRP (Hop count) IGRP has a maximum hop count of 255 EIGRP has a maximum hop count limit of 224

    16. 2012/7/6 16 IGRP vs EIGRP (metric calculation)

    17. 2012/7/6 17 IGRP ? EIGRP

    18. 2012/7/6 18 Bellman-Ford Algorithm

    19. 2012/7/6 19 DUAL? Later

    20. 2012/7/6 20 Protocol-Dependent Modules (PDM) EIGRP has the capability for routing several different protocols including IP, IPX, and AppleTalk using protocol-dependent modules (PDM). PDMs are responsible for the specific routing tasks for each Network layer protocol.

    21. 2012/7/6 21 Protocol-Dependent Modules (PDM)

    22. 2012/7/6 22 RTP & EIGRP Packets EIGRP was designed as a Network layer independent routing protocol therefore, it cannot use the services of UDP or TCP because IPX and Appletalk do not use protocols from the TCP/IP protocol suite.

    23. 2012/7/6 23 RTP & EIGRP Packets

    24. 2012/7/6 24 RTP Although "Reliable" is part of its name, RTP includes both reliable delivery and unreliable delivery of EIGRP packets, similar to TCP and UDP, respectively. Reliable RTP requires an acknowledgement to be returned by the receiver to the sender. An unreliable RTP packet does not require an acknowledgement. RTP can send packets either as a unicast or a multicast. Multicast EIGRP packets use the reserved multicast address of 224.0.0.10.

    25. 2012/7/6 25 EIGRP Partial/Bounded Updates

    26. 2012/7/6 26 Authentication EIGRP can be configured for authentication. RIPv2, EIGRP, OSPF, IS-IS, and BGP, too. It is good practice to authenticate transmitted routing information. ensures that routers will only accept routing information from other routers that have been configured with the same password or authentication information Note: Authentication does not encrypt the router's routing table.

    27. 2012/7/6 27 EIGRP Packet Types Hello Update Acknowledgement (ACK) Query Reply

    28. 2012/7/6 28 EIGRP Packet Types : Hello

    29. 2012/7/6 29 Hello Protocol : Default Interval & Hold Time

    30. 2012/7/6 30 Hold Time Hold time tells the router the maximum time the router should wait to receive the next Hello before declaring that neighbor as unreachable. By default, the hold time is three times the Hello interval

    31. 2012/7/6 31 EIGRP Packet Types : Update & ACK

    32. 2012/7/6 32 EIGRP Packet Types : Query & Reply

    33. 2012/7/6 33 DUAL : Introduction Diffusing Update Algorithm (DUAL) is the convergence algorithm used by EIGRP

    34. 2012/7/6 34 DUAL : Packets

    35. 2012/7/6 35 Administrative Distance (AD) AD is the trustworthiness (or preference) of the route source. EIGRP has a default administrative distance of 90 for internal routes and 170 for routes imported from an external source, such as default routes. When compared to other interior gateway protocols (IGPs), EIGRP is the most preferred by the Cisco IOS because it has the lowest administrative distance.

    36. 2012/7/6 36 Administrative Distance (AD)

    37. 2012/7/6 37 Autonomous System

    38. 2012/7/6 38 Who’s in charge of AS Number? The guidelines for the creation, selection, and registration of an autonomous system are described in RFC 1930. AS numbers are assigned by the Internet Assigned Numbers Authority (IANA), the same authority that assigns IP address space.

    39. 2012/7/6 39 Who Needs an AS Number? Usually ISPs (Internet Service Providers), Internet backbone providers, and large institutions connecting to other entities that also have an AS number. These ISPs and large institutions use the exterior gateway routing protocol Border Gateway Protocol, or BGP, to propagate routing information. BGP is the only routing protocol that uses an actual autonomous system number in its configuration.

    40. 2012/7/6 40 Who Needs an AS Number? The vast majority of companies and institutions with IP networks do NOT need an AS number because they come under the control of a larger entity such as an ISP.

    41. 2012/7/6 41 AS Number & Process ID Both EIGRP and OSPF use a process ID to represent an instance of their respective routing protocol running on the router. Router(config)# router eigrp autonomous-system Router(config)# router eigrp 1 In this example, the number 1 identifies this particular EIGRP process running on this router.

    42. 2012/7/6 42 AS Number & Process ID RIP does not use process IDs; therefore, it can only support a single instance of RIP Both EIGRP and OSPF can support multiple instances of each routing protocol, although this type of multiple routing protocol implementation is not usually needed or recommended.

    43. 2012/7/6 43 DUAL Concept

    44. 2012/7/6 44 DUAL Features

    45. 2012/7/6 45 Terms (Tables) Neighbor Table Topology Table Routing Table

    46. 2012/7/6 46 Terms (Operation) Successor Feasible Successor Feasible Distance (FD) Reported Distance (RD) or Advertised Distance (AD) Feasible Condition or Feasibility Condition (FC)

    47. 2012/7/6 47 Successor A neighboring router that is used for packet forwarding and is the least-cost route to the destination network.

    48. 2012/7/6 48 Successor Successor ??? (????????????????) ??? Routing Table & Topology Table

    49. 2012/7/6 49 Feasible Distance (FD) is the lowest calculated metric to reach the destination network. As with other routing protocols this is also known as the metric for the route.

    50. 2012/7/6 50 Feasible Distance Feasible distance ???????

    51. 2012/7/6 51 Feasible Successors One of the reasons DUAL can converge quickly after a change in the topology is because it can use backup paths to other routers known as feasible successors without having to re-compute DUAL A feasible successor (FS) is a neighbor who has a loop-free backup path to the same network as the successor by satisfying the feasibility condition.

    52. 2012/7/6 52 Feasible Successors Feasible successor ?????? (????????????????), ???? ??? Topology Table

    53. 2012/7/6 53 Feasibility Condition (FC) The feasibility condition (FC) is met when a neighbor's reported distance (RD) to a network is less than the local router's feasible distance to the same destination network. The reported distance or advertised distance is simply an EIGRP neighbor's feasible distance to the same destination network.

    54. 2012/7/6 54 Topology table or Topology database The successor, feasible distance, and any feasible successors with their reported distances are kept by a router in its EIGRP topology table or topology database. topology table can be viewed using the show ip eigrp topology command

    55. 2012/7/6 55 EIGRP ???? - again Hello Unreliable multicast packet Update Sent when topology changes Query Sent when router needs specific information from neighbors Reply Reply to query packet Acknowledgement Uni-cast Hello packet

    56. 2012/7/6 56 EIGRP Packet Header

    57. 2012/7/6 57 EIGRP Parameters TLV

    58. 2012/7/6 58 EIGRP Message Contents

    59. 2012/7/6 59 Active State – Sending Query Pkt If an EIGRP router loses its successor and cannot find a feasible successor for a route, DUAL places the route in the Active state A query is then multicasted to all neighbors to locate a successor to the destination network. Neighbors must send replies that either provide information on successors or indicate that no information is available Queries can be multicast or unicast, while replies are always unicast. Both packet types are sent reliably. Passive state is stable state

    60. 2012/7/6 60 EIGRP ??? Hello ? ????? routers ??? ???? ???? (???) ?? ???? (?? / ????)

    61. 2012/7/6 61 Hello - ????? routers ???

    62. 2012/7/6 62 Default Hello Interval for EIGRP

    63. 2012/7/6 63 Hello??? Neighbor & Topology Tables

    64. 2012/7/6 64 Neighbor Table Simple distance vector routers do not establish any relationship with their neighbors. They merely broadcast or multicast updates on configured interfaces. EIGRP routers actively establish relationships with their neighbors as do OSPF routers. The neighbor table is the most important table in EIGRP. Each EIGRP router maintains a neighbor table that lists adjacent routers. This table is comparable to the adjacency database used by OSPF. There is a neighbor table for each protocol that EIGRP supports

    65. 2012/7/6 65 DUAL ?? Neighbor & Topology Table ???? (???) ??

    66. 2012/7/6 66 ???? (???) ??? Routing & Topology Table

    67. 2012/7/6 67 ???? (???) ??

    68. 2012/7/6 68 Topology Table ???? (???) ??

    69. 2012/7/6 69 Legend (??????)

    70. 2012/7/6 70 Feasible Successor ? Topology Table ?????? feasible successors ????? feasible successor ????? RD ??? FD? ?? routing loop ??? Why?

    71. 2012/7/6 71 ???? – ?Topology???? …

    72. 2012/7/6 72 ????

    73. 2012/7/6 73 ????

    74. 2012/7/6 74 ????

    75. 2012/7/6 75 ????

    76. 2012/7/6 76 Dual Finite State Machine (FSM)

    77. 2012/7/6 77 Configuring EIGRP

    78. 2012/7/6 78 EIGRP Configuration : Topology

    79. 2012/7/6 79 EIGRP Configuration (router eigrp command) The router eigrp autonomous-system global configuration command enables EIGRP. The AS parameter is a number chosen by the network administrator between 1 and 65535. The number chosen is the process ID number and is important All routers in this EIGRP routing domain must use the same process ID number (autonomous-system number).

    80. 2012/7/6 80 EIGRP Configuration

    81. 2012/7/6 81 EIGRP wild card mask Router(config-router)#network network-address [wildcard-mask] A wildcard mask is the inverse of a subnet mask

    82. 2012/7/6 82 Verify EIGRP (show ip eigrp neighnors)

    83. 2012/7/6 83 Verify EIGRP (show ip eigrp neighnors) SRTT Smooth Round Trip Timer ???????, ??????????? RTO Retransmission Timer : Router ????????????, ??? Q Count Queue (# of packet in queue to be processed) Seq Num ???? neighbor ?????

    84. 2012/7/6 84 Verify EIGRP (show ip eigrp neighnors) If a neighbor is not listed after adjacencies have been established with a router's neighbors Check the local interface to make sure it is activated with the show ip interface brief command If the interface is active, try pinging the IP address of the neighbor If the ping fails, it means that the neighbor interface is down and needs to be activated

    85. 2012/7/6 85 Verify EIGRP (show ip eigrp neighnors) If the ping is successful and EIGRP still does not see the router as a neighbor, examine the following configurations: Are both routers configured with the same EIGRP process ID? Is the directly connected network included in the EIGRP network statements? Is the passive-interface command configured to prevent EIGRP Hello packets on the interface?

    86. 2012/7/6 86 Verify EIGRP (show ip protocol)

    87. 2012/7/6 87 Verify EIGRP (show ip route)

    88. 2012/7/6 88 Verify EIGRP (show ip route) By default, EIGRP automatically summarizes routes at the major network boundary Disable the automatic summarization with the no auto-summary command Notice that EIGRP routes are denoted in the routing table with a D, which stands for DUAL

    89. 2012/7/6 89 Null0 Summary Route

    90. 2012/7/6 90 Null0 Summary Route If a packet does not match one of the level 2 child routes, it is sent to the Null0 interface. Null0 is not an actual interface In other words, if the packet matches the level 1 parent - the classful network address - but none of the subnets, the packet is discarded

    91. 2012/7/6 91 Verify EIGRP (show ip route)

    92. 2012/7/6 92 EIGRP Composite Metric & K values

    93. 2012/7/6 93 Verifying the K Values

    94. 2012/7/6 94 Examining the Metric Values

    95. 2012/7/6 95 EIGRP Metric - Delay

    96. 2012/7/6 96 EIGRP Metric - Reliability Reliability (reliability) is a measure of the probability that the link will fail or how often the link has experienced errors. Unlike delay, Reliability is measured dynamically with a value between 0 and 255, with 1 being a minimally reliable link and 255 one hundred percent reliable. Reliability is calculated on a 5-minute weighted average to avoid the sudden impact of high (or low) error rates.

    97. 2012/7/6 97 EIGRP Metric - Load Load (load) reflects the amount of traffic utilizing the link. load is measured dynamically with a value between 0 and 255 Similar to reliability, load is expressed as a fraction of 255. 1/255 would be a minimally loaded link and 255/255 would be a link that is 100 percent saturated. Load is displayed as both an outbound (txload) and an inbound load value (rxload). This value is calculated on a 5-minute weighted average By default, EIGRP does not use load in its metric calculation.

    98. 2012/7/6 98 EIGRP Metric - Reliability

    99. 2012/7/6 99 Bandwidth Command

    100. 2012/7/6 100 Verify Bandwidth

    101. 2012/7/6 101 Calculating Default EIGRP Metric

    102. 2012/7/6 102 Metric Computation - Topology

    103. 2012/7/6 103 Metric Computation - Bandwidth

    104. 2012/7/6 104 Metric Computation - Bandwidth

    105. 2012/7/6 105 EIGRP Metric

    106. 2012/7/6 106

    107. 2012/7/6 107 debug eigrp fsm

    108. 2012/7/6 108 Null0 Summary Route A router’s routing table may contain routes that have an exit interface of Null0 ... Null0 interface is simply a route to nowhere So by default, EIGRP uses the Null0 interface to discard any packets that match the parent route but do not match any of the child routes.

    109. 2012/7/6 109 Null0 Summary Route Regardless of whether classful or classless routing behavior is being used, the null0 summary will be used and therefore denying the use of any supernet or default route.

    110. 2012/7/6 110 Null0 Summary Route Disabling automatic summarization will remove the Null0 summary route and allow EIGRP to look for a supernet or default route when an EIGRP child route does not match a destination packet.

    111. 2012/7/6 111 Manual Summarization

    112. 2012/7/6 112 EIGRP Default Route

    113. 2012/7/6 113 EIGRP Bandwidth Utilization

    114. 2012/7/6 114 Configuring Hello Intervals and Hold Times

    115. 2012/7/6 115 Homework Lab 9.6.1

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