Extended Interior Gateway Routing Protocol EIGRP Extended Interior Gateway Routing Protocol

What is EIGRP A link state protocol Similar to OSPF in scalability (allegedly easier to configure) Follows IGRP, where it is faster and can scale Offers multi-protocol support andrew.smith@barnfield.ac.uk

What is EIGRP Hop count of 224 Uses (10000000/bandwidth)*256 as a metric [simplified] Each AS (Autonomous System) will manage separate routed networks on the same ‘wire’ andrew.smith@barnfield.ac.uk

What is EIGRP IGRP will distribute to EIGRP and Vice Versa Router IGRP 123 Network 10.0.0.0 Router EIGRP 123 Network 172.16.0.0 andrew.smith@barnfield.ac.uk

EIGRP Concepts EIGRP maintains three tables: Neighbour table Topology table Routing table Uses Hellos to check router status Uses a short hold down timer to check router status Neighbour discovery and recovery Reliable Transport Protocol DUAL finite-state machine algorithm Measures distances (FD/RD) Has protocol dependant modules (PDMS = extendible) andrew.smith@barnfield.ac.uk

EIGRP maintains three tables Neighbour table Contains list of connected routers Topology table Keeps a map of the N/W based on: connected routers, costs, feasible distances, reported distances, successors feasible successors Routing table Contains results of the above tables andrew.smith@barnfield.ac.uk

EIGRP Neighbour packets 5 EIGRP packet types are: Hello Acknowledgment Update Query Reply EIGRP routers send hellos to the multicast IP address 224.0.0.10. All data transport is done by RTP which means that we are not dependant on a system protocol which may fail andrew.smith@barnfield.ac.uk

EIGRP Neighbour packets Image copyright Cisco Academy Programme andrew.smith@barnfield.ac.uk

The topology table is the clever bit Uses DUAL finite state machine Looks at the results of the packet types and exchanges between routers Lowest cost route is feasible distance Reported distance can be Equal the feasible distance thus be the successor, be lower than the FD (time for a DUAL change), Or higher which means that we have a feasible successor andrew.smith@barnfield.ac.uk

Image copyright Cisco Academy Programme So how does DUAL do IT! Image copyright Cisco Academy Programme andrew.smith@barnfield.ac.uk

Configuring EIGRP Router EIGRP 123 Network 172.16.0.0 No auto-summary EIGRP automatically summarises keeping routing tables compact, this may not be desired, thus andrew.smith@barnfield.ac.uk

Configuring EIGRP Router EIGRP 123 Network 172.16.0.0 No auto-summary EIGRP automatically summarises keeping routing tables compact, this may not be desired, thus andrew.smith@barnfield.ac.uk

Configuring EIGRP Router EIGRP 123 Network 172.16.0.0 No auto-summary EIGRP automatically summarises keeping routing tables compact, this may not be desired, thus andrew.smith@barnfield.ac.uk

Configuring EIGRP router(config-if)# ip summary-address eigrp autonomous-system-number ip-address mask administrative-distance Interface serial 0/0 ip summary-address eigrp 123 172.16.0.0 255.255.0.0 1 andrew.smith@barnfield.ac.uk

EIGRP Show commands Show ip eigrp neighbors Show ip eigrp topology Show ip eigrp interfaces andrew.smith@barnfield.ac.uk

NOW DO THE LABS in the curriculum andrew.smith@barnfield.ac.uk