© Synergon Informatika Rt., 1999 Chapter 8 Configuring IGRP

2 Objectives Upon completion of this chapter, you will be able to perform the following tasks: Describe IGRP features and operation Configure IGRP Verify IGRP operation

3 Introduction to IGRP Scalable to very large internetworks Fast response to network changes Sophisticated metric Multiple-path support IGRP

4 IGRP Operation  Flash updates Holddown timers Split horizon Poison reserve updates ABC Network 100 Flash Update Holddown Timer Split Horizon Poison Reserve

5 IGRP Operation (cont.)  Router A’s link to network 100 fails ABC Network 100 Flash Update Holddown Timer Split Horizon Poison Reserve

6 IGRP Composite Metric Destination 19.2 kbps Source Bandwidth Delay Reliability Loading MTU

7 IGRP Composite Metric Destination Source Maximum six paths Next hop router closer to destination Within metric variance New route Initial route

8 Configuring IGRP Router igrp 109 network network Router igrp 109 network network Configures IGRP process for network and

9 Configuring IGRP (cont.) Router igrp 71 network router igrp 109 network Router igrp 71 network router igrp 109 network AS AS Configures separate IGRP routing processes for each autonomous system (AS)

10 Configuring IGRP Metric Variance router igrp 109 network Default-metric variance 4 traffic-share balanced router igrp 109 network Default-metric variance 4 traffic-share balanced Configures the IGRP metric variance for load sharing

11 Route Filtering Router (config-router) # Redistribute igrp  Redistributes IGRP routing information into another routing domain Router (config-router) # distribute igrp access-list-number { in | out } [interface-name | routing-process ]  Uses a standard access list to permit or deny routing information

12 Configuring Route Redistribution Router igrp 71 redistribute igrp 109 distribute-list 3 out igrp 109 access-list 3 permit Router igrp 71 redistribute igrp 109 distribute-list 3 out igrp 109 access-list 3 permit AS AS Redistributes routes from AS 109 into AS 71

13 Configuring Route Redistribution (cont.) Router igrp 109 network redistribute rip default-metric distribute-list 10 out rip access-list 10 permit Router igrp 109 network redistribute rip default-metric distribute-list 10 out rip access-list 10 permit RIP AS Redistributes RIP-based routes into IGRP

14 Configuring Route Redistribution (cont.) Router rip network redistribute igrp 109 default-metric 4 distribute-list 11 out igrp Router rip network redistribute igrp 109 default-metric 4 distribute-list 11 out igrp RIP AS Redistributes IGRP routes into RIP network

15 Verifying IGRP Operation Router (config) # Show ip protocols  Display the parameters and current state of the active routing protocol processes Router (config) # Show ip route igrp  Display current IGRP entries in the routing table

16 Summary IGRP is an advanced distance vector routing protocol IGRP uses a composite metric IGRP configuration is straight-forward IGRP supports multiple equal or unequal paths IGRP supports route redistribution