1	Interconnecting Cisco Networking Devices Module 10 Optional: OSPF, EIGRP
2	Overview Enhanced Interior Gateway Routing Protocol (EIGRP) Basics Protocol-Dependent Modules Neighbor Discovery Reliable Transport Protocol (RTP) Diffusing Update Algorithm (DUAL) Using EIGRP in Large Networks Enabling and Configuring EIGRP Open Shortest Path First (OSPF) Basics Terminology SPF Tree Calculation Enabling and Configuring OSPF
3	EIGRP Basics Classless, enhanced distance-vector protocol. Sometimes referred to as a ‘Hybrid Routing Protocol’ Cisco proprietary Supports IP, IPX, AppleTalk via Protocol-Dependent Modules Efficient Neighbor discovery Communicates via RTP Path selection via DUAL
4	EIGRP Protocol-Dependent Modules (PDM) Supports the use of multiple network layer protocols Maintains a separate series of tables for each PDM in the routing table
5	EIGRP Neighbor Discovery Before EIGRP routers will exchange routes w/ each other they establish a neighbor relationship These conditions must be matched Hello or ACK received Autonomous System (AS) #s match Identical Metrics (K values)
6	EIGRP Reliable Transport Protocol (RTP) EIGRP will send multicast traffic to 224.0.0.10 by default If it doesn’t get a reply, it will switch to unicast traffic If it still doesn’t get a reply after 16 unicast attempts, the neighbor is declared dead
7	EIGRP Diffusing Update Algorithm (DUAL) The algorithm allows for Backup route determination if one is available Support of VLSM Dynamic Route Recoveries Sending out queries for an alternate route if no route can be found Gives EIGRP the fastest convergence among all protocols
8	Using EIGRP in Large Networks Features that make EIGRP useful in large networks Support for multiple Autonomous Systems (AS) on a single router Support for VLSM and Summarization Route discovery and maintenance Metrics are based on Bandwidth () Delay () Load Reliability Maximum Transmission Unit (MTU) Never been used in calculations, but sometimes a required parameter
9	Enabling and Configuring EIGRP Router(config)# router eigrp 20 Router(config-router)# network 172.16.0.0 Router(config-router)# network 10.0.0.0 Router(config-router)# passive-interface ethernet 0 Router# sh ip route Router# sh ip route eigrp Router# sh ip eigrp neighbors Router# sh ip eigrp topology
10	OSPF Basics Open standards routing protocol Works by using Dijkstra algorithm A shortest path tree is constructed Then the routing table is populated w/ the resulting best paths Fast convergence, though not as fast as EIGRP Supports only IP Routing First true link-state routing protocol
11	OSPF Basics II OSPF should be designed in a hierarchical fashion, which basically means separating a larger network into smaller “areas” Decreases routing overhead Speeds up convergence Confines network instability to single areas of the network
12	OSPF Terminology Link Router ID (RID) Neighbors Adjacency Link State Advertisement (LSA) Designated Router (DR) Backup Designated Router (BDR) OSPF Areas Nonbroadcast Multi-access (NMBA) Point-to-Point Point-to-Multipoint
13	OSPF SPF Tree Calculation Algorithm that reads the topology information and builds a tree
14	Enabling and Configuring OSPF Router(config)# router ospf 1 (# is irrelevant) Router(config-router)# network 10.0.0.0 0.255.255.255 area 0 Router# sh ip route Router# sh ip route ospf Router# sh ip ospf Router# sh ip ospf database Router# sh ip ospf interface Router# sh ip ospf neighbor Router# sh ip protocols
15	Summary Enhanced Interior Gateway Routing Protocol (EIGRP) Basics Protocol-Dependent Modules Neighbor Discovery Reliable Transport Protocol (RTP) Diffusing Update Algorithm (DUAL) Using EIGRP in Large Networks Enabling and Configuring EIGRP Open Shortest Path First (OSPF) Basics Terminology SPF Tree Calculation Enabling and Configuring OSPF