After studying this chapter you will be able to: Describe the various route types found in the routing table structure, describe the routing table lookup process, describe routing behavior in routed networks. | The Routing Table: A Closer Look Routing Protocols and Concepts – Chapter 8 Describe the various route types found in the routing table structure. Describe the routing table lookup process. Describe routing behavior in routed networks. Objectives Chapter focus: Structure of the routing table. Lookup process of the routing table. Classless and classful routing behaviors. Introduction Lab topology 3 router setup: R1 and R2 share a common network with subnets R2 and R3 are connected by the network R3 also has a subnet, which is disconnected, or discontiguous, from the network that R1 and R2 share Routing Table Structure Routing table entries come from the following sources: Directly connected networks Static routes Dynamic routing protocols Routing Table Structure Level 1 routes As soon as the no shutdown command is issued the route is added to routing table Routing Table Structure Cisco IP routing table is a . | The Routing Table: A Closer Look Routing Protocols and Concepts – Chapter 8 Describe the various route types found in the routing table structure. Describe the routing table lookup process. Describe routing behavior in routed networks. Objectives Chapter focus: Structure of the routing table. Lookup process of the routing table. Classless and classful routing behaviors. Introduction Lab topology 3 router setup: R1 and R2 share a common network with subnets R2 and R3 are connected by the network R3 also has a subnet, which is disconnected, or discontiguous, from the network that R1 and R2 share Routing Table Structure Routing table entries come from the following sources: Directly connected networks Static routes Dynamic routing protocols Routing Table Structure Level 1 routes As soon as the no shutdown command is issued the route is added to routing table Routing Table Structure Cisco IP routing table is a hierarchical structure The reason for this is to speed up lookup process Routing Table Structure Level 1 routes: Have a subnet mask equal to or less than the classful mask of the network address Level 1 routes can function as: Default routes Supernet routes Network routes Routing Table Structure Level 1 routes: Ultimate routes includes either: A next-hop address OR An exit interface Routing Table Structure Parent and child routes: A parent route is a level 1 route A parent route does not contain any next-hop IP address or exit interface information Routing Table Structure Automatic creation of parent routes: Occurs any time a subnet is added to the routing table Child routes: Child routes are level 2 routes Child routes are a subnet of a classful network address Routing Table Structure Level 2 child routes contain route source and the network address of the route Level 2 child routes are also considered ultimate routes Reason: they contain the next hop address and/or exit interface Routing Table
