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Chapter 8 -The Routing Table: A Closer Look CCNA Exploration 4.0 Objectives • • • Describe the various route types found in the routing table structure. Describe the routing table lookup process. Describe routing behavior in routed networks. Học viện mạng Bach Khoa - Website: www.bkacad.com Introduction • Chapter Focus - Structure of the routing table. - Lookup process of the routing table. - Classless and classful routing behaviors. Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure Học viện mạng Bach Khoa - Website: www.bkacad.com Lab Topologies Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure • Routing table entries come from the following sources – – – Directly connected networks Static routes Dynamic routing protocols Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure Level 1 Routes • As soon as the no shutdown command is issued the route is added to routing table Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure • Cisco IP routing table is a hierarchical structure.The reason for this is to speed up lookup process Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure • A level 1 route is a route with a subnet mask equal to or less • than the classful mask of the network address. 192.168.1.0/24 is a level 1 network route, because the subnet mask is equal to the network's classful mask. /24 is the classful mask for class C networks, such as the 192.168.1.0 network. A level 1 route can function as a: – Default route - A default route is a static route with the address 0.0.0.0/0. – Supernet route - A supernet route is a network address with a mask less than the classful mask. – Network route - A network route is a route that has a subnet mask equal to that of the classful mask. A network route can also be a parent route. Parent routes will be discussed in the next section. Học viện mạng Bach Khoa - Website: www.bkacad.com Routing Table Structure Ultimate Route • The level 1 route 192.168.1.0/24 can be further defined as an ultimate route. An ultimate route is a route that includes: – Either a next-hop IP address (another path) – And/or an exit interface Học viện mạng Bach Khoa - Website: www.bkacad.com