t route A host route is a route to a host. In other words, the route is not to a network. Host routes have a subnet mask of 255.255.255.255 and a prefix length of /32. Subnet A subnet is a portion of a major network. The subnet mask is used to determine the size of the subnet. 10.10.10.0/24 (255.255.255.0) is a subnet. Summary (group of subnets) A summary route is a single route that references a group of subnets. 10.10.0.0/16 (255.255.0.0) would be a summary, provided that subnets with longer masks (such as 10.10.10.0/24) existed. Major network A major network is any classful network, along with its native mask. 10.0.0.0/8 (255.0.0.0) is a major network. Supernet (group of major networks) A supernet is a single route that references a group of major networks. For example, 10.0.0.0/7 is a supernet that references 10.0.0.0/8 and 11.0.0.0/8. Default route A default route is shown as 0.0.0.0/0 (0.0.0.0). This route is also called the route of last resort. This is the route that is used when no other route matches the des- tination IP address in a packet. The IP Routing Table To show the IP routing table, use the show ip route command: R2#sho ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, 0 - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1 L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route The IP Routing Table Gateway of last resort is 11.0.0.1 to network 0.0.0.0 172.16.0.0/16 is variably subnetted, 6 subnets, 2 masks 172.16.200.0/23 is a summary, 00:56:18, Nullo 172.16.200.0/24 is directly connected, Loopback2 172.16.201.0/24 is directly connected, Serialo/o 172.16.202.0/24 is directly connected, Loopback3 172.16.100.0/23 is directly connected, Loopback4 172.16.101.0/24 [90/2172416] via 11.0.0.1, 00:53:07, FastEthe