HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 3 - IP Routing Confi - Page 12

80.1.1.0/24 ... OSPF 10 2 80.1.1.1 Vlan13 A route entry includes the following key items: • Destination-IP address of the destination host or network. • Mask-Mask length of the IP address. • Pre-Preference of the route. Among routes to the same destination, the one with the highest preference is optimal. • Cost-If multiple routes to a destination have the same preference, the one with the smallest cost is the optimal route. • NextHop-Next hop. • Interface-Output interface. Dynamic routing protocols Dynamic routing protocols dynamically collect and report reachability information to adapt to topology changes. They are suitable for large networks. Compared with static routing, dynamic routing protocols require more resources, and are complicated to configure. Dynamic routing protocols can be classified based on different criteria, as shown in Table 2: Table 2 Dynamic routing protocols Criterion Optional scope Routing algorithm Destination address type IP version Categories • Interior gateway protocols (IGPs)-Work within an AS. Examples include RIP, and OSPF. • Exterior gateway protocols (EGPs)-Work between ASs. The most popular one is BGP. • Distance-vector protocols-RIP and BGP. BGP is also considered a path-vector protocol. • Link-state protocols-OSPF. • Unicast routing protocols-RIP, OSPF, and BGP. • Multicast routing protocols-PIM-SM and PIM-DM. • IPv4 routing protocols-RIP, OSPF, and BGP. • IPv6 routing protocols-RIPng, OSPFv3, and IPv6 BGP. NOTE: An AS refers to a group of routers sharing the same routing policy and working under the same administration. Routing preference Different routing protocols can find different routes to the same destination. However, not all of those routes are optimal. For route selection, routing protocols, direct routes, and static routes are assigned different preferences. The route with the highest preference is preferred. 2