HP 6125G HP 6125G & 6125G/XG Blade Switches Layer 3 - IP Routing Confi - Page 63

Router types Router classification The following are OSPF router types and their positions in the AS: • Internal router-All interfaces on an internal router belong to one OSPF area. • Area Border Router (ABR)-An ABR belongs to more than two areas, one of which must be the backbone area. It connects the backbone area to a non-backbone area. The connection between an ABR and the backbone area can be physical or logical. • Backbone router-At least one interface of a backbone router must reside in the backbone area. All ABRs and internal routers in area 0 are backbone routers. • Autonomous System Boundary Router (ASBR)-A router exchanging routing information with another AS is an ASBR, which may not reside on the border of the AS. It can be an internal router or an ABR. Figure 18 OSPF router types Route types OSPF prioritize routes into the following levels: • Intra-area route • Inter-area route • Type-1 external route • Type-2 external route The intra-area and inter-area routes describe the network topology of the AS. The external routes describe routes to external ASs. 53