Interconnect multiple OSPF regions

Interconnect multiple OSPF regions to solve the problem of frequent calculation of the shortest path priority (SPF) algorithm, large route tables, and large link status tables, OSPF is designed to divide large networks into multiple regions. It is also called a systematic route. Systematic routing enables us to divide a large network (Autonomous System) into a small network www.2cto.com OSPF that is called a region. The systematic topology structure has the following advantages: lSPF computing frequency reduced l smaller route table l link status update (LSU) load reduced OSPF router type: l internal router l main router l Region Border Router (ABR) l type of the autonomous system border router (ASBR) area l standard region l main region l not included area l completely not included area l how does the data packet from not included area pass through multiple regions: l if the destination of the data packet is an external network, it will be forwarded by the internal router of the region to the internal router of the destination; l if the destination of the data packet is a network outside the region, then it must go through the following path ------ data packets are sent from the source network to An ABR ------ the ABR sends data packets outside the trunk area to the destination network ABR ------ the destination ABR forwards the data packets to the destination network virtual link in the domain two conditions: l it must be created on two AB nodes in the same area after the edge. Between R and l, one of the two BRS must be connected to the trunk region router without special commands used to activate the functions of the ABR or ASBR. The router assumes this role when it is connected to the region. The basic configuration steps of OSPF are as follows: l enable OSPF router (config) on the router) # router ospf process-id l indicates which IP networks on the router are used as part of OSPF (config-router) # network address wildcard-mask area-id l (any option) if a router interface is connected to a non-OSPF network, perform the corresponding configuration steps. To further reduce the number of Route tables, we can create a completely unused area, which is a proprietary feature of CISCO. Www.2cto.com Router ospf 200 use process ID 200 to enable OSPFnetwork 10. x. x. X 0.0.0.0 area 0 specifies the interface for running OSPF and the area x range 192.168.X.0 255.255.255.0. The inductive address area X stub [no-summary] configures an area as an area that is not section or is completely section. x virtual-link 192.168.x.49 create an OSPF virtual link area x nssa configure an area as an unassociated area (NSSA) summary-address 172.16.0.0 255.255.0.0 publish external addresses to OSPFshow ip ospf display general information about OSPF routing process show ip ospf neighbor display OSPF neighbor information show ip ospf database display OSPF link status database show ip ospf interface shows specific OSPF information about an interface show ip ospf virtual-links shows the status of the OSPF virtual link debug ip ospf display involves establishing or removing an OSPF adjacent Link event