In the topology above, routers R1 and R2 are the ABRs interfacing with backbone area 0   Area 1 in this topology has been configured as NSSA this time. My earlier topology referenced a Totally NSSA area.     As mentioned earlier, NSSA configuration in OSPF allows redistribution to occur within the NSSA area.   … Continue reading OSPF NSSA


IP Routing Process

IP routing process is a fundamental concept in networks. Having a clear understanding of IP routing process helps network engineers troubleshoot complex network problems. A good hold of this concept also helps determine end to end traffic flow from any given source IP towards target IP. Below are key steps when traffic from source tries … Continue reading IP Routing Process

OSPF – Auto Cost Reference Bandwidth feature in Cisco IOS

  In the case of OSPF, the OSPF metric – Cost is inversely proportional to interface bandwidth. Meaning, the higher bandwidth link on your device will have lower cost. But OSPF by default is unable to differentiate the cost properly for a device that has both TenG and Gig interfaces. The reason why OSPF is … Continue reading OSPF – Auto Cost Reference Bandwidth feature in Cisco IOS