Network statements in Lazy mode & Deep dive into OSPF Network command

During my journey of CCIE, I noticed an OSPF feature worth of sharing. In Core/IGP routing, instead of typing a lot in network commands in OSPF, we can just use network 0.0.0.0 255.255.255.255 and more surprisingly 0.0.0.0 0.0.0.0. Once you enter all zeroes, running-config will convert it to quad 0 followed by quad 255. We can also use 0.0.0.0 0.0.0.0. It just includes all interfaces the same way as if you do 0.0.0.0 255.255.255.255.   Below is the practical demonstration: If the router has all interfaces in a single area, I always use network 0.0.0.0 255.255.255.255 area area-id.    Since, Read More …

Open Shortest Path First (OSPF)

Introduction OSPF is an open source Routing protocol that handles routing for IP traffic standardized in IETF RFC2328. OSPF is classified as an Interior Gateway Protocol (IGP). This means that it distributes routing information between routers belonging to a single Autonomous System. The OSPF protocol is based on link-state or SPF technology. It was designed mainly for the TCP/IP internet environment. Main focus was to produce a protocol that responds quickly to topology changes, with small amounts of control traffic. OSPF is a dynamic routing protocol.  It quickly detects topological changes in the AS (such as router interface failures) and Read More …