CCNA,CCNP,CCIE Blogs

Explain Border Gateway Protocol (BGP) ? Border Gateway Protocol advertises, learns and chooses the best paths inside the global Internet. When two ISPs connect, they typically use BGP to exchange routing information. Enterprises also sometimes uses BGP to exchange routing information with ISPs, allowing the Enterprise routers to learn Internet routes. when we have multiple Internet connections and we want to influence some packets to take one path and some packets to take another we use BGP. Can Routers on different subnet become BGP neighbors? BGP does not require neighbors to be attached to the same subnet. Instead, BGP routers use a TCP connection between the routers to pass BGP messages allowing neighboring routers to be on the same or different subnet. What TCP port number BGP use for connection? BGP uses TCP port 179 for the connection. Difference between eBGP and iBGP neighbor? In iBGP, neighborship is formed between routers within the same AS (autonom...

What is OSPF Routing Protocol? Open shortest path first is an Open Standard Link State routing protocol which works by using Dijkastra algorithm to initially construct the shortest paths and follows that by populating the routing table with resulting best paths. What are the steps required to change Neighborship into adjacency? 1.Two-way communication (using Hello Protocol). 2.Database Synchronization which means exchange of Database Description (DD) packets, Link State Request (LSR) packets, Link State Update (LSU) packets. After Database synchronization is complete, the two routers are considered adjacent. Explain LSA (Link-State Advertisement), LSU (Link State Update) and LSR (Link State Request)? The LSAs (Link-State Advertisements) are used by OSPF routers to exchange routing and topology information. When two neighbors decide to exchange routes, they send each other a list of all LSAs in their respective topology database. Each router then checks its topolog...