ARP Protocol ARP Role Address Resolution Protocol (ARP) is a very fundamental protocol in computer networking.  When a PC wants to send a message over the network, it has to encapsulate the…

OSPF Areas And LSA Types Quick Definition: Open the shortest path first (OSPF) areas to help break up your networks and routers and find the shortest and most efficient route from…

LSA in OSPF A router’s Link-State Database stores LSAs that are received (LSDB). The Shortest Path First (SPF) algorithm is used by OSPF to determine the optimum routes for each…

LSA Types 1,2 and 3 OSPF learns the topology by exchanging link-state advertisements (LSAs). Engineers preparing for the CCNA exam are often intimidated by the LSA concept and either do…

OSPF Network Types Why does OSPF need network types?Routers can be connected via various types of WAN services. Many old and new WAN technologies can provide IP connectivity between devices.…

OSPF Metric - Cost OSPF Metric - Cost This lesson discusses how OSPF determines the best paths to destinations using its metric called "OSPF Cost". It is a fundamental concept…

Configuring Single-Area OSPF network Lab Initial StateWe use the topology shown in the diagram below. Seven network devices are located at three locations: the data center, large, and small branches.…

OSPF Passive Interface Why do we need an OSPF passive interface?A router often does not need to form neighbor relationships on every interface. For example, the router in the diagram below…