Shortest path

 The  dijkstra algorithms  four steps to discover what it called  the shortest path  tree .

a.The algorithm  beings  to build  the tree identifying  its root. The root  of each router tree is the  router itself. The algorithm them attaches all nodes  that can  be reached from that  root in other words. All of the other neighbour  nodes and are  are temporary at this step.

b.The algorithm compares the tree temporary acres and identifies the are with the  lowest  commutative cost. This are and the node to which it  connecters are now a permanent part of  shortest path  tree.

c.The  algorithm examines the database  and identifies every node that  can be  reached from it  chosen  node. These nodes  and their  arcs are added temporarily to the tree.

d.The last  two  steps  are repeated until every node  in the network  has become  a permanent part of the tree. The only  permanent  arcs are those  that represent the shortest route to every  node.

The cost number  next to  each node  represents the cumulative cost  from  the root  node  not the cost of the individual arc. The second  third  steps  repeated until  four more  nodes  have  becomes  permanent.