This is another type of static algorithm.
the main concept of flooding is to sent every incoming packet on a line to every other outgoing line except the line it arrived on.
flooding generates a large no.of duplicate packets, sometimes infinite unless we may take certain measures.
the measures are as follows:-
- one measure is use of hop count in the header of each packet and decrement this count at each hop when count reaches to zero discard the packet.
- How to take this hop count is another problem. Generally it is set to the length of path from source to destination and in worst cases the full diameter of the subnet.
- another way is avoid sending a packet more than once through a router this is possible by using sequence no.
- i.e, a source router (which generates packets) can put a sequence no. to each packet and each router will maintain a list of sequence nos. and if sees a packet with same sequence no in the list that packet is discarded (not flooded).
another way of flooding is of use selective flooding.
i.e, with this the router wouldn’t send every incoming packet on every line instead the router will send packets in a particular direction only.
i.e, east bound packets are sent on east side routers and similarly on west side by west side routers.
even flooding is cumbersome, it has some uses
- used in military applications.
- used in distributive data base applications in which to update all data bases concurrently.
- used in broadcast Routing.
flooding is used rather than any other algorithm since flooding chooses shorter path between two nodes where other algorithms may not.