 Hello everyone, myself Mr. Sopayam Madghar working as a student professor in Computer Science and Engineering Department at Walsh and Institute of Technology. Now I welcome to the session on Routing Algorithms ok, it will comes under a network layer of voice reference model, learning outcome at the end of this session students will be able to describe routing algorithm concept. As in the in this video we will discuss about definition of algorithm, types of routing algorithm, there are two types are there that is adaptive routing algorithm and non-adaptive routing algorithm, next optimality principle ok. Let us see one by one in detail about routing algorithm ok. About routing algorithm in this one the main function of the network layer is routing packets from the source machine to the destination machine ok. How we have to transfer by using the network layer concept the routers ok by using the routers we have to transfer the packets and how we have to transfer ok. In most networks packets will requires multiple hopes to make the journey. It means if you are sending the data or packet from one station to another stations it means in networking it will requires more than one hopes it means multiple paths are necessary to transfer the packet. If one path is not working and if something is happened to that particular path the packet may transfer to the alternate paths ok. The algorithm that choose the routes and the data structures that they use are major area of network layer design ok. Here how we have to choose the routers and data structure to transfer the packets ok. The algorithm is set of instructions designed to perform a specific task. Specific task it means here we want to transfer the packets to the different users it means by using this routing algorithm we want to we can transfer the data. What is the algorithm it means it is just instructions designed to perform different task for different task it means transmitting the packets ok. Based on that only they have given two types of routing algorithms types of routing algorithms are first one is adaptive routing algorithm and non-adaptive routing algorithms ok. So, let us see what is the routing algorithm in this one it that is adaptive routing algorithm it is an algorithm it is an algorithm that construct the routing table based on the network condition. It means the different based on the here the user is sending the data or packet to the next user it means we have to prepare the routing table it means how the packet is arrived and how the packet is going or moving to the next user that we have to construct how it can by using adaptive routing algorithm it means then based on the network conditions we have to prepare the or construct the routing table. Adaptive routing algorithm is used by dynamic routing ok and non-adaptive routing algorithms it is an algorithm that construct the static table to determine which node to send the packet it means if the alternate paths are there out of alternate paths how we by using which path if we are sending the data it means that data may reach to the destination safely that we have to find out ok. Next the routing algorithm is that the part of the network layer software reasonable or responsible for deciding which output line and incoming packet should be transmitted on ok. Here by using this one which software is responsible for deciding if you are transmitting the data it means which path is suitable to transfer that packet to the next user that we have to decide ok. Here if the network uses virtual circuit internally the routing decisions are made only when a new virtual circuit is being shut off ok. The latter case is sometimes called session routing because the route remains route remains in force for an entire session ok based on this one how we have to find out what are the different desired properties of the routing algorithms what we have to give you are sending the data from different packet to the different users what are the different points we have to consider what are the different desirable properties we have to consider in this one ok in the routing algorithm first certain properties are desired in our routing algorithm that are we have to find out the correctness and simplicity robustness and then stability fairness efficiency these are the different properties we have to consider by sending the data in by using routing algorithm ok. Now think and write it up if this part can contains one question that is list some differences that a lot of points are there regarding that adaptive and non adaptive routing algorithm in the above part we have discussed only one or two points what are different major differences are there between adaptive and non adaptive algorithm list some differences. Now pass the video and answer the above question ok now we can come to the answer there are total six differences are there first one is a routing adaptive routing algorithm non adaptive routing algorithm in the routing adaptive routing algorithm this algorithm creates a routing table based on the network condition it creates a static table in order to determine when to send packet sign which node we have to ok it is used by dynamic routing here it is used by static routing here in the adaptive routing algorithm we have to use dynamic you may change the data anyway anytime and here we have to use a static routing it is not possible to change any data while transmitting the data in this one that is a non adaptive routing algorithm ok. In this routing decisions are made based on network traffic and topology but in the non adaptive this routing algorithms are not made based on network traffic and topology this one the routing decisions are not static tables these are routing decisions are static tables ok this is categorized into distributed centralized and isolation algorithm isolation algorithm this is categorized into random walks and flooding ok adaptive routing algorithm is more used as compared to non adaptive but whereas in non adaptive algorithm is comparatively less used ok at optimality principle ok the optimality principle states that if router j is one of the optimal path from router j to router k then the optimal path from j to k also falls along the same route it means if they are sending how we have to find optimal path we have to find out it means it is it can also belongs to the same route ok one can take a general statement about the optimal routes without regard to network topology statement is known is known as optimal principle what is optimality principle it can one can make a general statement about optimal routes without regard to network topology statement is this one this concept we can call it as an optimality principle ok. The part of the route from i to j is r 1 and rest of the route is r 2 what is that then you can see here here that is if router better than r 2 existed from j to k it could be concatenated with r 1 to improve the route from i to k contradicting our statement that r 1 and r 2 is optimal here these two diagrams are they just you can see here this network kind sink tree for router this is simple network is there there are so many nodes are there and then here it gets starts from a b c d there are so many nodes are there and the routers are also there we have to send how we have to find out the optimality by using this network it means here they have given sink tree for router here they have considered b as a source by using this one the user may send the data but here the loop may not occur in this one the sink tree in the sink tree ok here the b can send the data to c as well as a also and d and then d 2 c and h c c 2 i c 2 j j 2 e and then m 2 o like this they may transfer the b is if you are considering b as a source then he may transfer the data but loop may not occur in this one ok the set of optimal routes from all source to a given destination form a tree routed at the destination such as such a tree is called sink tree ok means the loops may not occur in the optimality principle here it is continuous sink tree is not necessarily unique ok other trees with the same path lengths may exist ok if we allow all of the possible paths to be chosen that tree becomes more general structure ok called a DAG if we are if we allow all of the possible paths to be chosen that tree becomes more general structure called DAG that is what is full form DAG it means directed a cyclic graph ok DAG have no loops ok this concept we have to use in a sink tree ok we will use sink tree as a convenient short and for both the cases it means sending the data and receiving the data in this one the loops may occur both the cases also dependent on the technical assumptions that the paths do not infer with each other ok like this we have to transfer the data in this one both the cases it means with loop and without loop in this one in the directed by if they are using this one that is DAG or directed a cyclic graph the loop may not occur if you if the while sending the data if the looping is occur the data may not reach to the destination ok this is about the optimality principle ok these are the references I have used for preparing the above ppt ok thank you