In this post, we will understand the difference between network operating system and a distributed operating system.Network Operating SystemThe main object of this system is to provide local services to remote clients.The communication takes place depending on the files.It is more scalable in comparison to Distributed Operating System.It has less fault tolerance.The rate of autonomy in a network operating system is high.It is easy to implement.The nodes of a network operating system can have different operating system.Distributed Operating SystemThe main objective of this system is to manage the resources of the hardware.The communication takes place depending on messages and shared ... Read More

DefinitionIn computer science and mathematics, a directed acyclic graph (DAG) refers to a directed graph which has no directed cycles.ExplanationIn graph theory, a graph refers to a set of vertices which are connected by lines called edges. In a directed graph or a digraph, each edge is associated with a direction from a start vertex to an end vertex. If we traverse along the direction of the edges and we find that no closed loops are formed along any path, we say that there are no directed cycles. The graph formed is a directed acyclic graph.A DAG is always topologically ... Read More

DefinitionThe Dijkstra’s algorithm finds the shortest path from a particular node, called the source node to every other node in a connected graph. It produces a shortest path tree with the source node as the root. It is profoundly used in computer networks to generate optimal routes with the aim of minimizing routing costs.Dijkstra’s AlgorithmInput − A graph representing the network; and a source node, sOutput − A shortest path tree, spt[], with s as the root node.Initializations −An array of distances dist[] of size |V| (number of nodes), where dist[s] = 0 and dist[u] = ∞ (infinite), where u ... Read More

Flooding and fixed routing are methods to transmit data packets from the source to the destination through a number of intermediate routers connected by transmission lines.Flooding is a non-adaptive routing technique following this simple method − when a data packet arrives at a router, it is sent to all the outgoing links except the one it has arrived on.Fixed routing algorithm is a procedure that lays down a fixed route or path to transfer data packets from source to the destination. The route is a mathematically computed best path, i.e. “least–cost path” that the packet can be routed through. The ... Read More

Routing Algorithms − A routing algorithm is a procedure that lays down the route or path to transfer data packets from source to the destination. There can be many paths from the source to the destination; routing algorithm mathematically computes the best path, i.e. “least – cost path”. Routing algorithms are broadly classified into adaptive and non-adaptive routing algorithms.Adaptive Routing Algorithms − Also known as dynamic routing algorithms, they makes routing decisions dynamically depending on the network conditions. It constructs the routing table depending upon the network traffic and topology.Non-Adaptive Routing Algorithms − Also known as static routing algorithms, they ... Read More

DefinitionSink trees of a given node in a computer network is a tree formed by connecting the node with all the other nodes of in the network with the optimal path, or more precisely the shortest path. Or, in other words, a sink tree is a minimal cost tree formed with the given node as the destination and all other nodes as sources. A popular measure for the path or the cost is the number of hops.ExplanationThe sink tree follows from the optimality principle. According to it, in a network of routers for data transmission, if a router ‘J’ lies ... Read More

Adaptive routing algorithms, also known as dynamic routing algorithms, makes routing decisions dynamically while transferring data packets from the source to the destination. These algorithms constructs routing tables depending on the network conditions like network traffic and topology. They try to compute computes the best path, i.e. “least – cost path”, depending upon the hop count, transit time and distance.Types of Adaptive Routing AlgorithmsThe three popular types of adaptive routing algorithms are shown in the following diagram −Centralized algorithm − In centralized routing, one centralized node has the total network information and takes the routing decisions. It finds the least-cost ... Read More

Non-adaptive routing algorithms, also known as static routing algorithms, do not change the selected routing decisions for transferring data packets from the source to the destination. They construct a static routing table in advance to determine the path through which packets are to be sent.The static routing table is constructed based upon the routing information stored in the routers when the network is booted up. Once the static paths are available to all the routers, they transmit the data packets along these paths. The changing network topology and traffic conditions do not affect the routing decisions.Types of Non − adaptive ... Read More

Virtual – circuit and datagram networks are categories of packet switching network. In virtual circuits, a virtual path is established between the source and the destination systems through which the data packets are transferred from the source to the destination. In the other hand, in datagram networks, each data packet called datagram contain adequate header information so that they can be individually routed by all intermediate network switching devices to the destination.DifferencesIssueVirtual – Circuit NetworksDatagram NetworksConnectivityVirtual – circuits are connection oriented networks.Datagram networks are connectionless.PathIn these networks, the path between the source and the destination nodes that is followed by ... Read More

Multiprotocol Label Switching (MPLS) is a routing technique that augments speed and control of the network traffic by directing data from one node to the next node based on short path labels. Instead of being routed using long network addresses, the data packets are routed through path labels that identify virtual paths between the nodes rather than endpoints. MPLS speeds up traffic flows by avoiding complex lookups in the routing table at each node as in conventional routing algorithms.MPLS is a scalable and protocol-independent routing technique. It works with Internet Protocol (IP), Ethernet, Frame Relay and Asynchronous Transport Mode (ATM). ... Read More