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

Virtual – circuit network is a category of packet switching network, where a virtual path is established between the source and the destination systems for data communication to occur. This path appears to the user as if it is a dedicated physical path, but actually is a logical circuit allocated from a managed pool of circuit resources as per traffic requirements. The network resources forming parts of this path can be shared by other communications, however, is not visible to this user.Features of Virtual – Circuit NetworkVirtual – circuit switching is done at the network layer of the communication system.In ... Read More

Virtual – circuit network is a category of packet switching network, where a virtual path is established between the source and the destination systems for data communication to occur. This path appears to the user as if it is a dedicated physical path, but actually is a logical circuit allocated from a managed pool of circuit resources as per traffic requirements. The network resources forming parts of this path can be shared by other communications, however, is not visible to this user.Phases of Virtual - Circuit TransmissionThere are three phases of transmission by virtual circuits, set up, data transfer and ... Read More

In a connectionless communication systems, datagram refers to the smallest unit via which data is transmitted. Datagrams are data packets which contain adequate header information so that they can be individually routed by all intermediate network switching devices to the destination. These networks are called datagram networks since communication occurs via datagrams. They exist in packet switching networks.Features of Datagram NetworksDatagram switching is done at the network layer of the communication system.In datagram networks, each data packet or datagram is routed independently from the source to the destination even if they belong to the same message. The network treats the ... Read More

In packet switching networks using datagrams, datagrams are data packets which contain adequate header information so that they can be individually routed by all intermediate switching devices to the destination. These networks are called datagram networks since communication occurs via datagrams.Routing PrincipleIn datagram networks, each data packet is routed independently from the source to the destination even if they belong to the same message. No prior resource or channel allocation is done for the individual packets. As the datagrams are treated as independent units, no dedicated path is fixed for data transfer. Each datagram is routed by the intermediate routers ... Read More

In telecommunications, store − and − forward packet switching is a technique where the data packets are stored in each intermediate node, before they are forwarded to the next node. The intermediate node checks whether the packet is error−free before transmitting, thus ensuring integrity of the data packets. In general, the network layer operates in an environment that uses store and forward packet switching.Working PrincipleThe node which has a packet to send, delivers it to the nearest node, i.e. router. The packet is stored in the router until it has fully arrived and its checksum is verified for error detection. ... Read More

The network layer or layer 3 of the OSI (Open Systems Interconnection) model is concerned delivery of data packets from the source to the destination across multiple hops or links. It is the lowest layer that is concerned with end − to − end transmission. The designers who are concerned with designing this layer needs to cater to certain issues. These issues encompasses the services provided to the upper layers as well as internal design of the layer.The design issues can be elaborated under four heads −Store − and − Forward Packet SwitchingServices to Transport LayerProviding Connection Oriented ServiceProviding Connectionless ... Read More

The main function of the network layer or layer 3 of the OSI (Open Systems Interconnection) model is delivery of data packets from the source to the destination across multiple hops or links. It also controls the operation of the subnet.The functions are elaborated as below −When data is to be sent, the network layer accepts data from the transport layer above, divides and encapsulates it into packets and sends it to the data link layer. The reverse procedure is done during receiving data.The network layer is responsible for routing packets from the source host to the destination host. The ... Read More