The presence of congestion means the load is greater than the resources available over a network to handle. Generally, we will get an idea to reduce the congestion by trying to increase the resources or decrease the load, but it is not that much of a good idea.There are some approaches for congestion control over a network which are usually applied on different time scales to either prevent congestion or react to it once it has occurred.Admission ControlIt is one of techniques that is widely used in virtual-circuit networks to keep congestion at bay. The idea is do not set ... Read More

Traffic awareness is one of the approaches for congestion control over the network. The basic way to avoid congestion is to build a network that is well matched to the traffic that it carries. If more traffic is directed but a low-bandwidth link is available, congestion occurs.The main goal of traffic aware routing is to identify the best routes by considering the load, set the link weight to be a function of fixed link bandwidth and propagation delay and the variable measured load or average queuing delay.Least-weight paths will then favour paths that are more lightly loaded, remaining all are ... Read More

We will match words in the first DataFrame with words in the second DataFrame. For closest matches, we will use threshold. We took the value of threshold as 70 i.e., match occurs when the strings at more than 70% close to each other.Let us first create Dictionaries and convert to pandas dataframe −# dictionaries d1 = {'Car': ["BMW", "Audi", "Lexus", "Mercedes", "Rolls"]} d2 = {'Car': ["BM", "Audi", "Le", "MERCEDES", "Rolls Royce"]} # convert dictionaries to pandas dataframes df1 = pd.DataFrame(d1) df2 = pd.DataFrame(d2)Now, convert dataframe column to list of elements for fuzzy matching −myList1 = df1['Car'].tolist() myList2 = ... Read More

The presence of congestion means the load is greater than the resources available over a network to handle. Generally we will get an idea to reduce the congestion by trying to increase the resources or decrease the load, but it is not that much of a good idea.Approaches to Congestion ControlThere are some approaches for congestion control over a network which are usually applied on different time scales to either prevent congestion or react to it once it has occurred.Let us understand these approaches step wise as mentioned below −Step 1 − The basic way to avoid congestion is to ... Read More

Token bucket algorithm is one of the techniques for congestion control algorithms. When too many packets are present in the network it causes packet delay and loss of packet which degrades the performance of the system. This situation is called congestion.The network layer and transport layer share the responsibility for handling congestions. One of the most effective ways to control congestion is trying to reduce the load that transport layer is placing on the network. To maintain this network and transport layers have to work together.The Token Bucket Algorithm is diagrammatically represented as follows −With too much traffic, performance drops ... Read More

The network layer is concerned with getting packets from the source all the way to the destination with minimal cost. Unlike the data link layer which has more important goals like just moving frames from one end of a wire to another. The network layer is the lowest layer that deals with end-to-end transmission.Network Layer Design issuesNetwork layer Design issues are as follows −Store and forward packets switchingServices provided to the transport layerImplementation of connectionless servicesImplementation of connection oriented servicesComparison of virtual-circuit datagram networksNow let us see one of the design issues of the network layer.Services provided to the transport ... Read More

Data link layer translates the physical layers raw bit stream into discrete messages called frames. Now the question is how can a frame be transmitted, so the receiver can recognize the start and end frame?TechniquesThe techniques we used to find the start and end frame are −Character countFlag byte with byte stuffingStarting and ending flag with bit stuffingEncoding Violation.Now let us see the Physical layer encoding violation technique.Physical layer encoding violationThis framing method is used only in those networks in which encoding on the physical medium contain some redundancy.Some LANs encode each bit of data by using two physical bits ... Read More

Data link layer translates the physical layers raw bit stream into discrete messages called frames. Now the question is how can a frame be transmitted, so the receiver can recognize the start and end frame?TechniquesThe techniques we used to find the start and end frame are −Character countFlag byte with byte stuffingStarting and ending flag with bit stuffingEncoding Violation.Now let us see the character count technique.Character CountFirst framing method uses a field in the header to specify the number of characters in the frame. When the data link layer at the destination sees the character count, it knows how many ... Read More

Elementary Data Link protocols are classified into three categories, as given below −Protocol 1 − Unrestricted simplex protocolProtocol 2 − Simplex stop and wait protocolProtocol 3 − Simplex protocol for noisy channels.Let us discuss each protocol one by one.Unrestricted Simplex ProtocolData transmitting is carried out in one direction only. The transmission (Tx) and receiving (Rx) are always ready and the processing time can be ignored. In this protocol, infinite buffer space is available, and no errors are occurring that is no damage frames and no lost frames.The Unrestricted Simplex Protocol is diagrammatically represented as follows −Simplex Stop and Wait protocolIn ... Read More

The Data Link layer is located between physical and network layers. It provides services to the Network layer and it receives services from the physical layer. The scope of the data link layer is node-to-node.The following are the design issues in the Data Link Layer −The services that are provided to the Network layer.FramingError controlFlow controlServices to the Network LayerIn OSI each layer uses the services of the bottom layer and provides services to the above layer. The main function of this layer is to provide a well defined service interface over the network layer.Types of ServicesThe services are of ... Read More