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Network Topologies & Devices. Star Topology. Star Topology. Star Networks are one of the most common network topologies. consists of one central switch , hub or computer, which acts as a conduit to transmit messages.
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Star Topology • Star Networks are one of the most common network topologies. • consists of one central switch, hub or computer, which acts as a conduit to transmit messages. • reduces the chance of network failure by connecting all of the systems to a central node.
Star Topology Advantages • Better performance • Isolation of devices • Benefits from centralization • Easy to detect faults and to remove parts.
Star Topology Disadvantages • High dependence of the system on the functioning of the central hub • Failure of the central hub renders the network inoperable
Bus Topology • In Bus topology, all the nodes (computers as well as servers) are connected to the single cable by the help of interface connectors. • Central cable is the backbone of the network. • Every workstation communicates with the other device through this Bus.
Bus Topology Advantages • Failure of one of the station does not affect others. • Good compromise over the other two topologies as it allows relatively high rate of data transmittion. • Well suited for temporary networks that must be set up in a hurry. • Easy to implement and extend.
Bus Topology Disadvantages • Does not cope well with heavy traffic rates • Difficult to administer/troubleshoot. • Limited cable length and number of stations. • A cable brake can disable the entire network; no redundancy. • Maintenance cost may be higher in the long run.
Mesh Topology • Mesh topologies are important for large-scale peer-to-peer systems that use low-power transceivers. • Every computer that has to be connected to the network is connected to every computer that is available in the network.
Mesh Topology • Mesh topology is best when the network setup is required to be active 24 x 7. • Slightly complicated as compared to other network topologies. • concept of mesh topology is implemented while configuring Routers in production environments.
Tree Topology Advantages • It is most suitable for large networks where ring and star topologies are not efficient. • Since it divides the network in sub-parts, so it becomes more manageable • There is no hassle in either expanding or removing the nodes. • For individual segments there is dedicated line wiring to the local hub.
Tree Topology Disadvantages • The network is vulnerable as it is wholly dependent on the central hub. • If the network becomes extremely large it becomes difficult to manage.
Ring Topology Logical ring • Meaning that data travels in circular fashion from one computer to another on the network. • Typically FDDI, SONET or Token Ring technology are used to implement a ring network. • Ring networks are most commonly wired in a star configuration. • Token Ring has multi-station access unit (MSAU),equivalent to hub or switch. MSAU performs the token circulation internally.
Hybrid Topology • It is a mixture of two or more different topologies. • Combination of topologies is done according to the requirements of the organization. • e.g. Star-Ring, Star-Bus topology etc.
Hub • A hub joins multiple computers form a single network segment. • It is a Layer 1 devices in the OSI model. • A hub simply receives incoming packets, possibly amplifies the electrical signal, and broadcasts these packets out to all devices on the network. • They do not read any of the data passing through them and are not aware of their source or destination
Hub Three different types of hubs exist • Passive • Active • Intelligent
Switch The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer -2) of the OSI model.
Switch • Switch Connects network segments or network devices. • Switch receives a message from any device connected to it and then transmits the message only to the device for which the message was meant. • It is more intelligent device than a hub. • Switches are sometimes called “multi-port bridges”.
Router A router is a device that forwards data packets between computer networks, creating an overlay internetwork.
Router • It uses Routing table or Routing policies to direct the packets to its destination. • Access routers • Distribution routers • Security issues with routers
Bridge • A bridge device filters data traffic at a network boundary. • Bridges reduce the amount of traffic on a LAN by dividing it into two segments.
Bridge • Operate at the data link layer. • Inspect incoming traffic and decide whether to forward or discard it.
Bridge Advantages • Simple bridges are inexpensive. • Simple configuration modes. • Isolate collision domains with micro-segmentation. • It increase network length. • Access control and network management capabilities. • Bandwidth scales as network grows.
Bridge Disadvantages • Does not limit the scope of broadcast. • Does not scale to extremely large networks. • Extremely large networks cannot rely on bridges. • Buffering and processing introduces delays.
Conclusion In today’s world people want their information to be shared, sent and received quickly. Such network topologies and devices make it real and possible for us.
