Thursday, October 15, 2009

Hybrid topologies


Different topologies may be interconnected to form subnets to a main network. It is possible, for example, to connect a star, a hub and a ring together beneath another star topology network.

Tree


A tree topology is a variation on a star. In this case the central hub might connect to a number of secondary hubs forming a sort of hierarchy of stars. Secondary hubs may be passive or active devices. An active hub acts as a repeater and amplifier for the signals in each direction. This is ideal for networks with remote nodes as link distances can be effectively lengthened without attenuation. A passive hub supplies connections only between the next hub and the nodes below.


Advantages:

  • Secondary hubs increase the number of devices that may be part of the network
  • Hubs can be used to prioritize and isolate traffic on different parts of the network.
  • Other advantages as per star topology

Mesh Topology


A mesh topology is a network topology in which each communicating node is directly connected to all other nodes.
Or
Mesh topology provides each device with a point-to-point connection to every other device in the network. These are most commonly used in WAN's, which connect networks over telecommunication links. Mesh topologies use routers to determine the best path.
Mesh networks provide redundancy, in the event of a link failure; meshed networks enable data to be routed through any other site connected to the network. Because each device has a point-to-point connection to every other device, mesh topologies are the most expensive and difficult to maintain.

Advantages:

  • Dedicated links eliminate congestion due to excessive traffic.
  • Robust as one damaged link will not cripple the network.
  • Point-to-point connections make fault isolation and identification simple.

Disadvantages:
  • High number of connections requires large number of network ports and large amounts of cabling.
  • Wiring bulk may exceed space available.
  • Duplication of hardware becomes expensive

Tag

Assignment Lanka Tag Cloud
Computer Networks The History of Local Area Networks, LAN, The Topologies of a Networks, LANs describe different types of transmission Medias, Local Area Networks Access Methods, Carrier Sense Multiple Access with Collision Detect, Development of LAN Technologies. LAN -Token Ring, LAN Ethernet Digital, LAN - Ethernet Sun microsystems, LAN - Ethernet Mixed Environment, LAN - Token Ring was introduced by IBM LAN - IBM implementation of Token Ring, Token Ring Novell, LAN Token Ring - in a mixed environment, LAN - Fiber Distributed Data Interface, LAN - ATM, LAN Components, LAN Switching Methods, Virtual Local Area Network, Port based VLAN, Mac based VLAN, Protocol based VLAN, User Base VLAN, PC networks Components, PC networks Shared resources, PC Network operating systems, PC networks Novell Netware, PC networks Windows NT, PC networks IBM LAN Server Computer Programming Languages HTML Language, The Generations of Programming Languages, Different types of High Level Languages, Different types of High Level Languages Disadvantages
Computer Networks - IBM LAN Server, Windows NT Networks, Novell Netware, Network operating systems, Networks Shared, Networks Components, User Base, Protocol based, Mac based, Port based, VLAN, LAN Switching, LAN Components, ATM, Fiber Data, Token Ring, Token Ring Novell, IBM implementation, Ethernet, Sun microsystems, Ethernet Digital, Token passing, LAN Technologies, CSMA/CD, Access Methods, Transmission, Networks, The History of Local Area Networks, LAN