Basic Concepts Basic Concepts Line Configuration n Topology
Basic Concepts
Basic Concepts Line Configuration n Topology n Transmission Mode n Categories of Networks n Internetworks n
Line Configuration The way two or more communication devices attach to the link n The link = physical pathway that transfers data from one device to another n Point-to-Point n Multipoint n
Point-to-Point link workstation link server workstation link workstation
Multipoint workstation link server workstation Capacity of the channel is shared spatially shared line simultaneously several devices can use the link time-shared line users must take turn
Basic Concepts Line Configuration n Topology n Transmission Mode n Categories of Networks n Internetworks n
Topology n Topology = the way a network is laid out Physically n Logically n Mesh n Star n Tree n Bus n Ring n
Relationship Status n Peer-to-peer n n The devices share the link equally Primary-secondary n One device control traffic and the other must transmit through it Ring and mesh topology peer-to-peer transmission n Star and tree topology primary-secondary n Bus both n
Mesh Advantages: no shared link, each communication carries its own data load robust – if one link is unusable, there are still other links to use privacy and security fault identification and fault isolation -- easy
Mesh n Disadvantages Requires many cables, ports, hardware n N devices require n n N(N-1)/2 physical channels n N-1 I/O ports for each device
Star Central control hub Each device needs only one link, one I/O port Easy to install, reconfigure Less cables Fault detection /isolation easy robust
Tree Central control (Active hub) hub hub
Bus Drop line Cable end Tap Tap backbone Tap
Bus Advantages easy to install less cables Disadvantages fault isolation is difficult to add new devices
Basic Concepts Line Configuration n Topology n Transmission Mode n Categories of Networks n Internetworks n
Transmission Mode Defines the direction of signal flow between two linked devices n Three types n Simplex n Half-duplex n Full-duplex n
Transmission Mode n Simplex Unidirectional, like a one way street n Only one device can transmit, the other only receives n Direction of data server monitor
Transmission Mode n Half-duplex n n n Each station can both transmit and receive but not at the same time When one device is sending, the other can only receive E. g. Walkie-talkie Direction of data at time 1 Direction of data at time 2
Transmission Mode n Full-duplex Both stations can transmit and receive simultaneously n E. g. telephone network n Direction of data at the time
Basic Concepts Line Configuration n Topology n Transmission Mode n Categories of Networks n Internetworks n
Categories of Networks LAN (Local Area Network) n MAN (Metropolitan Area Network) n WAN (Wide Area Network) n
Internetworks n Two or more networks are connected
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