Editing Network topology (section)

==Centralization==
The '''[[star topology]]''' reduces the probability of a network failure by connecting all of the peripheral nodes (computers, etc.) to a central node.  When the physical star topology is applied to a logical bus network such as [[Ethernet]], this central node (traditionally a hub) rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, sometimes including the originating node. All [[peripheral]] nodes may thus communicate with all others by transmitting to, and receiving from, the central node only.  The [[failure]] of a [[transmission line]] linking any peripheral node to the central node will result in the isolation of that peripheral node from all others, but the remaining peripheral nodes will be unaffected. However, the disadvantage is that the failure of the central node will cause the failure of all of the peripheral nodes.

If the central node is ''passive'', the originating node must be able to tolerate the reception of an [[echo]] of its own transmission, delayed by the two-way [[round-trip time|round trip]] [[transmission time]]  (i.e. to and from the central node) plus any delay generated in the central node. An ''active'' star network has an active central node that usually has the means to prevent echo-related problems.

A '''[[tree topology]]''' (a.k.a. '''hierarchical topology''') can be viewed as a collection of star networks arranged in a [[hierarchy]].  This [[tree structure]] has individual peripheral nodes (e.g. leaves) which are required to transmit to and receive from one other node only and are not required to act as repeaters or regenerators.  Unlike the star network, the functionality of the central node may be distributed.

As in the conventional star network, individual nodes may thus still be isolated from the network by a single-point failure of a transmission path to the node. If a link connecting a leaf fails, that leaf is isolated; if a connection to a non-leaf node fails, an entire section of the network becomes isolated from the rest.

To alleviate the amount of network traffic that comes from broadcasting all signals to all nodes, more advanced central nodes were developed that are able to keep track of the identities of the nodes that are connected to the network.  These [[network switch]]es will ''learn'' the layout of the network by ''listening'' on each port during normal data transmission, examining the [[data packets]] and recording the address/identifier of each connected node and which port it is connected to in a [[lookup table]] held in memory. This lookup table then allows future transmissions to be forwarded to the intended destination only.

Daisy chain topology is a way of connecting network nodes in a linear or ring structure. It is used to transmit messages from one node to the next until they reach the destination node.

A daisy chain network can have two types: linear and ring. A linear daisy chain network is like an electrical series, where the first and last nodes are not connected. A ring daisy chain network is where the first and last nodes are connected, forming a loop.