Related Directory Categories
- Topology (245)
- Events (85)
- Past Events (74)
- Knot Theory (33)
- Algebraic Topology (29)
- General Topology (23)
- People (18)
- Research Groups (13)
- Software (12)
- Topological (11)
Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Redundant topologies
From Wikipedia, the free encyclopedia
Contents |
A goal of redundant topologies is to eliminate network downtime caused by a single point of failure. All networks need redundancy for enhanced reliability. Network reliability is achieved through reliable equipment and network designs that are tolerant to failures and faults. Networks should be designed to reconverge rapidly so that the fault is bypassed.
the picture to the right shows a mesh network topology .Devices are connected with many redundant interconnections between network nodes. In a true mesh topology every node has a connection to every other node in the network. this is a prime example of a redundant topology.
in the image if router A was to fail on token ring 4 station Z would still have connectivity with station X via router B. furthermore, each router has two points, legs if you will, at which to keep redundancy.
Redundant network topologies are designed to ensure that networks continue to function in the presence of single points of failure. Work is interrupted less often for users because the network continues to function. Any interruptions that are caused by a failure should be as short as possible. Reliability is increased by redundancy. A network that is based on switches or bridges will introduce redundant links between those switches or bridges to overcome the failure of a single link. These connections introduce physical loops into the network. These bridging loops are created so if one link fails another can take over the function of forwarding traffic. In this transition, any unknown destination for currently flowing traffic is flooded over every port except the one it originated from. At layer 2, headers dont have a TTL (time to live) value. If a frame is sent into a layer 2 looped topology of switches, it would loop forever causing serious overhead on the bandwidth of the network.
The ultimate solution is to allow physical loops, but create a loop free logical topology. This is achieved using STP (spanning tree protocol).[1]. Simple put, STP applies a specific algorithm to the network based on its topology with the result of a loop free logical topology.
- redundant topologies. Cisco Systems (2006-10-23). Retrieved on 2007-02-28.