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ATM (asynchronous transfer mode) is a circuit switched technology that slices digital data into 53-byte cells and transmits them over a lower level transmission medium. By licing the data into such small packets and then using very high speed switching electronics, precise control of quality of service can be achieved. ATM is traffic type agnostic - voice, data and video may be mixed upon a common network infrastructure and each may co-exist with interfering with another. In the TANet network, national ATM services are deployed on top of both WDM and SDH layers.
Fibernet's approach to ATM is comprehensive and is NOT designed to simply replicate existing private circuit tariffs using PVC technologies, but to offer our clients complete control over their ATM network, revealing all of it's many features, advantages and benefits.
There are now more than 15 core switches in the TANet backbone with many more in edge locations. Each of the following ATM characteristics can be specifically engineered to meet individual customer needs.
| PVC |
Permanent Virtual Circuits. Permanently established paths between two network points. PVCs are further defined by individual quality of service criteria that describe the bandwidth available to that circuit and under what conditions it is maintained. |
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| SPVC |
"Smart" Permanent Virtual Circuits - PVCs that automatically re-route in the event of network failure |
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| SVC |
Switched Virtual Circuits - paths between two network points that are only established when required and are closed down when no longer needed. SVCs are also further described by use of quality of service criteria. |
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| PVP |
Permanent Virtual Paths ("Containers" for PVCs & SVCs that may be given their own QOS attributes). PVPs protect individual clients from the activity of others and provide a convenient way of bundling all of an individual customers VCs on a given route into one manageable "container". |
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| SPVP |
As with SPVCs, "Smart" PVPs re-route automatically in the event of network failure. |
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| MPOA |
Multi-Protocol over ATM - currently for TCP/IP mapping. |
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| PNNI |
Private Network to Network interface - an ATM routing protocol enabling load balancing and dynamic re-routing. UNI interfaces are also available to users of private ATM networks built using TANet transmission infrastructure. |
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| Standards |
Compliance TANet complies to ATM Forum specifications including UNI 3.0, 3.1 & 4.0 and PNNI 1.0. |
Hierarchical PNNI automatically discovers the ATM network topology, creating a multi-level "loop free" hierarchy of PNNI peer groups. This allows the network to scale to enormous sizes without choking on network-wide topology updates; Split-switch PNNI enables Fibernet to easily construct virtual ATM networks for different customers whilst providing a gateway between them. Accelerated remote failure detection - enables rerouting around failures in milliseconds. Prioritisation of recovered traffic enables delay sensitive traffic (for example, CBR based voice) to "repaired" and re-routed in advance of data traffic. VBR - CBR Load Balancing performance - The TANet network load balances VBR, UBR and CBR traffic within PNNI peer groups Static, Resilient multicast - TANet's new Point to Multipoint SPVC capability allows us to build bandwidth conserving trees that can deliver audio and video to specific receiving devices whilst protecting and conserving overall network bandwidth.
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