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Traffic engineering Traffic grooming Translucent networks Transparent island Transparent networks
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Transparent networks
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Advanced all-optical switch networks (also called transparent networks) take advantage of the long transmission distance of an optical signal to transparently bypass intermediate switch nodes on the way of the signal traveling to its destination. The benefit of this kind of network falls into the simple node architecture at its intermediate switch nodes (no electronic switching fabrics need to be gone through thereby saving node cost) and the transparency of the data rate and protocol of optical channel. It is easy to carry out an upgradation for this kind of networks if a higher-rate network is necessary. However, this type of network shows the following drawbacks. First, since an optical signal suffers from various physical-layer impairments when it goes through an optical trail, the transmission distance of a lightpath is limited. For a large national network, no a completely transparent (without intermediate signal regeneration) lightpath is possible. Thus, a fully transparent optical network is impossible in wide-are national network. Second, since most lightpaths just transparently pass intermediate switch nodes, it is impossible for these nodes to look into the detail of the carried frames, thereby not possible for this type of network to perform an advanced lightpath performance monitoring. Such disability brings a challenge to the network control plane in the aspect of network fault detection and localization. Third, the feature of bypassing lightpath at intermediate nodes also disable subwavelength traffic grooming opportunity at these nodes, which may affect the capacity utilization of optical channels.
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Added: 29th July 2010 08:47:31 AM Modified: 29th July 2010 08:47:31 AM
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