| Summary: | 博士 === 國立中正大學 === 電機工程所 === 96 === In this thesis, the optical label-based packet switching schemes of optical transport network is presented. The optical label-based packet is labeled optical packet. The optical-label can bear the switching information. Labeled optical packet switching provides an efficient and speed-up forwarding mechanism of electronic IP packets over optical transport networks due to its single forwarding algorithm. Thus, it can produce low latency and enable scaling to terabit rates. We also proposed a label-based contention resolution method which conserves the cost and is easy to implement. This contention resolution scheme may also be used for making link protection. All-optical label switching is a promising approach of implementing fast switching techniques for transparent optical packet switching and forwarding in the optical layer at very high-speeds that are close to fiber line-rates.
Optical label switching has been proposed to simplify the packet forwarding process. The optical label is used to express routing information at an appropriate time. Using the label is simpler than the packet header to forward the packet so as to pass through the network. Therefore, a new labeling switching system is proposed. This method is to prefix an optical label to a packet, whose transmission requires neither label swapping nor O/E and E/O conversions. With this technique, the routing information is modulated in optical code format. Its basic idea is that as long as each passed node performs the correlation of the incoming optical label with certain specific codes in the optical domain without O/E conversion, then routing information to the next node can be resolved. This is a probable solution to avoid electronic bottlenecks in switching nodes. Thus, we used two correlator architectures to execute this idea. Our method doesn’t need any label swapping/header modification, so to the upper layer such as the label switching layer, the operation on optical networks is transparent. However, it still needs optical correlators to carry out the match of signals, instead of the address lookup.
On the other hand, we proposed an optical label-based forwarding with contention resolution scheme. This method has combined the technologies of source routing and label switching. It only uses the same label that provides the necessary switching information for each node point and also provides the deflection routing information that is needed when contention occurs. The contention resolution method that we have proposed is based on our proposed optical label switching scheme; we extend this optical label switching method such that solves packet contention automatically. A deflection routing is planning in advance at every core switching node which depends on the next forwarding node. If contention occurs among core switching nodes in the primary path, the packets will be locally detoured to the deflection next hop upon a contention detected as soon as possible.
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