DISCUSSIONS & CONCLUSIONS
This work mainly consists of top-down investigations of the benefits of optical layer services and the requirements for the optical layer. A reconfigurable optical network provides faster user connectivity over the optical network. Automation of such provisioning can be done ultimately where user's equipment in optical network environment. It can be noted that inter-working between layers (represented by optical and user's equipment in this case) also makes use of the bottom-up approach since the upper layer(s) need to be enhanced with new functionality.
The optical network is reconfigured and N X N connectivity is achieved by using fiber span layout demand distribution in this work. In view of the above there is no need for installation, removal and replacement of existing network elements. The optical layer has the advantage of faster protection/restoration. As failure recovery may take place in several layer networks (when several user layers reside on the optical layer), a well-defined strategy is implemented to avoid competing and conflicting recovery processes.
Physical Layer represents the network connectivity by means of guided media. It represents single node to multiple node connectivity. It also establishes the physical path between transmitter and receiver via transmission media. Four algorithms have been proposed with respect to the fiber span layout and its demand distribution, fiber network user service survivability, optical network demand bundling using digital signal forming and synchronous optical networks.
- The first one describes the traffic connectivity distribution among the network connectivity.
- The second one can handle both cable cuts and switching equipment failures at a faster rate without relying on central manager and centralized database.
- A third represents different types of demands that can be met by using direct and indirect methods.
- Finally an integrated approach for survivability planning period is proposed.
Logical Layer represents the network connectivity by means of unguided media. It represents multiple node to multiple node connectivity. It also establishes the logical path between transmitter and receiver via transmission media.
As compared to physical layer discussed so far, three more algorithms were developed. They are (i) Two-Tier, (ii) BFMLM-FQ and (iii) Hybrid fair packet scheduling algorithm.
- In Two-Tier algorithm, the parameters are designed, developed and the global topology independent fairness model is achieved. Multilayered network topology enhancement is worked out by using the parameters like multiflows and packet level transformations in a global network.
- In BFMLM-FQ algorithm, the node mobility and scalability is implemented. It also provides the maximum channel reutilization by using the parameters like fair distribution of bandwidth, packet delivery and throughput.
- In the hybrid fair packet scheduling algorithm location dependent, location- independent mechanisms and spatial locality are achieved by max-min fair queuing method.
- Finally, the planning and designing of survivable optic networks integrates the physical layer model and the logical layer model as computed from various simulated models. Correlation of these results corroborates the validity of the algorithms more effectively.
Scope for Future Work:
Any future work may extend to the study of many of the various possible areas, a few of which are listed here.
- A study of wavelength services to evaluate the bulk carriers in optical network survivability which may lead to optical cross connectivity.
- Local restoration methodology.
- Transition from ring to ring-mesh hybrid.
- Convergence of the distributed algorithm such as asynchronous computation and stochastic approximation.
- To study the survivable optical tradeoffs & associated network growth strategies.
- The generalization of time-optimal control to multiple congested nodes.
- Utilization of Price-based approach in ad-hoc networks.
- Refinement of the routing protocols for ad hoc networks.
- Optical virtual private networks in ad-hoc networks.