Supported Platforms
Offline Planning and Analysis
Despite the reduced management effort resulting from online path calculation, an offline planning and analysis tool is still required to optimize traffic engineering globally. Online calculation takes resource constraints into account and calculates one LSP at a time. The challenge with this approach is that it is not deterministic. The order in which LSPs are calculated plays a critical role in determining each LSP’s physical path across the network. LSPs that are calculated early in the process have more resources available to them than LSPs calculated later in the process because previously calculated LSPs consume network resources. If the order in which the LSPs are calculated is changed, the resulting set of physical paths for the LSPs also can change.
An offline planning and analysis tool simultaneously examines each link’s resource constraints and the requirements of each LSP. Although the offline approach can take several hours to complete, it performs global calculations, compares the results of each calculation, and then selects the best solution for the network as a whole. The output of the offline calculation is a set of LSPs that optimizes utilization of network resources. After the offline calculation is completed, the LSPs can be established in any order because each is installed according to the rules for the globally optimized solution.
