Automatic and Manual Channel Routing

  • Description

    The physical topology of the optical network may be quite complex. There can be several possible physical connections between a start node and an end node for some (or for all) traffic demands. The example discussed here involves the use of VPIlinkConfigurator GUI capabilities and external algorithms which perform automatic routing though the Application Programming Interface (API) of VPIlinkConfigurator.
    Figure 1 shows an example of network topology with the given logical connections or traffic demands (TDs). In this graphic, two types of TDs are displayed: green lines and brown lines, which correspond to routed and unrouted channels respectively.

  • Automatic Routing

    VPIlinkConfigurator (LC) offers several algorithms for automatic routing of primary channels: minimize channel length, minimize hop number along the channel route and minimize number of allocated wavelengths in the whole network. In addition, the API interface allows you to realize other sophisticated routing algorithms.

    A channel protection algorithm realized using the API of LC can be used to establish alternative channel routes once the traffic demands are routed. A protection channel is created if an alternative path for a route of a primary channel exists.

    Typical results of automatic channel routing and protection channel routing are shown in Figure 2 and Figure 3 respectively.

  • Manual Routing

    In some cases, the result of automatic channel routing does not correspond to the desired logical topology. For example, it is more important to have link load balancing rather than minimum number of allocated wavelengths. The topology editor in LC provides a simple graphic way to establish an alternative route manually for existing optical channels or for newly created logical connections. An example of manual channel routing is shown in Figure 4.

  • Creation of the Optical Segments

    In a network design containing many hops and long distances, OSNR considerations very often dictate the establishment of regeneration points in the middle of some traffic demands. In the Graph view, logical connections can be segmented to accommodate a regeneration point by simply using the Split Channel tool on individual channels or groups of channels, as shown in Figure 5.

  • Further Information

    Keywords: Optical Network Design, Traffic Demands, Channel Routing, Primary Channels, Protection Channels, Optical Segments, Regeneration Points, Application Programming Interface (API), Design Automation, Scripting

    Examples describing other steps of the design workflow are available in the WDM Network Design section.

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