Routing Networks in Multi-Leg Itineraries

An entire transportation network may be modeled as a single routing network, which is defined for the sole leg of a one-leg itinerary. However, routing networks may also be used in multi-leg itineraries, in which one or more of the legs of the itinerary have networks defined. One reason for setting up an itinerary this way is so that the routing network can be planned separately from the other legs of the itinerary.

Example of Routing Networks in Multi-Leg itineraries

In the following examples, you may want the planning in the routing networks to be separate from the planning of other itinerary legs:

• Land-Ocean-Land scenario: In this three-leg itinerary, the first and third legs are land legs each with its own routing network. The middle ocean leg has no routing network and represents a simple port-to-port voyage. In this scenario, planning land transportation on the first leg has nothing to do with planning land transportation on the third leg, so they can be planned separately.
• Multiple itineraries sharing a leg with a routing network: For example, a two-leg itinerary has an ocean leg and then a land leg with a routing network. Another itinerary has only the land leg with the routing network. For orders using the two-leg itinerary, the user may want to plan orders on the ocean leg without planning the land leg, because at this time the orders using the one-leg itinerary are not yet known, and the volume of these orders will determine the correct routes.

Note: If more than one itinerary is to share the same routing network, the itineraries should share the same itinerary leg with a routing network, rather than having different itinerary legs pointing to the same routing network.

In these cases, you can create an itinerary-leg-level order movement, and plan these in stages, as described in Network Routing and Order Movements.

Note: While both of these examples include an ocean leg, network routing and order movement planning do not support the Re-Use Equipment or Re-Use Service Provider parameters on legs.

Setup for Routing Networks in Multi-Leg itineraries

When a routing network is used in a multi-leg itinerary, the itinerary leg with the routing network may have a preceding or following itinerary leg. In either of these cases, the routing network needs to "connect" with the neighboring leg. The setup for this connection has to take into account the fact that an itinerary leg can define one or more destination locations, but not any source locations. For any itinerary but the first in a multi-leg itinerary, the source location(s) are defined by the previous itinerary leg's destinations. Because of this, a routing network in a multi-leg itinerary should be set up as follows:

• Routing Network Source Regions: If the itinerary leg with the routing network has a preceding leg, then the possible source locations for the routing network are the destination locations on the preceding itinerary leg. For this case, the source regions in the routing network should include these locations.
  
  For example, consider the case in the IL-OH network routing example where the routing network is the second leg of a two-leg itinerary, where the first itinerary leg is a rail leg, with possible destinations of Chicago and Mount Vernon. The source regions for Chicago and Mount Vernon on the routing network will allow the first leg to connect with the second leg routing network.
• Routing Network Destination Regions: If the itinerary leg with the routing network has a following leg, then the possible destination locations for the routing network are the destination locations on the itinerary leg with the routing network. For this case, the destination regions in the routing network should include these locations.
  
  For example, consider the case in the IL-OH network routing example where the routing network is the first leg of a two-leg itinerary, where the second itinerary leg is a rail leg. The rail hubs are Cleveland (in NE Ohio) and Cincinnati (in SW Ohio), and are defined as the destination locations of the itinerary leg with the routing network. In this case, the destination regions for NE Ohio and SW Ohio on the routing network will allow the first leg routing network to connect with the second leg.