23.4.1.0.1 RouteLogic../ns-2/route-proto.tcl

This class defines two methods to configure unicast routing, and one method to query it for route information. It also defines an instance procedure that is applicable when the topology is dynamic. We discuss this last procedure in conjunction with the interface to network dynamics.

• The instance procedure []register../ns-2/route-proto.tclRouteLogic::register is invoked by []Simulator::rtproto. It takes the protocol and a list of nodes as arguments, and constructs an instance variable, rtprotos_, as an array; the array index is the name of the protocol, and the value is the list of nodes that will run this protocol.
• The []configure../ns-2/route-proto.tclRouteLogic::configure reads the rtprotos_ instance variable, and for each element in the array, invokes route protocol methods to perform the appropriate initializations. It is invoked by the simulator run procedure../ns-2/ns-lib.tclSimulator::run.

  For each protocol rt-proto indexed in the rtprotos_ array, this routine invokes Agent/rtProto/rt-proto init-all rtprotos_(rt-proto).

  If there are no elements in rtprotos_, the routine invokes Static routing, as Agent/rtProto/Static init-all.

• The instance procedure []lookup../ns-2/route-proto.tclRouteLogic::lookup takes two node numbers, nodeId₁ and nodeId₂, as argument; it returns the id of the neighbor node that nodeId₁ uses to reach nodeId₂.

  The procedure is used by the static route computation procedure to query the computed routes and populate the routes at each of the nodes. It is also used by the multicast routing protocols to perform the appropriate RPF check.

  Note that this procedure overloads an instproc-like of the same name. The procedure queries the appropriate rtObject entities if they exist (which they will if dynamic routing strategies are used in the simulation); otherwise, the procedure invokes the instproc-like to obtain the relevant information.