The existing classes assume that the topology is static by default. In this section, we document the necessary changes to these classes to support dynamic topologies.
We have already described the instance procedures in the Simulator../ns-2/ns-lib.tcl to create or manipulate route models, , []rtmodel, []rtmodel-at, []rtmodel-delete, and []rtmodel-configure in earlier sectionsSectionsec:rtmodel. Similarly, the Node../ns-2/ns-node.tcl contains the instance procedure []intf-changed that we described in the previous sectionSectionsec:unicast-int.
The network dynamics code operates on individual links. Each model currently translates its specification into operations on the appropriate links. The following paragraphs describe the class Link and related classes.