Router Reprogramming

  The router may be updated under program control. Each scheduled router is assumed to have a schedule memory which can hold multiple schedules (of which only one is active). Each location in the router in which a schedule can be placed has some index associated with it. New schedules can be downloaded to the router by specifying the desired index and providing the schedule information. COP requires a router schedule memory large enough to hold at least two complete schedules, so it can load a new schedule into the router while the previous one continues to run.

Similarly, each router is assumed to have multiple VFSMs, of which only some are used in a given schedule. VFSMs can be used for the same operator in multiple schedules (as is discussed in Section 5.1); however, VFSMs can also be reused by changing the source and destination annotations associated with the VFSM, then using the VFSM in a new schedule. An index is associated with each VFSM that allows it to be referenced both for scheduling and for reprogramming its annotations.