NAME

       bpclock - Bundle Protocol (BP) daemon task for managing scheduled events

SYNOPSIS

       bpclock

DESCRIPTION

       bpclock is a background "daemon" task that periodically performs scheduled Bundle Protocol
       activities.  It is spawned automatically by bpadmin in response to the 's' command that
       starts operation of Bundle Protocol on the local ION node, and it is terminated by bpadmin
       in response to an 'x' (STOP) command.

       Once per second, bpclock takes the following action:

           First it (a) destroys all bundles whose TTLs have expired, (b) enqueues for re-
           forwarding all bundles that were expected to have been transmitted (by convergence-
           layer output tasks) by now but are still stuck in their assigned transmission queues,
           and (c) enqueues for re-forwarding all bundles for which custody has not yet been
           taken that were expected to have been received and acknowledged by now (as noted by
           invocation of the bpMemo() function by some convergence-layer adapter that had CL-
           specific insight into the appropriate interval to wait for custody acceptance).

           Then bpclock adjusts the transmission and reception "throttles" that control rates of
           LTP transmission to and reception from neighboring nodes, in response to data rate
           changes as noted in the RFX database by rfxclock.

           bpclock then checks for bundle origination activity that has been blocked due to
           insufficient allocated space for BP traffic in the ION data store: if space for bundle
           origination is now available, bpclock gives the bundle production throttle semaphore
           to unblock that activity.

           Finally, bpclock applies rate control to all convergence-layer protocol inducts and
           outducts:

               For each induct, bpclock increases the current capacity of the duct by the
               applicable nominal data reception rate.  If the revised current capacity is
               greater than zero, bpclock gives the throttle's semaphore to unblock data
               acquisition (which correspondingly reduces the current capacity of the duct) by
               the associated convergence layer input task.

               For each outduct, bpclock increases the current capacity of the duct by the
               applicable nominal data transmission rate.  If the revised current capacity is
               greater than zero, bpclock gives the throttle's semaphore to unblock data
               transmission (which correspondingly reduces the current capacity of the duct) by
               the associated convergence layer output task.

EXIT STATUS

       "0" bpclock terminated, for reasons noted in the ion.log file.  If this termination was
           not commanded, investigate and solve the problem identified in the log file and use
           bpadmin to restart bpclock.

       "1" bpclock was unable to attach to Bundle Protocol operations, probably because bpadmin
           has not yet been run.

FILES

       No configuration files are needed.

ENVIRONMENT

       No environment variables apply.

DIAGNOSTICS

       The following diagnostics may be issued to the ion.log log file:

       bpclock can't attach to BP.
           bpadmin has not yet initialized BP operations.

       Can't dispatch events.
           An unrecoverable database error was encountered.  bpclock terminates.

       Can't adjust throttles.
           An unrecoverable database error was encountered.  bpclock terminates.

BUGS

       Report bugs to <ion-bugs@korgano.eecs.ohiou.edu>

SEE ALSO

       bpadmin(1), rfxclock(1)