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)