Load balancing and overload control in a distributed processing telecommunications system

In a distributed multiprocessing telecommunications control system comprising a plurality of processors each for processing calls, a method of allocating new calls to ones of said plurality of processors comprising the steps of:

• receiving a measurement of real time work occupancy of each of said plurality of processors;
• responsive to said received measurements, adjusting an allocation of new calls to each processor to equalize the occupancies of each of said processors;
• detecting that an average of said measured occupancies of said processors exceeds a predetermined threshold;
• and
• shedding a fraction of new calls, said fraction determined to change an average occupancy of said processors to approximately equal said threshold.

In a distributed multiprocessing telecommunications control system comprising a plurality of processors each for processing calls, a method of allocating new calls to ones of said plurality of processors comprising the steps of:

• receiving a measurement of real time work occupancy of each of said plurality of processors;
• and
• responsive to said received measurements, adjusting an allocation of new calls to each processor to equalize the occupancies of each of said processors;
• wherein said adjusting is performed periodically and comprises adding to an allocated fraction for each processor for a prior period a predetermined multiple of a difference between an occupancy of said each processor during said prior period and an average occupancy of said plurality of processors during said prior period.

In a distributed multiprocessing telecommunications control system comprising a plurality of processors each for processing calls, a method of allocating new calls to ones of said plurality of processors comprising the steps of:

• receiving a measurement of real time work occupancy of each of said plurality of processors;
• and
• responsive to said received measurements, adjusting an allocation of new calls to each processor to equalize the occupancies of each of said processors;
• wherein said occupancy of each of said processors is measured periodically over the same period, and said adjusting is performed at a beginning of each period.

A method of assigning work to a plurality of processors comprising:

• determining a work occupancy for each of said processors;
• responsive to said occupancy determining, adjusting allocation fractions of new work for each of said processors toward work occupancy equalization among said processors;
• and
• thereafter allocating new work to said processors based on said adjusted allocation fractions.

In a distributed multiprocessing system comprising a plurality of processors each for performing data processing operations in response to requests, a method of allocating new requests to ones of said plurality of processors comprising the steps of:

• measuring a work occupancy of each of said plurality of processors;
• responsive to said measuring, periodically adjusting allocation fractions of new work requests for each processor toward work occupancy equalization among said processors;
• and
• thereafter, allocating new work to said processors based on said adjusted allocation fractions.

In a distributed multiprocessing telecommunications control system comprising a plurality of processors each for processing calls, a method of allocating new calls to ones of said plurality of processors comprising the steps of:

• measuring a work occupancy of each of said plurality of processors;
• periodically adjusting a fraction of new calls to be allocated to each processor in such manner that the occupancies of each of said plurality of processors are adjusted toward equalization;
• detecting that an average of said measured occupancies of said processors exceeds a predetermined threshold;
• and
• shedding a fraction of new calls, said fraction determined to attempt to achieve an average occupancy of said processors approximately equal to said threshold;
• wherein said shedding comprises adjusting said shed fraction by a multiple of a difference between a predetermined threshold value and a measured average occupancy of said plurality of processors;
• wherein said shed fraction is determined periodically by an algorithm:
• ##EQU5## wherein D.sub.1 represents said shed fraction for a next period, P.sub.0 represents a fraction of calls accepted during a period immediately prior to said next period, T represents a predefined constant representing an average occupancy of said plurality of processors at a threshold of overload of said telecommunications control system, A represents average measured occupancy of said plurality of processors during said prior period and G.sub.2 represents a predetermined gain factor;
• wherein said adjusting comprises adding to an allocated fraction for each processor for a prior period a predetermined multiple of a difference between an occupancy of said each processor during said prior period and an average occupancy of said plurality of processors during said prior period;
• wherein said allocated fraction for an i'th one of said plurality of processors is calculated by a formula:
• S.sub.1i =S.sub.0i +(A-a.sub.i)G.sub.1,
• wherein S.sub.1i, S.sub.0i represent an allocated fraction for said i'th processor for a next and said prior period, respectively, A represents an average occupancy of said plurality of processors during said prior period, a.sub.i represents an occupancy of said i'th processor during said prior period, and G.sub.1 represents a predetermined gain factor;
• and
• wherein said occupancy of each of said processors is measured periodically over the same period, and said adjusting is performed at a beginning of each period.