Patent ID: 8194539

Claim:
A method for determining congestion in a communication system including a plurality of zone controllers logically connected by one or more paths in a packet switched network, the method comprising: at a zone controller: receiving a plurality of monitoring packets transmitted from-one other zone controller; monitoring transmission delay times for the plurality of monitoring packets; determining a first congestion level based on the transmission delay times; monitoring an amount of monitoring packets dropped for the plurality of monitoring packets; determining a second congestion level based on the amount of monitoring packets dropped; and determining a final congestion level based on the first congestion level and the second congestion level, whereby communications between the zone controller and the one other zone controller are controlled based on the final congestion level; upon determining that the final congestion level is indicative of heavy congestion, controlling communications between the zone controller and the one other zone controller using a first set of rules that includes at least one of (a) permitting transmission of a new call only if the new call is a high priority call (b) rejecting any follow-on push-to-talk requests for existing calls, and (c) terminating at least a portion of the existing calls; upon determining that the final congestion level is indicative of intermediate congestion, controlling communications between the zone controller and the one other zone controller using a second set of rules that includes at least one of (a) permitting transmission of a new call only if the new call is a high priority call, and (b) queuing a new call if the new call is not a high priority call; and upon determining that the final congestion level is indicative of light congestion, controlling communications between the zone controller and the one other zone controller using a third set of rules that includes providing a warning to a network manager that congestion has been identified.