US 6,983,294 B2
Redundancy systems and methods in communications systems
David Joseph Jones, Ottawa (Canada); and Douglas Heath Patriarche, Ottawa (Canada)
Assigned to Tropic Networks Inc., Kanata (Canada)
Filed on Apr. 12, 2002, as Appl. No. 10/120,435.
Claims priority of provisional application 60/289545, filed on May 09, 2001.
Prior Publication US 2002/0169794 A1, Nov. 14, 2002
Int. Cl. G06F 17/30 (2006.01)
U.S. Cl. 707—202 28 Claims
OG exemplary drawing
 
1. A redundancy method of managing requests in a control plane of a communication node, the communication node including a first control card and a second control card, the redundancy method comprising:
defining one of the control cards to be in an active state and the other of the control cards to be in an inactive state, the control card in the inactive state having a reduced set of privileges compared to the control card in the active state;
maintaining synchronicity of information stored on the control card in the active state and the control card in the inactive state such that the control card in the inactive state can assume responsibilities of the control card in the active state in case of failure of the control card in the active state;
monitoring for failure of the control card in the active state, and upon determining that a failure of the control card in the active state has occurred switching states of the control card in the inactive state and the control card in the active state such that the control card in the inactive state has the active state and the control card in the active state has the inactive state;
receiving or generating a request at the control card in the active state;
determining whether the request is to be passed to the control card in the inactive state; and
if the request is to be passed to the control card in the inactive state, passing the request to the control card in the inactive state.