Abstract: Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

Abstract: Systems and methods are disclosed for effectuating control-plane changes at increased speeds to protect a network in which switching operations are performed. Operations to effectuate control-plane changes in the network can be divided between software and more-rapid, dedicated hardware within a line card. Examples of operations reserved to hardware implementation can include blocking and unblocking of ports, flushing of learned entries from switch tables, and coordination of control-plane changes through the generation of messages sent between nodes, and also between line cards of a node. Determinations about the need for hardware-driven, control-plane changes may be made based on events occurring in the network in accordance with any of a number of different network protection protocols. The protocol may be implemented in a state machine and the software may determine the state of the hardware through a master/slave relationship.

Abstract: Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

Abstract: Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

Abstract: Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

Abstract: Systems and methods are disclosed for effectuating control-plane changes at increased speeds to protect a network in which switching operations are performed. Operations to effectuate control-plane changes in the network can be divided between software and more-rapid, dedicated hardware within a line card. Examples of operations reserved to hardware implementation can include blocking and unblocking of ports, flushing of learned entries from switch tables, and coordination of control-plane changes through the generation of messages sent between nodes, and also between line cards of a node. Determinations about the need for hardware-driven, control-plane changes may be made based on events occurring in the network in accordance with any of a number of different network protection protocols. The protocol may be implemented in a state machine and the software may determine the state of the hardware through a master/slave relationship.