Method and apparatus to control routing convergence during node reboot by entering a freeze state that inhibits routing convergence during the reboot process
First Claim
1. A method, comprising:
- transmitting, by a rebooting node before commencing a reboot process, a reboot notification message to specified nodes of a computer network having a routing topology represented by a directed acyclic graph (DAG), the reboot notification message indicating that the rebooting node of the DAG is unavailable during the reboot process, the reboot notification message further instructing the specified nodes to enter a DAG freeze state that inhibits routing convergence in the routing topology during the reboot process, the reboot notification message providing an identity of the rebooting node;
causing the specific nodes to receive traffic during the DAG freeze state, store the received traffic in a queue, monitor a length of the queue, and if the length of the queue exceeds a predetermined threshold, relay the reboot notification to other nodes of the routing topology; and
transmitting a clear message to the specified nodes upon completion of the reboot process, the clear message instructing the specified nodes to exit the DAG freeze state.
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Accused Products
Abstract
In one embodiment, a technique may enable control of routing convergence in a computer network during reboot of a node of a routing topology represented by a directed acyclic graph (DAG). The rebooting node, e.g., a DAG root node, may transmit a reboot notification message to nodes of the routing topology indicating that the rebooting node is unavailable during a subsequent reboot process. In response to receiving and processing the reboot notification message, the nodes of the routing topology may enter a DAG freeze state that inhibits (prevents) routing convergence in the routing topology during the reboot process so as prevent adverse consequences on network stability, such as collapse of the DAG. Thereafter upon completion of the reboot process, the rebooting node may transmit a clear message to the nodes of the routing topology that instructs the nodes to exit the DAG freeze state.
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Citations
20 Claims
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1. A method, comprising:
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transmitting, by a rebooting node before commencing a reboot process, a reboot notification message to specified nodes of a computer network having a routing topology represented by a directed acyclic graph (DAG), the reboot notification message indicating that the rebooting node of the DAG is unavailable during the reboot process, the reboot notification message further instructing the specified nodes to enter a DAG freeze state that inhibits routing convergence in the routing topology during the reboot process, the reboot notification message providing an identity of the rebooting node; causing the specific nodes to receive traffic during the DAG freeze state, store the received traffic in a queue, monitor a length of the queue, and if the length of the queue exceeds a predetermined threshold, relay the reboot notification to other nodes of the routing topology; and transmitting a clear message to the specified nodes upon completion of the reboot process, the clear message instructing the specified nodes to exit the DAG freeze state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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receiving a reboot notification message transmitted by a rebooting node of a computer network before commencing a reboot process, the computer network having a routing topology represented by a directed acyclic graph (DAG), the reboot notification message indicating that the rebooting node is unavailable during the reboot process; entering a DAG freeze state upon reception and processing of the reboot notification message, the DAG freeze state inhibiting routing convergence in the routing topology during the reboot process, the entering the DAG freeze state comprising receiving traffic during the DAG freeze state, storing the received traffic in a queue, monitoring a length of the queue, and if the length of the queue exceeds a predetermined threshold, relaying the reboot notification to other nodes of the routing topology; receiving a clear message transmitted by the rebooting node upon completion of the reboot process; and exiting the DAG freeze state in response to processing of the clear message. - View Dependent Claims (10, 11)
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12. An apparatus comprising:
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one or more network interfaces connected to a computer network having a routing topology represented by a directed acyclic graph (DAG); a processor coupled to the network interfaces and adapted to execute one or more processes; and a memory configured to store a process executable by the processor, the process when executed operable to; transmit, by a rebooting node before commencing a reboot process, a reboot notification message to specified nodes of the routing topology, the reboot notification message indicating that the rebooting node of the DAG is unavailable during the reboot process, the reboot notification message including a propagation flag configured to identify the specified nodes, the reboot notification message instructing the specified nodes to enter a DAG freeze state that inhibits routing convergence in the routing topology during the reboot process, the reboot notification message further providing an identity of the rebooting node; cause the specific nodes to receive traffic during the DAG freeze state, store the received traffic in a queue;
monitor a length of the queue, and if the length of the queue exceeds a predetermined threshold, relay the reboot notification to other nodes of the routing topology; andtransmit a clear message to the specified nodes upon completion of the reboot process, the clear message instructing the specified nodes to exit the DAG freeze state. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification