Network switching systems and methods

Patent metadata

Field	Value
Publication number	US-9800521-B2
Application number	US-201313975865-A
Country	US
Kind code	B2
Filing date	Aug 26, 2013
Priority date	Aug 26, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

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.

First claim

The invention claimed is:

1. An Ethernet protection switching system comprising:
a switching infrastructure residing at a line card within a network, the switching infrastructure operable to perform switching functions at the line card and comprising one or more of an ingress processor and an egress processor to process and distribute messages;
a central processing unit residing at the line card and communicatively coupled to the switching infrastructure, and configured to execute operations of a software module programmed to effectuate a first subset of potential control-plane actions for the network, in response to a set of events in the network and in accordance with a network protection protocol; and
protection hardware residing at the line card and communicatively coupled to the switching infrastructure and wired to effectuate a hardware-driven, control-plane change from a second subset of potential control-plane actions, in response to the set of events in the network based on the messages from the one of the ingress processor and the egress processor, in accordance with the network protection protocol, using logic circuitry operable at aggregate speeds quicker than those achievable by the software module, wherein the protection hardware uses its circuitry to determine the set of events independent of the software module by analysis of protection information to update the software module and to effectuate the hardware-driven, control-plane change separate from the software module,
wherein the first subset of potential control-plane actions is different from the second subset of potential control-plane actions, and
wherein the protection hardware is directly connected to the switching infrastructure via a dedicated communication pathway for the hardware-driven, control-plane change and is connected to the switching infrastructure and the central processing unit via a bus for the update to the software module.

2. The system of claim 1 , further comprising:
a port on the line card configurable to send and to receive a frame with a destination media-access-control address;
a set of internal registers within the switching infrastructure operable both to block and to unblock the port, the set of internal registers directly accessible by the protection hardware; and
a blocking module within the protection hardware wired to access the set of internal registers to block and to unblock the port in response to different events to effectuate the hardware-driven, control-plane change.

3. The system of claim 1 , further comprising a messaging module within the protection hardware wired to generate a message for distribution to the network by the switching infrastructure in response to an event to effectuate the hardware-driven, control-plane change in accordance with the network protection protocol.

4. The system of claim 1 , further comprising:
a switch database with learned entries, the switch database within the switching infrastructure used by the switching infrastructure to perform switching functions; and
a flushing module within the protection hardware in communication with the switch database and wired to flush a set of learned entries from the switch database in response to an event to effectuate the hardware-driven, control-plane change in accordance with the network protection protocol.

5. The system of claim 1 , wherein the protection hardware maintains a state variable consistent with the network protection protocol, and the protection hardware is wired to at least one of coordinate with the network and adapts the switching infrastructure in response to both a present state of the state variable and an event in the network to effectuate the hardware-driven, control-plane change consistent with the network protection protocol.

6. The system of claim 5 , further comprising a master state machine in the software module consistent with the network protection protocol, wherein the master state machine controls the state variable maintained in the protection hardware in a master/slave relationship and pushes a change of state at the master state machine to the state variable in the protection hardware.

7. The system of claim 5 , further comprising an administrator interface in the software module,
wherein the administrator interface is programmed to receive an operations-administration-and-maintenance command from a network administrator, and
the software module is programmed to change a present state of the master state machine in the software module in response to the operations-administration-and-maintenance command.

8. The system of claim 5 , further comprising a coordination module within the protection hardware, the coordination module wired to provide an update of an action taken by the protection hardware to the master state machine of the software module, wherein the software module amends a present state of the master state machine based on the update, in accordance with the network protection protocol.

9. The system of claim 1 , wherein the protection hardware is wired to at least one of coordinate with the network and adapts the switching infrastructure based on a role played by a link associated with the line card in the network protection protocol in response to an event to effectuate the hardware-driven, control-plane change.

10. The system of claim 1 , wherein the software module is programmed to respond to an event in the first set of events by sending a trigger to the protection hardware to facilitate a control-plane change in the network; and the protection hardware is wired to one of coordinate with the network and to adapt the switching infrastructure, after receiving the trigger from the software module to effectuate the hardware-driven, control-plane change.

11. The system of claim 1 , wherein the protecting switching functions are cooperatively performed by the protection hardware and the software module with the protection hardware configured to perform time-critical switching operations with the switching infrastructure and the software module configured to implement a state machine.

12. The system of claim 1 , wherein the protection hardware performs the second subset of potential control-plane actions directly with the switching infrastructure independent of the software module, and the protection hardware provides an update of the first subset of potential control-plane actions to the software module.

13. The system of claim 1 , wherein
the first subset of potential control-plane actions comprises implementation of a state machine and providing changes to state variables to the protection hardware, and reception of commands related to the state machine, and
the second subset of potential control-plane actions comprises blocking and unblocking ports, generation of messages to coordinate protection activities, and flushing switch database entries.

14. A method for protecting switching functions within a network, the method comprising:
provisioning network protection information to protection hardware residing within a line card in the network;
analyzing the protection information with circuitry in the protection hardware that is configured to determine a need for a control-plane change to protect the network;
responding to the need for the control-plane change with circuitry in the protection hardware wired to interface with switching infrastructure residing on the line card to alter the control plane of the network, wherein the protection hardware is configured to perform a second subset of potential control-plane actions; and
coordinating the control-plane change with a software module executed by a c

Assignees

• Ciena Corp

Inventors

• Holmberg Eric Arthur
• Nahlous Paul Simon
• Subramaniam Balaji

Classifications

• H04L45/22

  Alternate routing · CPC title

• H04L41/082

  the condition being updates or upgrades of network functionality · CPC title

• H04L49/557 Primary

  Error correction, e.g. fault recovery or fault tolerance · CPC title

• H04L12/437

  Ring fault isolation or reconfiguration {(for SDH/SONET ring networks H04J3/085)} · CPC title

• H04L49/351 Primary

  for local area network [LAN], e.g. Ethernet switches · CPC title