Methods and systems for hitless switch management module failover and upgrade

A method for hitless switch management module failover, the method comprising:

• (a) at a first switch management module in a switch, operating in a master mode, wherein operating in the master mode includes:
• (j) performing packet forwarding and participating in network protocols;
• (ii) maintaining packet forwarding and protocol state information based on step (i) wherein maintaining packet forwarding information includes maintaining layer 2 spanning tree protocol information;
• and
• (iii) communicating the packet forwarding and protocol state information to a second switch management module operating in a slave mode;
• and
• (b) at the second switch management module in the switch, operating in the slave mode, wherein operating in the slave mode includes:
• (j) continuously monitoring the operational state of the first switch management module;
• (ii) receiving the packet forwarding and protocol state information from the first switch management module;
• and
• (iii) in response to detecting failure of the first switch management module, switching to the master mode and resuming network protocol operation from a state in which the first switch management module last operated correctly by injecting the received packet forwarding and protocol state information into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols.

A method for hitless switch management module failover, the method comprising:

• (a) at a first switch management module in a switch, operating in a master mode, wherein operating in the master mode includes:
• (k) performing packet forwarding and participating in network protocols;
• (ii) maintaining packet forwarding and protocol state information based on step (i);
• and
• (iii) communicating the packet forwarding and protocol state information to a second switch management module operating in a slave mode using a canonical message format, wherein the canonical message format is a message format that corresponds to message type and length rules stored by the master and slave switch management modules;
• and
• (b) at the second switch management module in the switch, operating in the slave mode, wherein operating in the slave mode includes:
• (k) continuously monitoring the operational state of the first switch management module;
• (ii) receiving the packet forwarding and protocol state information from the first switch management module;
• and
• (iii) in response to detecting failure of the first switch management module, switching to the master mode and resuming network protocol operation from a state in which the first switch management module last operated correctly based on the received packet forwarding and protocol state information.

A method for hitless switch management module failover, the method comprising:

• (a) at a first switch management module in a switch, operating in a master mode, wherein operating in the master mode includes:
• (i) performing packet forwarding and participating in network protocols;
• (ii) maintaining packet forwarding and protocol state information based on step (i);
• and
• (iii) communicating the packet forwarding and protocol state information to a second switch management module operating in a slave mode using bracketing to group related messages together, wherein using bracketing to group related messages together includes grouping all messages received between an open bracket and a closed bracket as part of a single transaction;
• and
• (b) at the second switch management module in the switch, operating in the slave mode, wherein operating in the slave mode includes:
• (i) continuously monitoring the operational state of the first switch management module;
• (ii) receiving the packet forwarding and protocol state information from the first switch management module;
• and
• (iii) in response to detecting failure of the first switch management module, switching to the master mode and resuming network protocol operation from a state in which the first switch management module last operated correctly based on the received packet forwarding and protocol state information.

A method for hitless switch management module failover, the method comprising:

• (a) at a first switch management module in a switch, operating in a master mode, wherein operating in the master mode includes:
• (j) performing packet forwarding and participating in network protocols;
• (ii) maintaining packet forwarding and protocol state information based on step (i);
• and
• (iii) communicating the packet forwarding and protocol state information to a second switch management module operating in a slave mode using bracketing to group related messages together, wherein using bracketing to group related messages together includes grouping all messages received between an open bracket and a closed bracket as part of a single transaction;
• and
• (b) at the second switch management module in the switch, operating in the slave mode, wherein operating in the slave mode includes:
• (i) continuously monitoring the operational state of the first switch management module;
• (ii) receiving the packet forwarding and protocol state information from the first switch management module;
• (iii) in response to detecting failure of the first switch management module, switching to the master mode and resuming network protocol operation from a state in which the first switch management module last operated correctly based on the received packet forwarding and protocol state information;
• and
• (iv) after switching to the master mode, detecting non-hitless operation and a cause for the non-hitless operation, and communicating the cause to the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version and storing the packet forwarding and protocol state information received from the first switch management module and operating the second switch management module without performing packet forwarding or participating in network protocols;
• (c) storing a second software version in memory;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory, wherein storing the second software version in memory associated with the second switch management module includes obtaining the second software version from a server and storing the second software version in memory associated with the second switch management module;
• (d) rebooting the second switch management module using the second software version;
• (f) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (g) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory;
• (d) rebooting the second switch management module using the second software version wherein rebooting the second switch management module includes performing a soft reboot of the second switch management module wherein software is reset, but hardware is not;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version using canonical messages, wherein the canonical message format is a message format that corresponds to message type and length rules stored by the master and slave switch management modules;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version using bracketing to group related message from the first switch management module to the second switch management module together in a single atomic transaction, wherein using bracketing to group related messages together includes grouping all messages received between an open bracket and a closed bracket as part of a single transaction;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory wherein the first software version is newer than the second software version;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A method for hitless software upgrade or downgrade in a switched network element, the method comprising:

• (a) operating a first switch management module in the switched network element in a master mode, wherein operating in the master mode includes forwarding packets and participating in network protocols using a first software version;
• (b) operating a second switch management module in a slave mode, wherein operating in the slave mode includes monitoring the operational state of the first switch management module using the first software version;
• (c) storing a second software version in memory wherein the first software version is older than the second software version;
• (d) rebooting the second switch management module using the second software version;
• (e) distributing protocol state and packet forwarding information from the first switch management module executing the first software version to the second switch management module executing the second software version;
• and
• (f) at the second switch management module, switching from operating in the slave mode to the master mode, wherein operating in the master mode includes injecting the protocol state and packet forwarding information received from the first switch management module into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols and starting packet forwarding and network protocol operations using the protocol state and packet forwarding information received from the first switch management module, thereby starting from the last correct network protocol operational state of the first switch management module.

A system for hitless switch management module failover, the system comprising:

• (a) a first switch management module for initially operating in a master mode, for managing the programming of hardware forwarding tables in a switched network element, for participating in network protocols, and for distributing protocol state, switch configuration, and packet forwarding information to a second switch management module;
• (b) a second switch management module for operating in a slave mode, for storing the packet forwarding, switch configuration, and protocol state information received from the first switch management module, for monitoring the operational state of the first switch management module, and for, in response to failure of the first switch management module, switching to operate in the master mode in a last correct network protocol operational state of the first switch management module by injecting the received protocol state and packet forwarding information into one or more subsystems of the second switch management module associated with performing packet forwarding and participating in network protocols;
• and
• (c) a user interface operatively associated with at least one of the first and second switch management modules for allowing a user to manually initiate a failover from the first switch management module to the second switch management module.