Abstract: In one embodiment, a packet switching device creates multiple virtual packet switching devices within the same physical packet switching device using virtual machines and sharing particular physical resources of the packet switching device. One embodiment uses this functionality to change the operating version (e.g., upgrade or downgrade) of the packet switching device by originally operating according to a first operating version, operating according to both a first and second operating version, and then ceasing operating according to the first operating version. Using such a technique, a packet switching device can be upgraded or downgraded while fully operating (e.g., without having to reboot line cards and route processing engines).

Abstract: In one embodiment, a packet switching device creates multiple virtual packet switching devices within the same physical packet switching device using virtual machines and sharing particular physical resources of the packet switching device. One embodiment uses this functionality to change the operating version (e.g., upgrade or downgrade) of the packet switching device by originally operating according to a first operating version, operating according to both a first and second operating version, and then ceasing operating according to the first operating version. Using such a technique, a packet switching device can be upgraded or downgraded while fully operating (e.g., without having to reboot line cards and route processing engines).

Abstract: In one embodiment, a packet switching device creates multiple virtual packet switching devices within the same physical packet switching device using virtual machines and sharing particular physical resources of the packet switching device. One embodiment uses this functionality to change the operating version (e.g., upgrade or downgrade) of the packet switching device by originally operating according to a first operating version, operating according to both a first and second operating version, and then ceasing operating according to the first operating version. Using such a technique, a packet switching device can be upgraded or downgraded while fully operating (e.g., without having to reboot line cards and route processing engines).

Abstract: In one embodiment, an operating system kernel and/or one or more processes of a high-availability system are modified while the system is operating and providing high-availability service. In accomplishing this, one embodiment uses a second virtual machine to operate a second operating system kernel including a second set of processes in the standby mode, which receive state information from corresponding process(es) in the active mode. Individually, the operating system kernel and processes within the second set of processes may be a same or different version of their counterpart in a first virtual machine and its processes which are being replaced. When the second set of processes have acquired sufficient state information to perform the standby role, the operation of the first virtual machine is typically ceased as the version modified second virtual machine is performing the version modified functionality of the first virtual machine.

Abstract: In one embodiment, an operating system kernel and/or one or more processes of a high-availability system are modified while the system is operating and providing high-availability service. In accomplishing this, one embodiment uses a second virtual machine to operate a second operating system kernel including a second set of processes in the standby mode, which receive state information from corresponding process(es) in the active mode. Individually, the operating system kernel and processes within the second set of processes may be a same or different version of their counterpart in a first virtual machine and its processes which are being replaced. When the second set of processes have acquired sufficient state information to perform the standby role, the operation of the first virtual machine is typically ceased as the version modified second virtual machine is performing the version modified functionality of the first virtual machine.

Abstract: In one embodiment, a packet switching device creates multiple virtual packet switching devices within the same physical packet switching device using virtual machines and sharing particular physical resources of the packet switching device. One embodiment uses this functionality to change the operating version (e.g., upgrade or downgrade) of the packet switching device by originally operating according to a first operating version, operating according to both a first and second operating version, and then ceasing operating according to the first operating version. Using such a technique, a packet switching device can be upgraded or downgraded while fully operating (e.g., without having to reboot line cards and route processing engines).