Virtual link aggregation using state machine

An aggregation switch comprising:

• a hardware network port to communicate with an access switch over a physical link between the access switch and the aggregation switch, the physical link to be aggregated with a physical link between the access switch and a remote aggregation switch within a virtual link aggregation group (vLAG) corresponding to a virtual link transparent to the access switch;
• a communication mechanism comprising one or more other hardware network ports to communicate with the remote aggregation switch to receive a status of the physical link between the access switch and the remote aggregation switch as one of up and down;
• and
• hardware to implement logic to maintain a state machine for the aggregation switch by which the aggregation switch is to assist in aggregation of the physical link between the access switch and the aggregation switch and the physical link between the aggregation access switch and the remote aggregation switch as the vLAG, by:
• where the physical link between the access switch and the local aggregation switch and the physical link between the access switch and the remote aggregation switch are down, and the vLAG is down, maintaining the state machine in an initialization state;
• where the physical link between the access switch and the local aggregation switch is up, the physical link between the access switch and the remote aggregation switch is down, and the vLAG is down, maintaining the state machine in the local-up state;
• where the physical link between the access switch and the remote aggregation switch is up, the physical link between the access switch and the local aggregation switch is down, and the vLAG is down, maintaining the state machine in the remote-up state;
• and
• where the physical link between the access switch and the local aggregation switch and the physical link between the access switch and the remote aggregation switch are up, and the vLAG is up, maintaining the state machine in the formed state.

A computer program product comprising:

• a non-transitory computer-readable storage medium having executable computer-readable code embodied therein that when executed by a processor causes the processor to:
• perform virtual link aggregation among physical links between an access switch and a pair of aggregation switches including a local aggregation switch and a remote aggre ag tion switch by maintaining a state machine;
• transition the state machine from an initialization state for a local aggregation switch to a local-up state in response to detecting that a physical link between an access switch and the local aggregation switch is up;
• transition the state machine from the initialization state to a formed state of the state machine in response to detecting that a physical link between the access switch and a remote aggregation switch is up;
• transition the state machine from the initialization state to a remote-up state of the state machine in response to detecting that the physical link between the access switch and the remote aggregation switch is up;
• and
• transition the state machine from the remote-up state to the formed state in response to detecting that the physical link between the access switch and the local aggregation switch is up,
• wherein a virtual link aggregation group (vLAG) aggregates the physical link between the access switch and the local aggregation switch and the physical link between the access switch and the remote aggregation switch into a virtual link transparent to the access switch.