Patent ID: 6967955

Claim:
In an intermediate switch having a downstream trunk connected thereto via which other downstream switches are reachable, an upstream trunk connected thereto via which the intermediate switch can be reached by other upstream switches and a pre-provisioned set of virtual path identifiers exclusively available for use with connections on the downstream trunk between the downstream switches and either the intermediate switch or the upstream switches, a method of establishing a new connection between a target downstream switch and an upstream switch comprising the steps of: receiving a connection-establishment message from the upstream switch over the upstream trunk; determining whether one of the downstream switches is the target of the received connection-establishment message; and if one of the downstream switches is determined to be the target of the received connection-establishment message, performing the steps of: determining whether a connection to any of the downstream switches over which the intermediate switch is to receive data cells destined for the upstream switch already exists on the downstream trunk, such a connection being identified by a corresponding one of the pre-provisioned virtual path identifiers other than any of the pre-provisioned virtual path identifiers allocated for connection between the target downstream switch and the intermediate switch; if such a connection is determined to exist, sending a connection-establishment message over the downstream trunk, the message being addressed to the target switch and signaling a virtual path identifier previously allocated for use with the existing connection; and if no such connection is determined to exist, performing the steps of: allocating one of the pre-provisioned virtual path identifiers, other than any of the pre-provisioned virtual path identifiers allocated for connection between the target downstream switch and the intermediate switch, for use with a new connection over which the intermediate switch is to receive data cells from the downstream switches destined for the upstream switch; and sending a connection-establishment message, the connection-establishment message being addressed to the target switch and signaling the allocated virtual path identifier.