Apparatus and method for preventing loops in a computer network

A network device configured to prevent the formation of loops in a computer network, the computer network organized into a spanning tree, the network device comprising:

• a port for interconnection to the computer network;
• a memory device associate with the port, the memory device configured to store a port state table, the port state table having a first data field to hold a role for the port, the role determined by a spanning tree protocol, the port state table having a second data field to hold a state for the port, the state selected by a user;
• and
• a processor configured to access the memory and compare the state selected by the user with the role determined by the spanning tree protocol, the processor further configured to set the port to a blocked port role if the role determined by the spanning tree protocol would cause the port to communicate down the spanning tree away from the root network device and the state selected by the user indicates the port is for communication up the spanning tree towards a root network device.

A network device configured to prevent the formation of loops in a computer network, the computer network organized into a spanning tree, the network device comprising:

• means for selecting a state for a port of the network device, the state indicating that the port is for communication up the spanning tree towards a root network device;
• means for executing a spanning tree protocol on the computer network, the spanning tree protocol determining a role for the port;
• means for comparing the state selected by the user with the role determined by the spanning tree protocol;
• and
• mean for setting the port to a blocked port role if the role for the port determined by the spanning tree protocol would cause the port to communicate down the spanning tree away from the root network device.

A method for preventing the formation of loops in a computer network, the computer network organized into a network topology by a link management protocol, the method comprising the steps of:

• selecting by a user a state for a port of the network device, the state indicating the port is for communication up the network topology toward a root network device;
• executing the link management protocol on the computer network, the link management protocol determining a role for the port;
• and
• comparing the state selected by the user with the role determined by the link management protocol, and if the role determined by the link management protocol would cause the port to communicate down the network topology away from the root network device, setting the port to a blocked port role.

A network device configured to prevent the formation of loops in a computer network, the computer network organized into a spanning tree, the network device comprising:

• a port for interconnection to the computer network;
• a memory device associate with the port, the memory device configured to store a port state table, the port state table having a first data field to hold a role for the port, the role determined by a link management protocol, the port state table having a second data field to hold a state for the port, the state selected by a user;
• and
• a processor configured to access the memory and compare the state selected by the user with the role determined by the link management protocol, the processor further configured to set the port to a blocked port role if the role determined by link management protocol would cause the port to communicate down a network topology away from the root network device and the state selected by the user indicates the port is for communication up the network topology toward a root network device.