Scheme for label switched path loop detection at node device

A node device for transmitting packets to be label switched using an output label information capable of identifying a packet flow to be outputted, the node device comprising:

• a transmission unit configured to transmit a label allocation message requesting a set up of a label switched path that contain at least an information on said node device as an ingress node information regarding an ingress node of the label switched path;
• and
• a judging unit configured to judge that a label switched path loop is formed upon receiving a label allocation message in which the ingress node information specifies said node device as the ingress node.

A node device for label switching entered packets by referring to an input side label information capable of identifying a packet flow to be entered and a corresponding output label information capable of identifying the packet flow to be outputted, the node device comprising:

• an exchange unit configured to exchange with a neighboring node on a route of one packet flow a label allocation message requesting a set up of a label switched path which contains a flow ID capable of network globally identifying said one packet flow and an ingress node information regarding an ingress node of the label switched path;
• and
• a judging unit configured to judge whether a label switched path loop is formed or not, when a label allocation message that contains a flow ID and an ingress node information that are matching with an existing label switched path is received, according to a change in the input side label information for the existing label switched path.

A node device for label switching entered packets by referring to an input side label information capable of identifying a packet flow to be entered and corresponding one or a plurality of output label information capable of identifying the packet flow to be outputted, the node device comprising:

• an exchange unit configured to exchange with each one of a previous hop node and one or a plurality of next hop nodes on a route of one packet flow a label allocation message requesting a set up of a label switched path which contains an identifier for identifying said one packet flow and an ingress node information regarding an ingress node of the label switched path;
• and
• a judging unit configured to detect whether or not a message containing an identifier and an ingress node information that are identical to those of a previously exchanged message is received from a previous hop node different from one previous hop node from which the previously exchanged message is received, or whether or not a message that contains an identifier and an ingress node information that are identical to those of the previously exchanged message and changes the input side label information is received, and judge whether a label switched path loop is formed or not according to a result of detecting.

A node device for label switching entered packets by referring to one or a plurality of input side label information capable of identifying a packet flow to be entered and a corresponding output label information capable of identifying the packet flow to be outputted, the node device comprising:

• an exchange unit configured to exchange with a neighboring node on a route of one packet flow a message for setting up a new label switched path or utilizing an existing label switched path, which contains an identifier for identifying said one packet flow and an ingress node information regarding an ingress node of the new label switched path or the existing label switched path;
• and
• a judging unit configured to detect whether or not a message containing an identifier and an ingress node information that are identical to those of a previously exchanged message is received from a previous hop node device different from one previous hop node device from which the previously exchanged message is received, or whether or not a message that contains an identifier and an ingress node information that are identical to those of the previously exchanged message and changes the input side label information is received, and judge whether a label switched path loop is formed or not according to a result of detection.

A method of label switched path loop detection in a node device for label switching entered packets by referring to an input label information capable of identifying a packet flow to be entered and a corresponding information for specifying at least an output side interface, the method comprising the steps of:

• storing a flow ID capable of network globally identifying a packet flow and an ingress node information regarding an ingress node of a label switched path, according to one label allocation message requesting a set up of the label switched path which is received from one previous hop node;
• and
• judging whether a label switched path loop is formed or not according to from which node another label allocation message that contains an identical flow ID and an identical ingress node information as said one label allocation message is received.

A method of label switched path loop detection in a node device for transmitting packets to be label switched using an output label information capable of identifying a packet flow to be outputted, the method comprising the steps of:

• transmitting a label allocation message requesting a set up of a label switched path that contain at least an information on said node device as an ingress node information regarding an ingress node of the label switched path;
• and
• judging that a label switched path loop is formed upon receiving a label allocation message in which the ingress node information specifies said node device as the ingress node.

A method of label switched path loop detection in a node device for label switching entered packets by referring to an input side label information capable of identifying a packet flow to be entered and a corresponding output label information capable of identifying the packet flow to be outputted, the method comprising the steps of:

• exchanging with a neighboring node on a route of one packet flow a label allocation message requesting a set up of a label switched path which contains a flow ID capable of network globally identifying said one packet flow and an ingress node information regarding an ingress node of the label switched path;
• and
• judging whether a label switched path loop is formed or not, when a label allocation message that contains a flow ID and an ingress node information that are matching with an existing label switched path is received, according to a change in the input side label information for the existing label switched path.

A method of label switched path loop detection in a node device for label switching entered packets by referring to an input side label information capable of identifying a packet flow to be entered and corresponding one or a plurality of output label information capable of identifying the packet flow to be outputted, the method comprising the step of:

• exchanging with each one of a previous hop node and one or a plurality of next hop nodes on a route of one packet flow a label allocation message requesting a set up of a label switched path which contains an identifier for identifying said one packet flow and an ingress node information regarding an ingress node of the label switched path;
• and
• detecting whether or not a message containing an identifier and an ingress node information that are identical to those of a previously exchanged message is received from a previous hop node different from one previous hop node from which the previously exchanged message is received, or whether or not a message that contains an identifier and an ingress node information that are identical to those of the previously exchanged message and changes the input side label information is received, and judging whether a label switched path loop is formed or not according to a result of detecting.

A method of label switched path loop detection in a node device for label switching entered packets by referring to one or a plurality of input side label information capable of identifying a packet flow to be entered and a corresponding output label information capable of identifying the packet flow to be outputted, the method comprising the steps of:

• exchanging with a neighboring node on a route of one packet flow a message for setting up a new label switched path or utilizing an existing label switched path, which contains an identifier for identifying said one packet flow and an ingress node information regarding an ingress node of the new label switched path or the existing label switched path;
• and
• detecting whether or not a message containing an identifier and an ingress node information that are identical to those of a previously exchanged message is received from a previous hop node device different from one previous hop node device from which the previously exchanged message is received, or whether or not a message that contains an identifier and an ingress node information that are identical to those of the previously exchanged message and changes the input side label information is received, and judging whether a label switched path loop is formed or not according to a result of detecting.