Techniques for uplink connectivity determination are disclosed. In an example, a Frame Link Module (FLM) in a frame, belonging to a group of frames connected in a ring network, may generate an uplink discovery packet. The FLM may determine, based on a Link Layer Discovery Protocol (LLDP) packet received by the standby uplink from a customer network accessing the ring that the standby uplink has a link to the customer network. The FLM may forward the uplink discovery packet to the standby uplink via a Peripheral Component Interconnect (PCI) interface. The FLM may send the uplink discovery packet to the customer network through the standby uplink directed to an owner FLM. The owner FLM may monitor receipt of the uplink discovery packet from the customer network through a current active uplink and on successful receipt may determine that the standby uplink and switches in the customer network are correctly configured.

In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.

Methods, systems, and computer programs are presented for managing a network in the presence of layer-2 loops. One method includes an operation for detecting, by a network device, a loop at a layer 2 of a network. The network device is configured to execute a network device operation system (ndOS), where network devices executing ndOS share a global switch table. The method further includes an operation for blocking ports associated with the loop where incoming packets received at the blocked ports are discarded except for loop-probe packets. Further, the method includes operations for sending loop-probe packets by one or more network devices executing ndOS through one or more ports, and for unblocking a first port of the blocked ports based on the loop-probe packets when a lack of receipt of a loop-probe packet within a predetermined amount of time is detected for the first blocked port which indicates that the first blocked port is not part of the loop.

Methods, systems, and computer programs are presented for managing a network in the presence of layer-2 loops. One method includes an operation for detecting, by a network device, a loop at a layer 2 of a network. The network device is configured to execute a network device operation system (ndOS), where network devices executing ndOS share a global switch table. The method further includes an operation for blocking ports associated with the loop where incoming packets received at the blocked ports are discarded except for loop-probe packets. Further, the method includes operations for sending loop-probe packets by one or more network devices executing ndOS through one or more ports, and for unblocking a first port of the blocked ports based on the loop-probe packets when a lack of receipt of a loop-probe packet within a predetermined amount of time is detected for the first blocked port which indicates that the first blocked port is not part of the loop.

In a connection-oriented network a point-to-multipoint working path is established between a source node and a plurality of destination nodes using a number of working path intermediate nodes. A point-to-multipoint protection path is established for possible points of failure in the working path. Each protection path connects a first working path intermediate node upstream of a point of failure and destination nodes of the working path downstream of the first working path intermediate node. The point-to-multipoint protection path only connects to destination nodes of the working path and working path intermediate nodes which must be transited to reach the destination nodes of the working path.

In a connection-oriented network a point-to-multipoint working path is established between a source node and a plurality of destination nodes using a number of working path intermediate nodes. A point-to-multipoint protection path is established for possible points of failure in the working path. Each protection path connects a first working path intermediate node upstream of a point of failure and destination nodes of the working path downstream of the first working path intermediate node. The point-to-multipoint protection path only connects to destination nodes of the working path and working path intermediate nodes which must be transited to reach the destination nodes of the working path.

A method and a device for realizing an optical channel data unit (ODU) shared protection ring (SPRing) are disclosed. The method includes: first, receive an ODUj, wherein the ODUj carries an ODUi; then, perform de-multiplexing processing to obtain the ODUi from the ODUj; next, multiplex the ODUi to an optical channel data unit k (ODUk); meanwhile, keep monitoring the ODUk; and when the monitoring result that is obtained through monitoring the ODUk indicates that a failure has occurred, perform a switching on the ODUi; wherein i, j, k are integers equal to or larger than 0, k is larger than j, j is larger than i, and i, j, k are used to indicate different rates of respective optical channel data unit (ODU) signals.

A method and a device for realizing an optical channel data unit (ODU) shared protection ring (SPRing) are disclosed. The method includes: first, receive an ODUj, wherein the ODUj carries an ODUi; then, perform de-multiplexing processing to obtain the ODUi from the ODUj; next, multiplex the ODUi to an optical channel data unit k (ODUk); meanwhile, keep monitoring the ODUk; and when the monitoring result that is obtained through monitoring the ODUk indicates that a failure has occurred, perform a switching on the ODUi; wherein i, j, k are integers equal to or larger than 0, k is larger than j, j is larger than i, and i, j, k are used to indicate different rates of respective optical channel data unit (ODU) signals.

Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.

Systems and methods are disclosed for providing redundancy in a network node implementing a ring protection protocol. Each of the two ring ports connecting the node to other nodes in a ring supporting the protocol may be maintained by a separate line card. Should one line card fail, traffic passing through the node may be redirected through the remaining ring port under the control of the surviving state machine. The two state machines may be coordinated over the backplane of the node to maintain a common state, making them transparent to other nodes. Additionally, the backplane link between the state machines may be monitored for failures that may be addressed with messages used to respond to general ring failures and by assigning one state machine to block a ring port upon recovery to prevent a loop within the ring until the ring protection link can be blocked.