Method and device for operating a network and communication system comprising such device
A method and a device are provided for operating a network, wherein the network comprises several network elements that are connected via a ring, wherein a first segment is of a first type of connection and wherein a second segment is of a second type of connection, wherein the ring comprises at least one first segment and at least one second segment and wherein one network element of the network elements is a ring master comprising a primary port and a secondary port, comprising the steps (i) a failure of at least one of the at least one first segment is detected by the ring master; (ii) the ring master unblocks its secondary port; and (iii) the ring master sends a first message via its primary port and via its secondary port.
1. A method of operating a network, which comprises:
providing the network with:
a plurality of network elements connected via a ring;
wherein a first segment comprises a non-Ethernet connection and a second segment is an Ethernet connection;
the ring including at least one first segment and at least one second segment; wherein one network element of the network elements is a ring master having a primary port and a secondary port;
wherein a network element of the at least one second segment runs an Ethernet ring protection mechanism using test packets;
the method which comprises the following steps:
detecting a failure of at least one of the at least one first segment by the ring master;
unblocking the secondary port of the ring master;
sending a first message by the ring master via the primary port and via the secondary port;
responding, with each network element that received the first message, with an acknowledge message and forwarding the first message to a next network element; if a network element does not receive an acknowledge message, entering a pre-forwarding state with the network element, the pre-forwarding state being a state in which the network element blocks all traffic except the test packets and waits to switch over to normal operation;
in the pre-forwarding state, blocking a port of the network element toward the network element that did not send the acknowledge message;
sending a second message to the ring master with the network element entering the pre-forwarding state;
after recovery of the failure, blocking the secondary port of the ring master and sending a third message via the primary port and via the secondary port; and
upon receiving the third message, switching each network element residing in the pre-forwarding state to the normal operation.
2. The method according to claim 1 , wherein the second message is a message informing about a network element having entered the pre-forwarding state.
3. The method according to claim 1 , wherein the first message is a pre-forwarding state request.
4. The method according to claim 1 , which comprises sending the first message via a protocol that addresses a network element that is directly connected to the sending network element.
5. The method according to claim 1 , which comprises sending the first message via a slow protocol.
6. The method according to claim 1 , wherein the non-Ethernet connection comprises at least one of the following connections:
a wave division multiplexing connection; and
a dense wave division multiplexing connection.
7. The method according to claim 1 , wherein the Ethernet ring protection mechanism comprises at least one of the following:
an Ethernet Ring Protection (ERP) protocol;
an Ethernet Automatic Protection Switching (EAPS) protocol.
8. The method according to claim 1 , which comprises running the method repeatedly.
9. The method according to claim 1 , which comprises sending the test packets by the ring master via the primary port and via the secondary port thereof.
10. The method according to claim 9 , which comprises sending the test packets via a control virtual LAN.
11. A device of a network, comprising a processor unit arranged and configured to execute the steps of the method according of claim 1 on said processor.
12. The device according to claim 11 , wherein said device is a communication device.
13. The device according to claim 11 , wherein said device is a network element.
14. A communication system, comprising the device according to claim 11 .