Method and apparatus for providing an uplink over an access ring
A method for providing an uplink over an access ring comprising access devices and at least one aggregation device, wherein each device of said access ring has ring interfaces connecting said device to neighboring devices in said access ring, wherein one access device of said access ring is configured as a ring master device which sends connectivity check messages on both its ring interfaces around said access ring to itself to detect a connectivity failure in said access ring, and wherein said ring master device changes a state of one of its ring interfaces depending on the detection result.
1. A method for providing an uplink over an access ring comprising access devices and at least one aggregation device,
wherein each device of said access ring has ring interfaces connecting said device to neighbouring devices in said access ring,
wherein one access device of said access ring is configured as a ring master device which sends connectivity check messages on both its ring interfaces around said access ring to itself to detect a connectivity failure in said access ring,
wherein said ring master device changes a state of one of its ring interfaces depending on the detection result;
the method comprising:
transporting connectivity check messages around said access ring via a connectivity check message control Virtual Local Area Network (VLAN) provided between aggregation devices of said at least one aggregation device; and
sending by the ring master device of said access ring a spanning tree topology change notification via the connectivity check message control VLAN on both of its ring interfaces upon each change of a state of one of its ring interfaces performed in response to a detection result.
2. The method according to claim 1 ,
wherein said ring master device opens one of its ring interfaces having been blocked for data traffic for avoidance of a closed loop in said access ring to restore a connectivity in said access ring if a connectivity failure is detected by said ring master device.
3. The method according to claim 1 ,
wherein said ring master device sends the connectivity check messages at a constant rate with an adaptable default interval between two consecutive connectivity check messages.
4. The method according to claim 1 ,
wherein a connectivity failure in said access ring is detected by the ring master device of said access ring if the ring master device does not receive a predetermined number of connectivity check messages at both its ring interfaces for a predetermined time.
5. The method according to claim 1 ,
wherein said ring master device blocks one of its ring interfaces if it receives a connectivity check message on either of its ring interfaces.
6. The method according to claim 1 ,
wherein a maintenance end point is assigned to each ring interface of said ring master device.
7. The method according to claim 1 ,
wherein the devices of said access ring are formed by Ethernet devices.
8. A ring master device comprising:
ring interfaces connecting said ring master device to neighbouring devices of an access ring,
wherein said ring master device is configured to send, using a controller, connectivity check messages on both its ring interfaces around said access ring to itself to detect a connectivity failure in said access ring and to change the state of one of its ring interfaces depending on the detection result;
wherein connectivity check messages are transported around said access ring via a connectivity check message control Virtual Local Area Network (VLAN) provided between aggregation devices of at least one aggregation device, and
wherein the ring master device of said access ring sends a spanning tree topology change notification via the connectivity check message control VLAN on both of its ring interfaces upon each change of a state of one of its ring interfaces performed in response to a detection result.
9. An access ring comprising:
a ring master device according to claim 8 ,
access devices each having at least one client interface for connecting a terminal device to said access ring and comprising:
at least one aggregation device adapted to connect said access ring to a network core.
10. The access ring according to claim 9 ,
wherein said aggregation device is an aggregation switch device adapted to connect said access ring with said network core.
11. The access ring according to claim 9 ,
wherein an access device being positioned farthest from said network core in said access ring is configured as the ring master device of said access ring.
12. The access ring according to claim 9 , wherein the devices of said access ring are Ethernet devices being connected to each other by interfaces transporting Ethernet packets.
13. The access ring according to claim 12 ,
wherein said Ethernet packets are transported between said Ethernet devices through an optical or electrical transport medium.