Packet replication over chains of cascaded resilient link layer segments

1. A method comprising:

generating a switched link layer topology from a source device to a destination device, the switched link layer topology comprising a first sequence of switching devices, a second sequence of switching devices, and one or more bridging links between the first and second sequences of switching devices;

generating first and second chains of resilient link layer segments for respective first and second multi-hop link layer connections based on generating a sequence of link layer loops overlying the switched link layer topology via one or more of the bridging links, setting for the first multi-hop link layer connection a first set of connection blocks in the respective link layer loops, and setting for the second multi-hop link layer connection a corresponding second set of connection blocks in the respective link layer loops, the first set of connection blocks different from the second set of connection blocks; and

causing replication of a data packet across the first and second multi-hop link layer connections, enabling a failure in the switched link layer topology to be bypassed based on removing at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections, causing network traffic to utilize a modified resilient link layer segment between the first and second sequences of switching devices.

2. The method of claim 1 , wherein each of the first and second multi-hop link layer connections are distinct first and second virtual local area network (VLAN) connections having distinct VLAN identifiers, respectively, the causing replication including replicating the data packet across the first and second VLAN connections using the respective VLAN identifiers.

3. The method of claim 1 , further comprising:

detecting the failure in the switched link layer topology; and

causing the failure to be bypassed in the switched link layer topology based on sending an instruction causing the removal of at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections.

4. The method of claim 3 , further comprising:

detecting a second failure in the switched link layer topology; and

causing the second failure to be bypassed in the switched link layer topology based on sending a second instruction causing the removal of a second of the connection blocks for a second affected one of the first or second multi-hop link layer connections.

5. The method of claim 1 , wherein:

the generating of the first and second chains of resilient link layer segments includes initially setting the first set of the connection blocks associated with the first multi-hop link layer connection to block the first chain of resilient link layer segments from using the second sequence of switching devices, and initially setting the second set of the connection blocks associated with the second multi-hop link layer connection to block the second chain of resilient link layer segments from using the first sequence of switching devices, the second set of connection blocks initially set reciprocally to the first set of connection blocks;

wherein removal of one of the connection blocks for an affected portion of the first multi-hop link layer connection causes the first multi-hop link layer connection to bypass the failure in the first sequence of switching devices by utilizing a portion of the second sequence of switching devices.

6. The method of claim 1 , wherein:

the causing replication includes sending an instruction to a first replication/elimination device, configured for receiving the data packet from the source device, to initiate replication of the data packet toward ingress switching devices associated with the first and second multi-hop link layer connections;

the causing further including sending an instruction to a second replication/elimination device, configured for receiving the replicated data packets from egress switching devices associated with the first and second multi-hop link layer connections and further configured for forwarding a single copy of the data packet to the destination device, to forward to the destination device a single copy of the data packet.

7. The method of claim 1 , further comprising:

scheduling transmission of the data packet at selected switching devices based on the resilient link layer segments, including scheduling transmission in each resilient link layer segment to begin only after completed transmission in a corresponding successively preceding resilient link layer segment;

the causing replication executed in a selected one of the resilient link layer segments in response to the detected failure and corresponding removal of at least one of the connection blocks.

8. An apparatus comprising:

a processor circuit configured for generating a switched link layer topology from a source device to a destination device, the switched link layer topology comprising a first sequence of switching devices, a second sequence of switching devices, and one or more bridging links between the first and second sequences of switching devices;

the processor circuit further configured for generating first and second chains of resilient link layer segments for respective first and second multi-hop link layer connections based on generating a sequence of link layer loops overlying the switched link layer topology via one or more of the bridging links, setting for the first multi-hop link layer connection a first set of connection blocks in the respective link layer loops, and setting for the second multi-hop link layer connection a corresponding second set of connection blocks in the respective link layer loops, the first set of connection blocks different from the second set of connection blocks; and

a device interface circuit configured for causing replication of a data packet across the first and second multi-hop link layer connections, enabling a failure in the switched link layer topology to be bypassed based on removing at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections, causing network traffic to utilize a modified resilient link layer segment between the first and second sequences of switching devices.

9. The apparatus of claim 8 , wherein each of the first and second multi-hop link layer connections are distinct first and second virtual local area network (VLAN) connections having distinct VLAN identifiers, respectively, the causing replication including replicating the data packet across the first and second VLAN connections using the respective VLAN identifiers.

10. The apparatus of claim 8 , wherein the processor circuit is configured for:

detecting the failure in the switched link layer topology; and

causing the failure to be bypassed in the switched link layer topology based on sending an instruction causing the removal of at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections.

11. The apparatus of claim 10 , wherein the processor circuit is configured for:

detecting a second failure in the switched link layer topology; and

causing the second failure to be bypassed in the switched link layer topology based on sending a second instruction causing the removal of a second of the connection blocks for a second affected one of the first or second multi-hop link layer connections.

12. The apparatus of claim 8 , wherein:

the generating of the first and second chains of resilient link layer segments includes initially setting the first set of the connection blocks associated with the first multi-hop link layer connection to block the first chain of resilient link layer segments from using the second sequence of switching devices, and initially setting the second set of the connection blocks associated with the second multi-hop link layer connection to block the second chain of resilient link layer segments from using the first sequence of switching devices, the second set of connection blocks initially set reciprocally to the first set of connection blocks;

wherein removal of one of the connection blocks for an affected portion of the first multi-hop link layer connection causes the first multi-hop link layer connection to bypass the failure in the first sequence of switching devices by utilizing a portion of the second sequence of switching devices.

13. The apparatus of claim 8 , wherein:

the causing replication includes sending an instruction to a first replication/elimination device, configured for receiving the data packet from the source device, to initiate replication of the data packet toward ingress switching devices associated with the first and second multi-hop link layer connections;

the causing further including sending an instruction to a second replication/elimination device, configured for receiving the replicated data packets from egress switching devices associated with the first and second multi-hop link layer connections and further configured for forwarding a single copy of the data packet to the destination device, to forward to the destination device a single copy of the data packet.

14. The apparatus of claim 8 , wherein the processor circuit is configured for:

scheduling transmission of the data packet at selected switching devices based on the resilient link layer segments, including scheduling transmission in each resilient link layer segment to begin only after completed transmission in a corresponding successively preceding resilient link layer segment;

causing the replication to be executed in a selected one of the resilient link layer segments in response to the detected failure and corresponding removal of at least one of the connection blocks.

15. One or more non-transitory tangible media encoded with logic for execution by a machine and when executed by the machine operable for:

generating a switched link layer topology from a source device to a destination device, the switched link layer topology comprising a first sequence of switching devices, a second sequence of switching devices, and one or more bridging links between the first and second sequences of switching devices;

generating first and second chains of resilient link layer segments for respective first and second multi-hop link layer connections based on generating a sequence of link layer loops overlying the switched link layer topology via one or more of the bridging links, setting for the first multi-hop link layer connection a first set of connection blocks in the respective link layer loops, and setting for the second multi-hop link layer connection a corresponding second set of connection blocks in the respective link layer loops, the first set of connection blocks different from the second set of connection blocks; and

causing replication of a data packet across the first and second multi-hop link layer connections, enabling a failure in the switched link layer topology to be bypassed based on removing at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections, causing network traffic to utilize a modified resilient link layer segment between the first and second sequences of switching devices.

16. The one or more non-transitory tangible media of claim 15 , wherein each of the first and second multi-hop link layer connections are distinct first and second virtual local area network (VLAN) connections having distinct VLAN identifiers, respectively, the causing replication including replicating the data packet across the first and second VLAN connections using the respective VLAN identifiers.

17. The one or more non-transitory tangible media of claim 15 , further operable for:

detecting the failure in the switched link layer topology; and

causing the failure to be bypassed in the switched link layer topology based on sending an instruction causing the removal of at least one of the connection blocks for an affected one of the first or second multi-hop link layer connections.

18. The one or more non-transitory tangible media of claim 15 , wherein:

the generating of the first and second chains of resilient link layer segments includes initially setting the first set of the connection blocks associated with the first multi-hop link layer connection to block the first chain of resilient link layer segments from using the second sequence of switching devices, and initially setting the second set of the connection blocks associated with the second multi-hop link layer connection to block the second chain of resilient link layer segments from using the first sequence of switching devices, the second set of connection blocks initially set reciprocally to the first set of connection blocks;

wherein removal of one of the connection blocks for an affected portion of the first multi-hop link layer connection causes the first multi-hop link layer connection to bypass the failure in the first sequence of switching devices by utilizing a portion of the second sequence of switching devices.

19. The one or more non-transitory tangible media of claim 15 , wherein:

the causing replication includes sending an instruction to a first replication/elimination device, configured for receiving the data packet from the source device, to initiate replication of the data packet toward ingress switching devices associated with the first and second multi-hop link layer connections;

the causing further including sending an instruction to a second replication/elimination device, configured for receiving the replicated data packets from egress switching devices associated with the first and second multi-hop link layer connections and further configured for forwarding a single copy of the data packet to the destination device, to forward to the destination device a single copy of the data packet.

20. The one or more non-transitory tangible media of claim 15 , further operable for:

scheduling transmission of the data packet at selected switching devices based on the resilient link layer segments, including scheduling transmission in each resilient link layer segment to begin only after completed transmission in a corresponding successively preceding resilient link layer segment;

the causing replication executed in a selected one of the resilient link layer segments in response to the detected failure and corresponding removal of at least one of the connection blocks.