Fast reroute between redundant multicast streams

• US 8,837,479 B1
• Filed: 06/27/2012
• Issued: 09/16/2014
• Est. Priority Date: 06/27/2012
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Kumar, Nitin, Sheth, Nischal, Konstantynowicz, Maciek, Ramachandran, Satish, Kebler, Robert
• Primary Examiner(s): Orgad, Edan
• Assistant Examiner(s): MAGLO, EMMANUEL K
• Application Number:
  US13/533,967
• Time in Patent Office: 811 Days
• Field of Search: 370/390, 370/395.31
• US Class Current: 370/390
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A packet-forwarding integrated circuit includes a control logic module and a selector block configured to produce a value indicating an incoming interface associated with a multicast data stream that meets stream health requirements, wherein the multicast data stream is one of a plurality of redundant multicast data streams each received on different incoming interfaces, wherein based on the value produced by the selector block the control logic module outputs data packets of the multicast data stream that meets stream health requirements received on the incoming interface, and discards data packets of other multicast data streams received on other incoming interfaces not indicated by the selector block. In response to detecting that a quality of one of the redundant multicast data streams has fallen below a configured threshold, the control logic automatically rewrites the selector block to forward a different one of the redundant multicast data streams.

Claims

1. A method comprising:

receiving, with a network device, a primary multicast stream and a secondary multicast stream, wherein the primary multicast stream and the secondary multicast stream are redundant multicast streams received over disjoint multicast forwarding paths;

applying a hardware-based analyzer in a forwarding plane of the network device to detect when a quality of the primary multicast stream has fallen below a threshold;

in response to detecting that the quality of the primary multicast stream has fallen below a threshold and the secondary multicast stream has a quality that meets the threshold and, with a hardware-based monitor block of the forwarding plane of the network device, reprogramming a hardware-based selector block of the forwarding plane to produce a value indicating that an incoming interface on which the secondary multicast stream is received is an expected incoming interface for the redundant multicast streams;

forwarding packets received on the secondary multicast stream in response to determining that the packets were received on the expected incoming interface output by the selector block; and

discarding packets of the primary multicast stream for which the quality has fallen below the threshold in response to determining that the packets of the primary multicast stream were not received on the expected incoming interface output by the selector block.

2. The method of claim 1, wherein the expected incoming interface comprises a reverse path forwarding (RPF) interface, further comprising:

upon receiving a packet, performing an RPF interface check for the entry based at least on the value, wherein the value indicates which of the incoming interfaces is the RPF interface for the entry, to determine whether an interface on which the packet is received is the same as the RPF interface.

3. The method of claim 1, further comprising:

programming a packet-forwarding integrated circuit in the forwarding plane of the network device to internally store a hardware version of a forwarding information base (FIB), the hardware version of the FIB including a plurality of entries addressable by the packet-forwarding integrated circuit, wherein at least one of the entries identifies a list of incoming interfaces of the network device, wherein the packet-forwarding integrated circuit comprises the selector block, wherein the selector block is configured to produce a value indicating which of the incoming interfaces of the list is an expected incoming interface on which packets matching the corresponding entry of the hardware version of the FIB are expected to be received,

wherein the selector block is configured to, in response to the control logic module addressing the one of the entries of the hardware version of the FIB, produce one of the incoming interfaces of the list associated with the addressed entry as the expected incoming interface for the entry based at least on the value produced by the selector block.

4. The method of claim 1, wherein applying the hardware-based analyzer comprises applying the hardware-based analyzer to analyze a quality of received packet streams on each of a plurality of incoming interfaces of the network device.

5. The method of claim 1, wherein applying the hardware-based analyzer comprises applying a hardware-based inverse policer in the forwarding plane detect that a packet flow rate of the primary multicast stream has dropped below a configured threshold packet flow rate.

6. The method of claim 1, further comprising:

storing, by the hardware-based analyzer, an indication of the quality of the received packet streams on each of the incoming interfaces; and

monitoring, by the hardware-based monitor block, the stored indication of the quality of the received packet streams.

7. The method of claim 3, wherein each of the entries of the hardware FIB is addressable by the packet-forwarding integrated circuit based on a multicast source address of received packets.

8. The method of claim 3, further comprising the selector block switching from producing an incoming interface associated with the primary multicast stream as the expected interface to producing the incoming interface associated with the secondary multicast stream as the expected interface, for those entries in the hardware version of the FIB that correspond to the selector block, without requiring the entries in the hardware version of the FIB to be individually rewritten.

9. The method of claim 3, wherein each of the entries of the hardware version of the FIB also identifies a forwarding next hop to which to forward received packets matching the respective entry, wherein the forwarding next hop comprises a list of outgoing interfaces to which to forward received packets.

10. A routing device comprising:

a forwarding component comprising;

a general-purpose processor; and

a packet-forwarding integrated circuit comprising;

a control logic module;

a hardware-based selector block configured to produce a value indicating an incoming interface associated with a multicast data stream that satisfies a quality threshold,

wherein the multicast data stream is one of a plurality of redundant multicast data streams each received on different incoming interfaces, wherein based on the value produced by the selector block the control logic module outputs data packets of the multicast data stream that meets stream health requirements received on the incoming interface, and discards data packets of other multicast data streams received on other incoming interfaces not indicated by the selector block;

a memory to store a hardware version of a forwarding information base (FIB), the hardware version of the FIB including a plurality of entries addressable by the packet-forwarding integrated circuit, wherein each of the entries is associated with different packet header key data, and identifies one or more forwarding next hops for forwarding data packets matching the respective entry, wherein each of the entries identifies a list of incoming interfaces of the network device and identifies the selector block to produce a value indicating which of the incoming interfaces of the list is an expected incoming interface on which packets matching the corresponding entry of the hardware version of the FIB are expected to be received,

wherein the selector block is configured to, in response to the control logic module addressing one of the entries of the hardware version of the FIB, produce one of the incoming interfaces of the list associated with the addressed entry as the expected incoming interface for the entry based at least on the value produced by the selector block; and

a hardware-based monitor block that, in response to detecting that a quality of one of the redundant multicast data streams received on the expected incoming interface has fallen below the quality threshold, automatically rewrites the associated selector block in the hardware version of the FIB to produce a value indicating that an incoming interface associated with a different one of the redundant multicast data streams is the expected incoming interface.

11. The routing device of claim 10, further comprising:

wherein the packet-forwarding integrated circuit forwards packets received on a primary multicast stream and discards packets received on a secondary multicast stream when the incoming interface of the routing device on which the primary multicast stream is received is the same as the expected interface produced by the selector block, and

wherein the monitor block, in response to detecting that a health of the primary multicast stream has fallen below a configured threshold, automatically rewrites the selector block in the hardware version of the FIB to produce a value indicating that an incoming interface associated with the secondary multicast stream is the expected incoming interface.

12. The routing device of claim 10 wherein the expected incoming interface comprises a reverse path forwarding (RPF) interface, wherein the control logic, upon receiving a packet, performs an RPF check for the entry based at least on the value indicating which of the incoming interfaces is the RPF interface for the entry.

13. The routing device of claim 10, wherein the packet-forwarding integrated circuit further comprises a plurality of hardware-based inverse policers to detect that a packet flow rate of the one of the redundant multicast streams has dropped below a configured threshold packet flow rate.

14. The routing device of claim 10, wherein each of the entries of the hardware version of the FIB also identifies a forwarding next hop to which to forward received packets.

15. The routing device of claim 10, wherein each of the entries of the hardware FIB is addressable by the packet-forwarding integrated circuit based on a multicast source address of received data packets.

16. A non-transitory computer-readable storage medium comprising instructions for causing a programmable processor to:

receive a primary multicast stream and a secondary multicast stream, wherein the primary multicast stream and the secondary multicast stream are redundant multicast streams received over disjoint multicast forwarding paths;

apply a hardware-based analyzer in a forwarding plane of the network device to detect when a quality of the primary multicast stream has fallen below a threshold;

in response to detecting that the quality of the primary multicast stream has fallen below a threshold the secondary multicast stream has a quality that meets the threshold, and, with a hardware-based monitor block of the forwarding plane of the network device, reprogram a hardware block of the forwarding plane to produce a value indicating that an incoming interface on which the secondary multicast stream is received is an expected incoming interface for the redundant multicast streams;

forward packets received on the secondary multicast stream in response to determining that the packets were received on the expected incoming interface output by the selector block; and

discard packets of the primary multicast stream for which the quality has fallen below the threshold in response to determining that the packets of the primary multicast stream were not received on the expected incoming interface output by the selector block.

17. A packet-forwarding integrated circuit comprising:

a hardware-based analyzer to detect when a quality of a primary multicast stream has fallen below a threshold, wherein the primary multicast stream and a secondary multicast stream are redundant multicast streams received over disjoint multicast forwarding paths; and

a hardware-based monitor block of the forwarding plane of the network device to, in response to detecting that the quality of the primary multicast stream has fallen below a threshold and the secondary multicast stream has a quality that meets the threshold reprogram a hardware block of the forwarding plane to produce a value indicating that an incoming interface on which the secondary multicast stream is received is an expected incoming interface for the redundant multicast streams,

wherein the packet-forwarding integrated circuit forwards packets received on the secondary multicast stream in response to determining that the packets were received on the expected incoming interface output by the selector block, and discards packets of the multicast stream received on the primary multicast stream for which the quality has fallen below the threshold in response to determining that the packets of the primary multicast stream were not received on the expected incoming interface output by the selector block.

18. A routing device comprising:

one or more interfaces to receive a primary multicast stream and a secondary multicast stream, wherein the primary multicast stream and the secondary multicast stream are redundant multicast streams received over disjoint multicast forwarding paths;

a forwarding component comprising;

a general-purpose processor; and

a packet-forwarding integrated circuit comprising;

a hardware-based analyzer to detect when a quality of the primary multicast stream has fallen below a threshold; and

a hardware-based monitor block of the forwarding plane of the network device to, in response to detecting that the quality of the primary multicast stream has fallen below a threshold and the secondary multicast stream has a quality that meets the threshold, reprogram a hardware block of the forwarding plane to produce a value indicating that an incoming interface on which the secondary multicast stream is received is an expected incoming interface for the redundant multicast streams;

wherein the packet-forwarding integrated circuit forwards packets received on the secondary multicast stream in response to determining that the packets were received on the expected incoming interface output by the selector block, and discards packets of the multicast stream received on the primary multicast stream for which the quality has fallen below the threshold in response to determining that the packets of the primary multicast stream were not received on the expected incoming interface output by the selector block.

19. The routing device of claim 18, wherein the forwarding component further comprises control logic that programs the packet-forwarding integrated circuit in the forwarding plane of the network device to internally store a hardware version of a forwarding information base (FIB), the hardware version of the FIB including a plurality of entries addressable by the packet-forwarding integrated circuit, wherein at least one of the entries identifies a list of incoming interfaces of the network device, wherein the packet-forwarding integrated circuit comprises the selector block, wherein the selector block is configured to produce a value indicating which of the incoming interfaces of the list is an expected incoming interface on which packets matching the corresponding entry of the hardware version of the FIB are expected to be received,

wherein the selector block is configured to, in response to the control logic module addressing the one of the entries of the hardware version of the FIB, produce one of the incoming interfaces of the list associated with the addressed entry as the expected incoming interface for the entry based at least on the value produced by the selector block.