On-path telemetry for multicast traffic
A per-hop postcard technique is disclosed. The per-hop postcard technique is implemented to improve Postcard-based Telemetry (PBT). A per-section postcard technique is also disclosed. The per-section postcard technique is implemented to improve In-situ OAM (IOAM). By utilizing these techniques, suitable on-path telemetry may be obtained for multicast traffic. In addition, these techniques may be used to reconstruct and visualize a multicast tree, to conduct performance monitoring, and to perform trouble shooting.
1. A method of collecting on-path telemetry data by a node in a multicast network, the method comprising:
receiving a multicast packet containing an instruction header;
collecting on-path telemetry data at the node as instructed by the instruction header;
determining whether the node is at an end of a section that extends between:
a root node and an adjacent branch node, or
adjacent branch nodes;
transmitting a postcard containing the on-path telemetry data collected by all nodes in the section to a controller only after determining the node is at the end of the section and before the multicast packet is replicated for transmission to a plurality of downstream leaf nodes; and
transmitting the instruction header and the on-path telemetry data collected by the node to a downstream node after determining the node is not at the end of the section.
2. The method of claim 1 , wherein the instruction header is appended to a multicast packet in accordance with an instruction received from a controller.
3. The method of claim 1 , wherein the instruction header is appended to a multicast packet when received.
4. The method of claim 1 , wherein the instruction header is appended to a multicast packet when transmitted.
5. The method of claim 1 , wherein the instruction header is received from an upstream node.
6. A method of collecting on-path telemetry data by a node in a multicast network, the method comprising:
receiving a multicast packet containing an instruction header;
collecting on-path telemetry data corresponding to the node as instructed by the instruction header;
transmitting a postcard to a collector as instructed by the instruction header, the postcard containing a branch identifier and only the on-path telemetry data corresponding to the node, the node comprising a branch node or a leaf node, the branch identifier comprising a node identifier (ID) and a branch index, the node ID and the branch index configured to provide the collector with a full data trace for an entire path when correlated with node IDs and branch indexes of other postcards; and
transmitting the instruction header to a downstream node.
7. The method of claim 6 , wherein the branch index identifies a branch from which the instruction header was received.
8. The method of claim 6 , wherein the branch index is an arbitrary number when the node is a root node.
9. The method of claim 6 , wherein the instruction header is appended to a multicast packet in accordance with an instruction received from a controller.
10. The method of claim 6 , wherein the instruction header is appended to a multicast packet when received.
11. The method of claim 6 , wherein the instruction header is appended to a multicast packet when transmitted.
12. The method of claim 6 , wherein the instruction header is received from an upstream node.
13. The method of claim 6 , wherein the node ID identifies the node when the node is a root node.
14. The method of claim 6 , wherein the node ID identifies an upstream node from which the instruction header was received when the node is a branch node or a leaf node.
15. The method of claim 6 , wherein the branch identifier is represented by a tuple with the format [node ID, index].
16. The method of claim 6 , wherein the branch index is utilized to construct a network topology.
17. A node configured to collect on-path telemetry data in a multicast network, the node comprising:
a receiver configured to receive a multicast packet containing an instruction header;
a processor coupled to the receiver, the processor executing instructions to cause the node to:
collect the on-path telemetry data at the node as instructed by the instruction header; and
determine whether the node is at an end of a section that extends between:
a root node and an adjacent branch node, or
adjacent branch nodes;
a transmitter coupled to the processor, the processor executing instructions to cause the node to, via the transmitter:
transmit a postcard to a collector only after determining the node is at the end of the section and before the multicast packet is replicated for transmission to a plurality of downstream leaf nodes; and
transmit the instruction header and the on-path telemetry data collected by the node to a downstream node after determining the node is not at the end of the section.
18. The node of claim 17 , wherein the instruction header is appended to a multicast packet in accordance with an instruction received from a controller.
19. The node of claim 17 , wherein the instruction header is appended to a multicast packet when received.
20. The node of claim 17 , wherein the instruction header is appended to a multicast packet when transmitted.
21. The node of claim 17 , wherein the instruction header is received from an upstream node.
22. The node of claim 17 , wherein the node comprises a receiver coupled to the processor, the receiver configured to receive an instruction from a controller, the instruction instructing the node to append the instruction header to a multicast packet.