Transmitting packet label contexts within computer networks

摘要

In general, techniques are described for transmitting context information defining contexts for packet labels in a network. More specifically, a network device, e.g., a router, implements the context transmission techniques to facilitate debugging or troubleshooting of the network. The network device may comprise an interface card that receives a Multi-Protocol Label Switching (MPLS) data unit from another network device in accordance with a label switching protocol. The data unit may include a label stack affixed to a payload. The label stack may include one or more MPLS labels and context information associated with at least one of these labels, The interface card may, when forwarding the data unit, parse the data unit to determine the context information and then forward the data unit in accordance with these MPLS labels. A control unit included within the network device may record the forwarding of the data unit and the determined context information.

主权项

1. A method comprising:
receiving, with a first network device intermediately positioned along a label-switched path (LSP) through a network between an ingress to the LSP and an egress to the LSP, a Multi-Protocol Label Switching (MPLS) data unit from a second network device of the network in accordance with a label switching protocol, wherein the data unit includes a label stack affixed to a payload, wherein the label stack includes two or more MPLS labels used for forwarding the data unit through the network and context information associated with at least two of the MPLS labels of the label stack, wherein the context information is arranged in the label stack to alternate between entries containing individual ones of the two or more MPLS labels and entries containing portions of the context information that pertains to the preceding one of the MPLS labels in the label stack and provides a context unused to forward the MPLS data unit and for understanding the associated at least two MPLS labels of the label stack, and wherein the context information identifies a packet flow transported by the data unit by specifying a source address, a source port, a destination address, a destination port and a protocol associated with the payload contained within the data unit; forwarding the data unit out an output interface of the first network device in accordance with the two or more MPLS labels of the label stack; when forwarding the data unit, parsing, with the first network device, the data unit to determine the context information; and recording, with the first network device, the forwarding of the data unit and the determined context information.