Network Switch Forwarding State Verification via Probe Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current network switch testing methods are inadequate for effectively evaluating the forwarding states of network devices, as traditional test probes are not designed to test the forwarding behaviors of network devices themselves, particularly in scenarios where routers may not be functioning optimally.
Innovation Solution
A deterministic model is introduced that uses lightweight agents to inject probe packets into the ingress pipeline of network devices, which perform layer 2 and layer 3 lookups, and include metadata or signatures to differentiate test probes from regular traffic, allowing for verification of forwarding behaviors by redirecting probes back to the control plane for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional test probes are sent from source host device through network switches to destination host device, then network paths and links can be tested, but forwarding states of network devices themselves cannot be tested
Solution Approach 1:
The patent introduces a test probe mechanism with metadata insertion as an intermediary between traditional end-to-end testing and actual forwarding state verification. The metadata acts as a marker that allows the system to track and verify forwarding decisions at each network device, enabling precise measurement of forwarding states without requiring changes to the overall test probe approach
Solution Approach 2:
The network device performs self-testing by injecting test probes into its own ingress pipeline and verifying the results through its control plane. This self-service capability allows the device to autonomously verify its forwarding states without external intervention, improving both reliability and measurement precision of forwarding behavior
2Reliability
If test probes include metadata or signatures for identification, then test probes can be differentiated from regular traffic, but device complexity increases
Solution Approach 1:
The patent applies local quality by implementing probe detection capability only at specific points in the data plane where needed, rather than throughout the entire device. The metadata insertion and detection is localized to the ingress pipeline and control plane interface, allowing the majority of the switching fabric to remain simple and high-performance while still enabling reliable probe identification
3Measurement precision
If network devices perform self-testing with probe injection and verification, then forwarding behavior can be verified, but processing overhead increases
Solution Approach 1:
The patent implements partial action by performing verification only on the metadata portion of the test probe rather than analyzing the entire packet. The control plane verifies that the metadata was correctly inserted and that the forwarding decision matches expectations, without needing to process the complete packet payload, thus reducing processing overhead while maintaining verification accuracy
Data Source
AI summary
A deterministic model is described that is used for testing networks by exercising forwarding rules (e.g., layer 2 and layer 3) on network devices. Within a single network hop, a light-weight agent can be used to control the testing. One or more probe packets can be injected into an ingress pipeline of a network device using the agent executing on a local processor. The probes are detected after performing at least layer 2 and layer 3 lookups. Hardware in switching logic redirects the probes to the local processor in order to verify the actual forwarding behavior applied on the probe packet.