Network Device Forwarding Rule Testing via Probe Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current network switch testing methods are inadequate for effectively testing forwarding rules, as traditional test probes are not designed to evaluate the forwarding behavior of network devices themselves, leading to inefficiencies, especially when routers are not functioning optimally.
Innovation Solution
A network device injects probe packets into its ingress pipeline, performing multiple layer 3 lookups to verify forwarding behavior, and redirects these probes to an external testing system for analysis, allowing for the determination of correct forwarding rules and behavior.
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 the paths and links in the network can be tested, but the forwarding rules of the network devices themselves cannot be tested
Solution Approach 1:
The patent introduces an intermediary testing mechanism where probe packets are injected into the ingress pipeline of the network device under test, and a testing system captures and analyzes these probes after they pass through the forwarding logic. This intermediary approach allows indirect observation of forwarding rule behavior without requiring direct access to internal device state, thereby enabling forwarding rule testing while maintaining system reliability.
Solution Approach 2:
The patent creates a copy of the normal data path by injecting probe packets that traverse the same ingress pipeline and forwarding logic as actual data traffic. These probe copies allow testing of forwarding rules without disrupting normal network operations, as the probes are processed alongside regular traffic but can be separately identified and analyzed by the testing system.
2Measurement precision
If multiple layer 3 lookups are performed on probe packets to verify forwarding behavior, then accurate routing can be determined, but the complexity of the testing process increases
Solution Approach 1:
The patent makes the network device's existing layer 3 lookup hardware serve multiple functions: it processes both normal data traffic and injected probe packets through the same forwarding logic. This multi-functionality allows accurate verification of forwarding behavior using the device's own routing infrastructure, avoiding the need for separate testing hardware or simplified test procedures that would compromise measurement precision.
3Reliability
If probe packets are injected into the ingress pipeline for testing forwarding rules, then comprehensive testing of network devices can be performed, but the network device complexity increases
Solution Approach 1:
The network device tests its own forwarding rules by injecting probe packets into its own ingress pipeline and processing them through its existing forwarding logic. This self-service approach eliminates the need for external testing equipment to replicate the device's forwarding behavior, thereby enabling comprehensive testing without adding external complexity to the network device structure.
Data Source
AI summary
A network device is described that injects probes for exercising its own forwarding rules (e.g., layer 2 and layer 3). One or more probe packets can be injected into an ingress pipeline of the network device using the agent executing on a local processor. The probes are detected before or after performing at least layer 2 and layer 3 lookups. Hardware in switching logic redirects the probes to an external testing system in order to verify the actual forwarding behavior applied to the probe packet. In order to deliver the probes to the external server, the network device performs an additional layer 3 lookup and generates an encapsulated packet incorporating results of a lookup on the probe packet. In this way, the external server can analyze the lookup on the probe packet to determine whether the lookup was performed correctly.