Synthetic Packet Forwarding Decision Retrieval
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Solution Overview
Problem
Current methods for diagnosing network path problems in packet-switched networks are inadequate as they fail to provide detailed information about forwarding decisions, especially in routers using Policy-Based Routing (PBR) and Multi-Topology Routing (MTR), and pose security risks due to processing of IP source routing options being disabled.
Innovation Solution
The implementation of a system that uses synthetic packets and API logic to retrieve forwarding information by generating packets with 'debug' flags, allowing detailed recording of forwarding decisions across multiple network layers without security concerns, including PBR and MTR configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If ICMP-based mechanisms are used to trace network paths, then path tracing capability is provided, but detailed forwarding decision information from PBR and MTR cannot be obtained
Solution Approach 1:
The patent introduces synthetic packets as an intermediary mechanism to obtain forwarding decisions. These synthetic packets are generated by a network element and processed through the forwarding logic to capture detailed decision information without requiring external ICMP messages or source routing options, thus bridging the information gap while maintaining security.
Solution Approach 2:
The patent creates synthetic packets that copy the essential characteristics of real data packets (including PBR and MTR relevant fields) to probe the forwarding logic. By copying packet structures and processing them through the same forwarding path, the system obtains accurate forwarding decision information without using traditional diagnostic methods that lack detail.
2Loss of information
If IP source routing option is used to diagnose network paths, then path information can be obtained, but security risks arise causing processing to be disabled in most routers
Solution Approach 1:
The patent uses synthetic packets generated internally by the network element as an intermediary to obtain path diagnostic information. This eliminates the need for external source routing options that pose security risks, as the synthetic packets are created and controlled by the network element itself, removing the security vulnerability while maintaining diagnostic capability.
Solution Approach 2:
The network element performs self-diagnosis by generating its own synthetic packets and processing them through its forwarding logic. This self-service approach eliminates dependency on external diagnostic mechanisms like source routing, allowing the router to obtain path information securely without exposing itself to security risks from external packet manipulation.
3Measurement precision
If traditional ICMP or source routing approaches are used, then basic path tracing is possible, but detailed forwarding decisions across multiple protocol layers cannot be captured
Solution Approach 1:
The patent creates a universal synthetic packet mechanism that can capture forwarding decisions across multiple protocol layers (network layer, transport layer, application layer) through a single integrated approach. The synthetic packets are designed to include fields relevant to PBR and MTR, allowing one system to perform multiple diagnostic functions that would otherwise require separate complex mechanisms for each protocol layer.
Data Source
AI summary
In one embodiment, an apparatus comprises one or more forwarding logic components and logic coupled to a plurality of network interfaces. The logic is operable to: receive address information that identifies a packet flow; generate a synthetic packet based on the address information; provide the synthetic packet to the one or more forwarding logic components; retrieve forwarding information that indicates one or more forwarding decisions for the synthetic packet made by the one or more forwarding logic components; and report the forwarding information. Each of the one or more forwarding logic components is operable to make a forwarding decision for the synthetic packet as part of processing packets in the packet flow, and to store, as part of the forwarding information, data indicating the forwarding decision for the synthetic packet that is made by that forwarding logic component.