L2 Switch Adjacency Detection for LLDP-Unsupported Devices
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Solution Overview
Problem
Existing methods fail to accurately determine the connection of Layer 2 switches to devices that do not support the Link Layer Discovery Protocol (LLDP), especially in networks with multi-stage switches, leading to incomplete topology understanding.
Innovation Solution
A determination apparatus that uses test packets to learn MAC addresses and LLDP reception availability, determining the adjacent switch for devices that do not support LLDP by analyzing MAC tables and LLDP reception status across switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LLDP protocol is used to collect network topology information, then topology grasping accuracy is improved, but devices that do not support LLDP cannot be detected
Solution Approach 1:
The patent introduces test packets as an intermediary mechanism to detect LLDP-unsupported devices. Instead of relying solely on LLDP protocol exchange, the system sends test packets through the network and uses MAC address learning by switches to indirectly detect the presence and connection status of devices that cannot participate in LLDP protocol communication.
Solution Approach 2:
The patent makes the topology detection system universal by implementing multiple detection methods. The switch can handle both LLDP protocol messages and generic test packets, allowing the same infrastructure to detect both LLDP-supported and LLDP-unsupported devices through a unified test packet mechanism.
2Reliability
If test packets are sent to detect LLDP-unsupported devices, then device detection capability is improved, but network communication may be disrupted
Solution Approach 1:
The patent applies partial action by sending test packets only to specific ports where LLDP-unsupported devices are suspected to be connected, rather than flooding the entire network. The test packet transmission is targeted and limited to necessary ports, minimizing interference with normal network communication while still achieving detection goals.
Solution Approach 2:
The system implements periodic test packet transmission at controlled intervals rather than continuous transmission. This periodic approach allows normal network traffic to flow between test packet sends, reducing the likelihood of communication disruption while maintaining effective device detection capability.
3Ease of operation
If MAC address learning is used to determine device connection, then detection method is simplified, but accuracy decreases in multi-stage switch networks
Solution Approach 1:
The patent segments the topology detection process into multiple stages: first using simple MAC address learning to identify potential connections, then using LLDP reception availability checks to verify and refine the detection results. This segmentation allows the system to benefit from both the simplicity of MAC learning and the accuracy of LLDP verification.
Solution Approach 2:
The system uses feedback from LLDP reception status to correct and refine initial detection results from MAC address learning. When MAC learning suggests a connection but LLDP reception is unavailable, the system adjusts its determination accordingly, using the feedback loop to improve accuracy in multi-stage switch networks.
Data Source
AI summary
A non-transitory computer-readable recording medium have stored therein a determination program that causes a computer to execute a process including in a system in which a switch is directly connected to a device that does not support a link layer discovery protocol (LLDP), acquiring, for each switch of a plurality of switches on a connection path of the device, correspondence relation between a port number on a switch side, a MAC address of the device, and link layer discovery protocol reception availability, and determining a switch corresponding to an entry indicating that link layer discovery protocol reception is unavailable among entries in the correspondence relation as an adjacent switch of a device indicating a MAC address of the entry.