What Is Packet Event?

Why Do We Need Packet Event?

Packet Event provides the following functions:

• Packet loss visualization: If packet loss occurs on a device, services are affected. Packet loss visualization enables fast detection of packet loss on devices caused by abnormal forwarding, specified packet discarding rules, full buffer, or deny action in ACL rules, implementing quick fault locating.
• Latency visualization: If the latency of packets exceeds a specified threshold, network congestion occurs. Latency visualization enables devices to promptly detect packets with a high latency, preventing network congestion.
• Fault self-healing: When packet loss occurs on a network due to specific causes, it can be detected and self-healed in real time, improving network reliability.

How Does Packet Event Work?

On the network shown in the following figure, packets sent from a host and forwarded by devices may be discarded on a device due to the following causes:

• A forwarding exception: Packets are discarded in abnormal scenarios such as chip entry loss, chip entry delivery error, and packet check error.
• Specified packet discarding rules: The packet loss is predictable. For example, port isolation is configured to discard packets between two specified ports, a punishment action such as traffic suppression associated with MAC address flapping is configured, or split horizon is configured on ports.
• A full buffer: The buffer of a port or queue is fully occupied, resulting in the discarding of excess packets.
• ACL rule deny actions: Packets that match such ACL rules will be discarded.

After packet loss visualization or latency visualization is enabled on a forwarding device, corresponding flow entries will be generated in the device's CPU if packets are discarded due to any of the preceding causes or the latency of packets exceeds the threshold. The device periodically reports the flow entries to the collector through UDP packets in NetStream V9 format. The analyzer reads the data from the collector, analyzes the data, and detects the cause and location of the exception in a timely manner. In this way, faults are quickly located to prevent network congestion. In addition, the device can detect packet loss due to specific causes and take corresponding self-healing measures based on the specific cause IDs, further improving network reliability.

Packet Event