PFC Frames and ECN Packets Monitoring

Overview

OcNOS supports Protocols Supported for DCBX to pause frames using defined times for each of the eight priority classes. This prevents congestion and improves transmission performance by letting the transmitter adjust its data flow according to the receiver’s processing capacity.

Also supports Explicit Congestion Notification (ECN), which provides end-to-end congestion signaling between ECN-enabled senders and receivers in TCP/IP networks. Instead of dropping packets, ECN marks them to indicate congestion, prompting the sender to temporarily reduce its transmission rate until congestion clears. This reduces both packet loss and delay. ECN is defined in RFC 3168.

Feature Characteristics

This functionality enables:

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ECN marked packet monitoring on an interface

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PFC paused frames monitoring on an interface

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Monitored interfaces generate logs, NETCONF notifications, and SNMP traps whenever monitored packets are detected, including PFC frames and ECN-marked packets.

Limitation:

This functionality is applicable to the chips Tomahawk2 (TH2) platforms , Tomahawk3 (TH3) platforms ,Tomahawk4 (TH4) platforms Tomahawk5 (TH5) platforms, , Trident3 (TD3) platforms and Trident4 (TD4) platforms.

Benefits

Improved Congestion Management – Prevents buffer overflows and packet drops by dynamically controlling traffic flow.

Per-Priority Traffic Control – Ensures that critical traffic classes (e.g., storage or real-time applications) are not impacted by congestion in other classes.

Reduced Packet Loss – Uses packet marking instead of dropping to signal congestion, minimizing retransmissions.

Higher Throughput Efficiency – Link utilization can be optimized via adjusting transmission rates based on real-time network conditions.

Prerequisites

PFC monitoring data requires a working PFC configuration and active PFC traffic. Similarly, ECN monitoring data requires a working ECN configuration and active ECN traffic.