Why the throughput on MQTT transfers might be limited?

Key concept: “Platform throughput” vs “achieved application throughput”

OPSWAT lists Optical Diode 1U throughput configurations as 100 Mbps, 1 Gbps, or 10 Gbps. That defines the platform/license tier capability.

However, achieved throughput can be limited by:

• The licensed throughput tier

• The physical interface speed in use (1 Gb RJ45 vs 10 Gb SFP)

• Broker/server performance, encryption, message sizing, and connector overhead (environment-dependent)

Most common reason for a ~1 Gb/s ceiling: link/interface is 1 Gb

OPSWAT’s setup documentation shows:

• 10Gb SFP ports (e.g., “SFP3 10Gb Ethernet”, “SFP4 slot 10Gb Ethernet”)

• RJ45 LAN ports listed as 1Gb (e.g., LAN1 is 1Gb)

If your MQTT path (broker-facing connectivity) is on a 1Gb RJ45 port, ~1 Gb/s is a practical ceiling regardless of tuning.

Check:

• Which physical ports are used for MQTT/broker connectivity on BLUE and RED

• End-to-end link negotiation (10Gb vs 1Gb) on switches/media converters

Second most common reason: unit is operating at the 1 Gbps tier

Even with 10Gb interfaces present, if the appliance is provisioned/licensed at 1 Gbps, you should not expect sustained 2+ Gb/s. Confirm your purchased throughput level (100M / 1G / 10G).

Practical checklist to target 2+ Gb/s (in order)

1) Confirm throughput tier

• Verify the deployed Optical Diode 1U throughput configuration is 10 Gbps (not 1 Gbps).

2) Confirm 10Gb physical path end-to-end

• Use the 10Gb SFP interfaces for the broker-facing path (where applicable)

• Ensure intermediate devices (switches/media converters) are also 10Gb and negotiating at 10Gb

3) Confirm the connector in use and its tuning scope

• If performance work is being discussed, align the conversation to MQTT connector tuning when MQTT is the protocol in use.

4) Validate broker-side capacity

• Ensure the MQTT broker(s) and destination infrastructure can accept the intended sustained rate (CPU, disk/logging, retention, network stack). (Environment-dependent; confirm with broker vendor metrics.)