Why the throughput on MQTT transfers might be limited?

This article applies to MetaDefender Optical Diode / NetWall Diode.

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.)

If Further Assistance is required, please proceed to log a support case or chat with one of our support engineers.
Type to search, ESC to discard
Type to search, ESC to discard
Type to search, ESC to discard
Next to read:
Why are the Metadefender Netwalls showing as disconnected when data cable is in use.
On This Page
Why the throughput on MQTT transfers might be limited?Key concept: “Platform throughput” vs “achieved application throughput”Most common reason for a ~1 Gb/s ceiling: link/interface is 1 GbSecond most common reason: unit is operating at the 1 Gbps tierPractical checklist to target 2+ Gb/s (in order)1) Confirm throughput tier2) Confirm 10Gb physical path end-to-end3) Confirm the connector in use and its tuning scope4) Validate broker-side capacity