How to Interconnect Two QNAP QSW Managed Switches
Applicable Products
QNAP managed switch
Scenario
You have a QSW-M2106-4C and a QSW-M408-2C and you want:
More access ports without replacing hardware
A 20GbE aggregated backbone between switches
Clean segmentation with VLANs, e.g. VLAN 10 (LAN), 20 (IoT/Printers), 30 (Guest), 99 (Mgmt)
Solution
To connect two QNAP managed switch(e.g.: QSW-M2106-4C and QSW-M408-2C), Here’s a clean way to link them.
1) Physical uplink
Use 2× SFP+ DAC cables, then plug into any SFP+ on both switches. This is the simplest, cheapest, and most reliable for short runs.
Recommended: build a 2-port LACP LAG between the switches for more bandwidth + failover. Both models support LACP/link aggregation and 802.1Q VLANs.
e.g.: ports 9 an 10.
2) Configure the inter-switch link (QSS web UI)
Do the same steps on both switches.
2.1 Create the LAG (skip if single link):
QSS (switch web) → L2 Features → Link Aggregation → Enable LACP → Add LAG1 → select the two uplink ports → Mode: Active → Apply.
2.2. Create VLANs:
QSS → VLAN → 802.1Q VLAN → add your VLAN IDs (e.g., 10=LAN, 20=IoT, 30=Guest, 99=Mgmt). On each VLAN row, set LAG1 as “Tagged” (so it carries all VLANs between the switches).
