Unifi Inter-vlan routing broken on UDM Pro Max?

Networking & Firewalls
1

As the title says I have a UDM Pro Max where the inter-vlan routing is functionally broken.

Running iperf3 between two clients on the same vlan give speeds of ~2.22Gbits. When running it across two vlans with the same devices, cables and ports the speed drops to ~1.2Mbits.

I have tried many different things (which I will discuss below) but I am out of ideas and looking for any other advice.

Original Setup

In my original setup where inter-vlan routing was working, it was UDM → Aggregation → USW Gen 1, each connected with 10G DAC cable. I Wanted to change this setup as I was running several devices with RJ45 to SFP+ modules that were running at 100F. So, I purchased a Unifi 8 port 2.5g switch.

Second Setup

In my next setup I replaced the aggregation with Unifi 8 port. It looked like UDM → USW Gen 1 → 8 port, each connected with 10G DAC cable. This is where my inter-vlan routing issues started. Since replacing the Aggregation switch I have not been able to get proper speeds.

Current Setup

From what I could find online some people said it could be a routing limitation of the UDM Pro Max, and they recommended using layer 3 routing. So I picked up a USW Pro Max 48 to replace the USW Gen 1 and 8 port switch. Current setup is UDM Pro Max → USW Pro Max with 10G DAC Cable.

Troubleshooting

  • Restarted UDM Pro Max
  • Shutdown and unplugged UDM Pro Max
  • Replaced USW Gen 1 and 8 port switch with USW Pro Max 48
  • Enabled layer 3 routing for two vlans. Speeds did not change Layer 3 routing is currently disabled
  • Removed all QoS rules
  • Removed all block rules between vlans

I have a pfSense box I could setup to see if it has the same inter-vlan routing issue, but even if it does work, I don’t know what it would tell me that I don’t already know, i.e. that inter-vlan routing is broken on my UDM Pro Max.

2

Correct me if I’m wrong…. But isn’t this just the overhead from having to route between vlans?

The difference being smaller with the more expensive the firewall, speciality asics, cpu power propriety algos etc etc….

3

I don’t have one handy to test but the inter VLAN routing speed for a UDM Pro should be around 8 Gbps using Multi-Stream TCP, No IDS/IPS. I would drop a bit depending on the rules and if you turn on QoS & IDS/IPS.

I would start digging trough /var/log/ or looking into other factors with the devices you are using test the performance with.

4

Hi @LTS_Tom Thanks for the advice.

Before I started digging into the logs of the UDM I figured I could try a couple more tests.

I tried a different computer and found that the iperf speeds did not improve. But after only running iperf tests, I figured I would give transferring linux iso’s between my NAS and computer a try again (the thing that started this whole investigation and testing) and wouldn’t you know it, I’m able to hit 2.2Gbps on transfers.

At this point the only difference is the new USW Pro Max switch, everything else is the same. So, I’m not sure when or why it started working or why the iperf tests are still terrible across vlan but line speed when on the same vlan.