Uplink for each Vlan or single link for all?

So my current set up is an edge router ER-X with an Unifi AP and a dumb 5 port switch, I have run out of ports and a couldn’t justify the price of an Unifi switch. A friend of mine gave me a HP Procurve 24 port managed switch so my thought was to split my network up into VLANs. Splitting the 24port switch into a 12port for the main LAN and two 6 ports networks for one for IoT devices that need internet access and one for devices that don’t. Would there be any advantage in having an uplink port on each group to the router or just using one port for all traffic from switch to router? Obviously I understand I’ll use 3 ports instead of 1 but are there any other pros/cons to wiring it up this way
I’ve only had the ER-X and AP for a few months and never had a managed switch before so this is going to be a steep learning curve

normally you would just trunk all tth ports from the switch over to the switch and then tag the other 12 with the VLAN. No need to have two cables from the ER-X unless there is some performance need.

As Tom said, use a single trunk and cable from the Procurve to the ER-X, at least until you determine there is a problem. I would configure the ER-X in vlan-aware mode.

All inter-vlan (between vlan) traffic has to be routed, and assuming the Procurve does not have L3 capabilities, the routing will have to be done by the ER-X.

The ER-X architecture limits the aggregate routed throughput to 1Gb/s. For an explanation see Re-visit the Switch in Edgerouter X which explains that the hard limit is the 1Gb/s link between the switch and the routing engine. Note that a unidirectional flow between vlans has to traverse the switch/CPU link twice, so it can saturate both directions of the full duplex connection.

For traffic in the same vlan, it is all handled within the switch chip and is never even seen by the routing engine/CPU.

Also see the related Re-visit Forwarding Speed in ER-X that deals with the ER-X routing performance.

You didn’t say, but what model is the procurve? Does it have any Gb ports? If it does, you want to be sure to use one for the trunk port. If it is all Gb ports, then try to keep the high volume devices in the same vlan on the Procurve, so that traffic between them never leave the switch.

For example, if you had a NAS for your trusted PCs, it would be best from a performance standpoint to put the NAS and the PCs on the same vlan and all on the Procurve switch. Then the intra-vlan unicast traffic between the NAS and clients will stay on the switch backplane which is much higher bandwidth than a trunk port. Likewise, if you have IP cameras and an NVR; these should be on the same vlan so the traffic does not need to be routed.

Because the ER-X already has an internal 1Gb “trunk” between the Switch in the ER-X to the “routing engine”, there is no performance advantage of using per vlan connections to access ports on the switch. About the only possible advantage would be if you had some devices in the same vlan hanging off switch ports on the ER-X, since that traffic would be contending for the shared trunk link between the ER-X and the Procurve.

And my usual advice is to use the vlan-aware mode on the ER-X if you are using vlans. It’s a bit more complex to setup, but it is a one time pain. It will give you much more flexibility in how you can use the ports on the ER-X.

The IoT devices shouldn’t be using much bandwidth, with the possible exception of video devices like cameras or TVs.

From a logical networking standpoint, lans and vlans are the same. But vlans share resources, so trunk ports and links can become bottlenecks before other links.

Best way to learn is hands on, so good luck and have fun. My advice is to try to understand how things work, instead of just copy/pasting cookbook solutions. Those can get you a working solution quicky, but sometimes the information is stale, and when things don’t work, you will not have any idea why.

Here are some useful references for a new ER-X owner.

Mike Potts’ free pdf ebook on his github page. Here is a direct download link to Ubiquiti Home Network.pdf This has many links to useful source material and gives you an idea of what is possible with an ER-X.

For Edgerouter configuration youtube tutorials, my favorite is Ben Pin whose videos have a high signal to noise ratio, and relatively high technical content.

Here are two that you should watch if you don’t have vlan-aware enabled on your ER-X.

QC Ubiquiti EdgeMAX - Using VLAN 1 on a vlan-aware switch0 Interface

QC Ubiquiti EdgeMAX - UAP with Guest WLAN & VLAN Trunks (VIF)

Thanks for the advice I’ll read/watch and let you know how I get on. This is a over Christmas project to get this all set up
The procurve is a 1810g so all gigabit ports,I was planing on keeping all high traffic on one Vlan so you have confirmed my thoughts