I am looking for an OpenWRT router with the following must haves:
5 gigabit Ethernet ports for LAN usage.
Small size. Think on tp-link LS1005G / TL-SG105 / TL-SF1005D as references.
VLAN support. Well, this is actually software, so I guess OpenWRT support is the requirement after all.
I don't care if it doesn't have WiFi. I doesn't hurt, but the antennas would have to be small and fold-able. I can always disconnect them before placing the router in its final location if that helps the small footprint.
I guess the pinned post about the hardware requirements for 500Mbps/1Gbps also applies here. I have no plans of using QoS, NAT or VPNs on the short term, if that helps lower the specs. Basic firewall would be active. Worst case scenario, a plain 5-port 10/100/1000 unmanaged switch would be used.
Five Gbe ports for LAN plus one for WAN? I wasn't sure because you mentioned worst case using a switch.
The Banana PI BPI-R2 and BPI-R64 both have 4 LAN plus 1 WAN, but the WAN port can be repurposed to the LAN if needed.
If you want 5 LAN and a WAN, then the BPI-R3 might also work. It also has 4 Gbe LAN plus 1 Gbe WAN, but then adds two SFP ports you can put Gbe modules in. Board plus case plus a module might put you overbudget though (board+case+adapter runs right around 100€). Depending on what you can get the modules for or if you have any laying around.
Why not go for a small managed switch which would solve your VLAN requirement while still falling inside your cost envelope.
You might also want to read:
as there might be a suitable switch that can be flashed to run OpenWrt, however I am not sure whether these fall within your size requirements.
(When I had to get a switch I went for a model I could install OpenWrt on (Zyxel 8 port managed POE switch), but so far just operate it under Zyxel's OS as it is just a switch)
As long as it's really going to be used as a switch and not as a router: yes. Several users have tried to repurpose their realtek-switches as Routers and were surprised by the bad performance they got. These devices are really designed as switches.
Yes, OpenWrt can make a nicer user interface for a switch (case in point the ZyxelOS GUI is a bit of a mess, but since it matches the manual I am fine with that however Zyxel's GUI does allow to configure the output power per port) but these are no speed-demon SoCs.
I've been happy with a Netgear GS308T managed switch running OpenWrt. Despite its 8 ports, it is still compact in size.
The 5 port ER-X, already recommended, is a great option for something even smaller and with a routing capable CPU in it. Very similar in size and same SoC as the ER-X, the MikroTik RB750Gr3 could be another option.
Thanks,I didn't know about them. They seem to be very capable and well supported.
They are probably big for my needs and more expensive than what I wanted to expend, but deffinitelly worth knowing about them.