Access point multiple routes

#1

Hello community,

I've been playing around with the idea of a "centralized AP" and wondering if that's even possible (given the hardware supports spawning enough Wi-Fi networks).
The idea is quite simple:
Use a router as "dump" AP, but for multiple SSIDs - Ok what do I mean with that?
I have two separate routers (which I can't replace for various reasons) and it would be neat to have only a single access point for Wi-Fi devices, which will route the traffic to the corresponding router, which will then take care of the proper routing further itself (be it outside (to the internet) or inside (to another subnet/VPN) or whatever).

As example:
2,4GHz + 5GHz SSID: Office -> Route traffic to office router
2,4GHz + 5GHz SSID: Home -> Route traffic to home router

I've a TP-Link Archer C7 v5 here and would like to realize it like that.
I would just go ahead and configure it as "dumb AP" and plug in LAN 1 the office router LAN and in LAN 2 the home router LAN.

Is this a possible scenario?

I'd appreciate any advice - thanks alot!

Cheers,
Steffen

#2

Yes, that's possible. Just make a VLAN for each network, and then create/add the SSIDs to the appropriate Interface/VLAN.

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#3

Hello lleachii,

thanks for your answer.
When it comes to VLAN I am a total noob and this really goes over my head.
I have a couple of questions regarding this and someone might be able to answer this:

  • If I start applying VLAN tagging I guess I have to apply the tagging on all routers and switches. Is that correct?
  • From what I understood from a quick research I only need to apply the tagging on the switches and routers, so the "end-devices" are not concerned with this, correct?
  • I do have (luckily) only managed switches, which are capable of VLAN tagging - going forward with VLAN tagging I assume I cannot integrate "dumb" switches anymore, correct?
  • I do have a pppoe-pass through on my modem (DrayTek Vigor 165), so I do the pppoe-dial-in via my router, but the modem applies VLAN tag 7 (for Deutsche Telekom) on the way out. Do I need to change the behaviour, so that I do the VLAN tagging on the router?
  • My assumption was I can plug in direct connections from the access point to both routers via separate LAN cables and both routers are not connected to each other directly. Why do I need VLAN tagging? As those are separate cables - I assume because the traffic on the access point comes in on a single interface and can it only be distinguished which route to take based on the VLAN tag applied, is that correct?

I attached a PNG (unfortunatly I couldn't attach a PDF or similar) with my network plan (I am doing such a plan the first time, so please bear with me! :))

Thanks beforehand for any advice!

Cheers,
Steffen

#4

No.

No.

No.

No.

You can.

You don't, you just need to define another VLAN in the OpenWrt if your AP can physically connect to both networks. Your ports can be untagged, hence no tagging or trunking. I think you're trying to make things too complex. See the graphic on the web GUI at Network > Switch for an easy guide.

Also, per the Community Guidelines, please refrain from signing your posts.

#5

Thanks for your answers, I have a follow up question to the answer of you on one of my questions:

From what I understood from a quick research I only need to apply the tagging on the switches and routers, so the "end-devices" are not concerned with this, correct?

No.

If I interpret your answer correctly, tagging needs to be applied also for the "end-devices"? Seems a bit cumbersome.


Okay, I don't get it.
I just took a look at https://openwrt.org/docs/guide-user/network/vlan/switch_configuration to understand, the concept of VLANs in OpenWrt.

There it says within the section VLAN explained with default scenario of most OpenWrt routers

  • Tagged on “CPU (eth0)” means that the two VLAN ID tags used in this example (1, 2) are sent to the router CPU “as tagged data”. Remember: you can only send Tagged data to VLAN-aware devices configured to deal with it properly.
  • Untagged means that on these ports the switch will accept only the incoming traffic without any VLAN IDs (i.e. normal ethernet traffic). The switch will remove VLAN IDs on outgoing data in such ports. Each port can only be assigned as “untagged” to exactly one VLAN ID.

What I get from the text is "if you do tagging, make sure your network hardware is capable to do it". Or is it only meant for the router itself and doesn't concern any other network hardware at all?

So I read further down and there are what is called "software VLANs" (section: Creating driver-level VLANs).

I am a bit confused right now. Is there any difference between those things? What do I need to apply?

Your ports can be untagged, hence no tagging or trunking.
So there is a difference between a VLAN and VLAN tagging or trunking?

Sorry for the questions, that might seem straight forward for you (or any other experienced network engineer), but as said, I am really new to VLANs (or "complex" networking in general).

Really appreciate your help!

#6

No tagging on end devices. I understand that you have 2 free ports on your AP, just declare each one untagged on their own VLAN. THIS VLAN ONLY NEEDS TO EXIST ON THE OpenWrt AP. Simple.

:confused:

Basically...but both understandings are slightly wrong. In most OpenWrt devices there is a switch, that has one phy called eth0. In order to use the switch's ports, VLANs must be declared. VLAN 1 is commonly used for LAN and VLAN 2 for WAN. Cisco devices are also common for needing VLANs declared before usage in this manner.

I'm suggesting you use VLAN 1 (already existing) and create a VLAN 3. You do not have to mark the ports at tagged, as you will use 2 Ethernet cables for this setup. You DO have to mark the CPU (eth0) as tagged.

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#7

Thank you very much for the clarification.
I think I somehow mixed VLAN and VLAN tagging and this is what got me confused.

Will try this as you adviced tomorrow - thanks again!

1 Like