C9800 - Point-to-Point link to connect remote Switch

[Tony Rosolek]

Hello world!

What's nowadays the common way to connect a remote building (access switch) via wireless to the (wired) network? In the past often standalone APs configured as Workgroup Bridge (WGB) were used. What's the recommendation today? I don't want to use standalone or mobility express APs. The APs at both ends of the link shall be managed by the C9800 Controller which is already in place. 

Traffic from the remote site (different VLANs) shall be bridged to the trunk port which connects to the FlexConnect AP which will be probably a RAP. Only management and control traffic shall be routed to the WLC and data traffic shall be bridged at the FlexConnect AP. 

RemoteSwitch -> AP (MAP or WGB?) -> over the air -> AP (RAP?) -> LocalSwitch -> Network/WAN -> WLC9800

Is this configuration possible or recommended with a MAP and RAP in Flex+Bridge Mode which are both managed by a WLC?

If yes, I think I need to enable "Ethernet Bridging" and disable "VLAN transparent". 

Thanks in advance!

[Arshad Safrulla]

You already have a solid plan, but with my experience Flex+Bridge mode comes with lot of bugs and limitations. Why not use a dedicated AP for backhaul (if budget permits) and use Flex AP's to serve clients?

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/215100-join-mesh-aps-to-catalyst-9800-wireless.html

[Tony Rosolek]

Hello Arshadsaf, thank you for your fast response!

I'm not sure if Flex+Bridge would be the right choice. I selected it because all other "regular" APs run in FlexConnect mode and I want that the traffic from the access switch, which is connected to the MAP, is bridged directly to the trunk port of the RAP. My understanding is that without FlexConnect mode the traffic is tunneled to the Controller. Is that correct? I did not find any picture or explanation which shows the traffic flow from the clients which are connected to the LAN-Ports of the MAPs. 

There is no requirement to provide any connectivity to wireless clients via RAP or MAP. All I want right now, is to connect the access switch via wireless to the neighboring building (wired network). 

[Arshad Safrulla]

You just need to enable Bridge mode on the RAP and MAP, enable Ethernet bridging. This should allow you to create the P2P link. Since you don't have any requirement to serve clients you don't have to consider Flex+Bridge mode. If the AP is Local mode then the traffic is tunneled back to the client. WLC.

In my previous post why I asked to consider additional Flex connect AP's is because I thought you might be considering the MAP to serve clients as well. In Flex+Bridge mode VLAN transparent is not supported or was not working when we tried.

[Tony Rosolek]

Thanks again for your response!

I had a misconception related to the traffic flow of the wired client traffic. But with your input and further research I now know, that the wired client traffic is always bridged at the RAP switch port. It's never tunneled back to WLC. Local and FlexConnect mode only affect the wireless client traffic.