When a client is connected over a WAN link associated with a centrally switched WLAN wants to send some data to a device in local site, then the client has to send the traffic over CAPWAP to the controller and then get the same data back to the local site over CAPWAP. This consumes WAN link bandwidth as the same data is send and received. This can be avoided to utilize the WAN bandwidth efficiently.
FlexConnect Split tunneling feature helps avoid such scenario by classifying the data send by the client based on the packet contents using FlexConnect ACL. The matching packets are locally switched and the rest of the traffic is centrally switched. The traffic that is sent by the client that matches the IP address of the device present in the local site can be classified as locally switched traffic and the rest of the traffic as centrally switched.
FlexConnect ACL feature allows to create a filter that can be applied on FlexConnect AP for protection of locally switched data traffic from the AP.
FlexConnect ACLs are created on the WLC and then be configured with the VLAN present on the FlexConnect AP.
Supported Access Points:
Split Tunneling supported on the AP1040, AP1140, AP1260, AP2600, AP3500, and AP3600 access points.
Split tunneling is not supported on Cisco 1500 Series, Cisco 1130, and Cisco 1240 access points.
To configure split tunneling on a per-AP basis, enter this command:
config ap local-split enable wlan-id acl acl-name ap-name
The split tunnel access-points, with the controller code Release 7.5, allow clients (that connect to the corporate SSID) to connect to the corporate resources and access local resources simultaneously. It is available for clients that connect through the corporate SSID and the remote LAN. This feature presently supports the split tunneling for printers with the common printer ports such as PDL (port:9100), IPP (port:631), MFP (port: 9303), LPR (port:515), PSUS4 (port:34443), and Generic printer server (port:35).
The Packet Flow Process
1. AP inspects the traffic sent by the client to the corporate network for the well-known printers. 2. When the client is configured with a gateway, it sends all packets to the destination MAC address of the gateway. In this case, when the client is connected to the corporate SSID with the destination MAC address of the gateway, the SSID tries to connect to the printer 192.168.1.100. 3. The AP finds a match for the printer port and sends out an Address Resolution Protocol (ARP) request on the local network for the destination IP address of the printer. 4. When it receives a reply, it changes the destination of the MAC address. It changes from the gateway's MAC address to the printer's MAC address and forwards it to the local network. 5. The AP bridges back the reply traffic from the printer to the client.