Introduction
In this document Cisco TAC engineer "Siddharth Vij" has explained about 1522 RAP APs causing Switch Port to go into blocked state of STP, if BPDU filter is not applied on the switch port where these APs are connected.
Problem
1522 RAPs connected to a switch port, with STP configured on the switch are causing the switchport to go into the blocked state of STP, as soon as the RAP connects to the MAP. The RAP is joined to a WLC running 7.3.112.0.
The 1522 RAP is connected to a 3750 switch port with the following configuration:
RAP’s Ethernet port (3750 switch)…
00480 interface FastEthernet2/0/15
00481 description Trunk to Test_RCO
00482 switchport trunk encapsulation dot1q
00483 switchport trunk native vlan 204
00484 switchport mode trunk
As soon as MAP AP, also a 1522 joins the RAP, the switchport to which RAP is connected goes into STP blocked state and starts blocking traffic.
If we apply the command "spanning-tree bpdufilter enable" either on the switch port where the RAP is connected or on a switch port where MAP is connected, it work.
This doesn't happens to other 1242 or 1252 APs joining as RAPs on the same controller.
Work Around
The workaround is by making the switch ports to which the RAP and MAPs were connecting as Access Ports, instead of Trunk ports, as the RAPs and MAPs were not carrying any VLANs over to the other side.
Related Information
Mesh Ethernet Bridging: Why Native Vlan 1
Controlling Mesh Access Points
Ethernet Bridging in Point-Point Wireless Mesh Network Configuration Example
