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The Product

Recently I purchased a nice new Cisco 867w as I needed another router, and it didn’t really warrant the expense of an 887w or larger for the task at hand. I am reasonably familiar with configuring Cisco switches, security devices (ASA, PIX etc) and routers, and can find my way around the IOS fairly well, or so I thought. I haven’t really had much to do with Cisco Wireless APs and general AiroNet products as I am still not a great wireless fan apart from where necessary. I have configured lots of 87xW series and 18xxw series with integrated wireless capabilities and the general concept of bridging the Wireless interface to the Vlan or FE interfaces is pretty straight forward.

But the 867w (and 887w) has a full Cisco AP embedded in to the router. The AP has it’s own IOS and needs a full configuration, and even more alarmingly, I could not find any sample wireless configurations anywhere on the net, including on the Cisco.com site. There is a good configuration guide on the Cisco site but it falls way short of the mark to configure the router from scratch. It is much better as a reference guide. I couldn’t find any reference in it to how the 867w’s AP actually integrated, and hence, communicated with the router itself.

Another major issue for me was that the router shipped with an old IOS and apart from that absolutely nothing in the flash. (Pretty sloppy Cisco!)

The Problem

My problem, in a nutshell, was how to bridge the AP to the router’s vlan. Sounds simple enough doesn’t it. But I couldn’t see an obvious solution and couldn’t find any relevant documentation. I posted on a couple of quality forums to see if anyone else had had a similar issue, and yes lots of people had. What was the solution? None given. Grrr… There are loads of posts pointing to the concept of bridging VLANs and the concept of configuring a router but no wireless sample configs. Personally I find it beneficial when faced with a new device to see a working Config, pull it apart and figure out why it works. I learn the most that way.

So I did the only logical thing I could do, and went to the cupboard and got out an old 877w and ran it up instead. Aaahhhh… the comfort of familiarity. But of course I love technology so I couldn’t let it beat me.

To cut a very long story short, there is a Wlan-GigabitEthernet 0 interface visible in both the Router and the AP configuration and this is the glue that binds the Router to the AP. So, below I have included the running config for each of my relevant interfaces on both the Router and the embedded AP.

Don’t forget that, until you configure a management ip on the AP’s BVI1 the only way to configure the AP is by logging on to the router and the using

Router# service-module wlan-ap 0 session

to get into the AP config. Once in there the only way to get back is to use

AP# <Shift>+<Ctrl>+6 X

to get back to the Router’s Configuration mode. This leaves the AP config session open. If you subsequently want to close that session you also need to type

Router# disconnect

to close it completely.

The Solution

On the Router…
interface Vlan1
 ip address 192.168.xx.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
end
!
interface Wlan-GigabitEthernet0
 description Internal switch interface connecting to the embedded AP
end
!
interface wlan-ap0
 description Service module interface to manage the embedded AP
 ip unnumbered Vlan1
 arp timeout 0
end
!
interface Dialer0
 description PPPoA Dialer for Int ATM0
 ip address negotiated
 ip access-group aclInternetInbound in
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip mtu 1492
 ip flow ingress
 ip nat outside
 ip virtual-reassembly
 encapsulation ppp
 dialer pool 1
 ppp authentication chap callin
 ppp chap hostname
 ppp chap password
 ppp ipcp dns request accept
 ppp ipcp route default
 ppp ipcp address accept
 no cdp enable
 crypto map
end

Of course there is no necessity for the

ip route 0.0.0.0 0.0.0.0

due to the ip ipcp route default on the dialer interface.

On the AP
interface Dot11Radio0
 no ip address
 no ip route-cache
 encryption mode ciphers aes-ccm tkip
 broadcast-key change 3600
 ssid
 antenna gain 0
 speed  basic-6.0 basic-9.0 basic-12.0 basic-18.0 basic-24.0 basic-36.0 basic-48.0 basic-54.0 m0. m1. m2. m3. m4. m5. m6. m7. m8. m9. m10. m11. m12. m13. m14. m15.
 station-role root ap-only
 bridge-group 1
 bridge-group 1 subscriber-loop-control
 bridge-group 1 block-unknown-source
 no bridge-group 1 source-learning
 no bridge-group 1 unicast-flooding
 bridge-group 1 spanning-disabled
end
!
interface GigabitEthernet0
 description the embedded AP GigabitEthernet 0 is an internal interface connecting AP with the host router
 no ip address
 no ip route-cache
 bridge-group 1
 no bridge-group 1 source-learning
 bridge-group 1 spanning-disabled
end
!
interface BVI1
 ip address 192.168.xx.2 255.255.255.0
 no ip route-cache
end

And on the AP you will need a default route, so you will need a

AP(config)# ip default-gateway 192.168.xx.1

to tell the outside bound traffic how to get out to the world at large through the Router’s VLAN interface.

Edit:  A few people have asked for a full AP config to get started with so here is a “Bare Bone” one to get you started…

version 12.4
no service pad
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime localtime
service timestamps log datetime localtime
service password-encryption
hostname AP
logging buffered 132000 notifications
enable secret 0 <PutAGoodPasswordHere>
no aaa new-model
clock timezone AEST 10
clock save interval 8
dot11 syslog
dot11 ssid SSID
   authentication open 
   authentication key-management wpa version 2
   guest-mode
   wpa-psk ascii 0 <PutAGoodPasswordHere>
username me privilege 15 secret 0 <PutAGoodPasswordHere>
bridge irb
interface Dot11Radio0
 no ip address
 no ip route-cache
 encryption mode ciphers aes-ccm tkip 
 broadcast-key change 3600
 ssid SSID
 antenna gain 0
 speed  basic-6.0 basic-9.0 basic-12.0 basic-18.0 basic-24.0 basic-36.0 basic-48.0 basic-54.0 m0. m1. m2. m3. m4. m5. m6. m7. m8. m9. m10. m11. m12. m13. m14. m15.
 station-role root ap-only
 bridge-group 1
 bridge-group 1 subscriber-loop-control
 bridge-group 1 block-unknown-source
 no bridge-group 1 source-learning
 no bridge-group 1 unicast-flooding
 bridge-group 1 spanning-disabled
interface GigabitEthernet0
 description the embedded AP GigabitEthernet 0 is an internal interface connecting AP with the host router
 no ip address
 no ip route-cache
 bridge-group 1
 no bridge-group 1 source-learning
 bridge-group 1 spanning-disabled
interface BVI1
 ip address 192.168.xx.2 255.255.255.0
 no ip route-cache
ip default-gateway 192.168.xx.1
no ip http server
no ip http secure-server
bridge 1 route ip
line con 0
 no activation-character
line vty 0 2
 exec-timeout 20 0
 login local
 transport preferred none
 transport input telnet
line vty 3 4
 exec-timeout 20 0
 login local
 transport preferred none
 transport input ssh
 transport output all
sntp server <IPofSntpServer>

I hope that helps.