Cisco Access Point works at home, but not at church! :-)

[BGriswold@AOL.COM]

The church (for which I'm volunteering my time) has an existing Cisco Access Point (AIR-AP1852I-B-K9) that's working just fine.  I have configured a second access point - exact same model (AIR-AP1852I-B-K9) - and am experiencing difficulties getting it to work at church!

When I power it up at home, it works just fine - as expected (in the sense that it 1) Broadcasts an SSID 2) Allows me to connect to it and 3) Give me access to the wired network to which it is attached).  However, when I power it up at church, it does not broadcast an SSID, does not respond to PINGs.  I SUSPECT the reason it's behaving differently at church than it does at home may be due to the fact that the 'already existing' AIR-AP1852I-B-K9 at church acts as a controller and is configuring the 'new' AIR-AP1852I-B-K9 differently than how I've configured to work.  

I'm well familiar with TCP/IP networking, well familiar with LOW COST access points, but unfamiliar with modern Cisco products, unfamiliar with deploying access points that are configured by a controller, and my Cisco skills are about 20 years out of date!   

I know how to do TELNET to the serial port, how to configure the unit via the browser, etc.

Any general direction/tips on how I should go about troubleshooting this?

Thanks in advance for any input!

Bill Griswold

BGriswold AT   AOL.COM

[Leo Laohoo]

I think the 2nd AP needs to be loaded with Mobility Express so it can act as both as a WLC and an AP.

[pieterh]

first check IP addresses on the LAN connection!

1) if you configured the same address as the existing AP then the ap won't boot with "duplicate IP" error

2) if you configured the LAN interface of the AP with another fixed address then this may not be in the same subnet as in the church

3) if you configured the LAN interface as to acquire a DHCP address, there may not be a DHCP server on the churches LAN but you need a fixed address

4) the router in the church that connects to the internet may not allow this new device!

if you can connect to the serial console of the AP (blue port) you may see messages in the console log that give you the necessary information

[BGriswold@AOL.COM]

Thanks for double checking my thinking!

1) if you configured the same address as the existing AP then the ap won't boot with "duplicate IP" error

VERIFIED:  I have configured it with a unique IP address not in use anywhere else on the network.

2) if you configured the LAN interface of the AP with another fixed address then this may not be in the same subnet as in the church

VERIFIED: It has been verified that the unique IP address is in the same subnet as is in use in the church.

3) if you configured the LAN interface as to acquire a DHCP address, there may not be a DHCP server on the churches LAN but you need a fixed address

VERIFIED: There is a DHCP server on the church LAN, but in any event, I have configured with a fixed IP address.

4) the router in the church that connects to the internet may not allow this new device!

VERIFIED: The router that connects to the Internet does not case that such a device is on the network.  Besides, the communication we're attempting (to PING the access point from elsewhere on the LAN) doesn't go through the router.  In addition, we already have another access point of the same make & model on the network.

Thanks again for double checking my thinking!

Any other thoughts on what might be going on, anyone?

[pieterh]

1) is it possible to disconnect the existing access point before connecting the additional one?

At least then there will be no conflict between the two! and you can confirm whether the existing ap does influence the new ap.

2) did you get any output from the console port?

3) can you login into the router to see what devices are connected to the LAN?

do this before and after you connect the accesspoint to the lan? to see if a new device apears and what ip-address is has.

4) you do static configuration:  does the default gateway point to the router?

[BGriswold@AOL.COM]

1) is it possible to disconnect the existing access point before connecting the additional one?

At least then there will be no conflict between the two! and you can confirm whether the existing ap does influence the new ap.

Excellent idea?  I've been assuming that the new AP I'm introducing is being 'controlled' by the existing one - good recommendation to 'confirm' this assumption by disconnecting the existing one. Will try that!

2) did you get any output from the console port?

I don't have a console cable (nor a computer with a serial port), unfortunately.  I've configured it using HTTP.

3) can you login into the router to see what devices are connected to the LAN?

do this before and after you connect the accesspoint to the lan? to see if a new device apears and what ip-address is has.

The router doesn't know what devices are connected to the LAN, other than by knowing the MAC & IP addresses from which it has received packets.

4) you do static configuration:  does the default gateway point to the router?

Yes, we have configured its default gateway to be the router - but we're trying to ping from another node on the same subnet, so that router doesn't even come into play.

[pieterh]

some more questions

are there any other network components involved in the path between the new ap and the host you are "pinging" from.

in your own network do you use manageable switches ? and maybe the AP is using vlan tagging to the network? the network at the church may not recognize this.

[BGriswold@AOL.COM]

are there any other network components involved in the path between the new ap and the host you are "pinging" from.

Just a managed switch.  

in your own network do you use manageable switches ? and maybe the AP is using vlan tagging to the network? the network at the church may not recognize this.

Excellent lead!  I'll have to try an unmanaged switch to see if that makes a difference!

[sbarreto]

Hi Bill,

New Cisco APs can work in two modes: Mobility Express (standalone), where AP will act as controller and as AP; and CAPWAP, for which you need a controller to associate to.  Check the following link:

http://www.cisco.com/c/en/us/td/docs/wireless/access_point/mob_exp/1/user_guide/b_ME_User_Guide/getg_start.html#task_B167539A1E9D45CBA877C47EBE4D78D2

If you already have one AP working as Mobility Express in church, you may want to convert the second one to CAPWAP and have it associated to the first one.  Once an AP is in CAPWAP mode, it needs to discover the controller. Check the following link to understand this process:

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/70333-lap-registration.html

Hope this helps.

Thanks,

Sergio.

[BillGriswold]

Thanks, Sergio! Those articles are filling in some gaps in my knowledge about 'light weight' APs, which I know little about!  :-)

[BGriswold@AOL.COM]

OK - Was not aware there were two modes (CAPWAP Lighweight AP Software or Mobility Express Software) that might be installed. I have three questions on this:

Q1) The article Sergio provided describes how to determine which is installed by connecting to the console port. Does anyone know how to tell which is installed by connecting to the AP via HTTP?

Q2) Is the fact that I CAN connect via HTTP an indication that the Mobility Express Software is installed?

Q3) Is there any problem having three Cisco APs running Mobility Express Software on the same LAN?

[pieterh]

the fact that the AP works at home suggests you al ready have a real controller or an access point (this one) acting as controller at home! 

[BGriswold@AOL.COM]

Duh!  Should've figured that one out myself!  Thanks Pieter!

[tomynicolus20108]

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