Standalone AP Console prompt not visble !!

[manju.cisco]

Hi All,

Today we were asked to install autonomous (Standalon) Access Point (AP1242AG)installation remotely with a technician help at onsite.

The AP was fresh and out of the box with factory default settings.

When the technician tried to connect to the AP through console cable, he was unable to get console prompt.

He verified the cable by connecting it to Router and he was able to see router prompt, when he puts back the console cable to the AP he doesnt get any prompt

The console settings for 9600 baud rate, 8 data bits, no parity, 1 stop bit and no flow control were set properly.

Any idea, why i was not able to see the AP through the console ???

The AP was powered on though PoE where the ethernet port was connected to the Switch.

Thanks in advance.

Manjunath

[Peter Paluch]

Hello,

Interesting. The technician should have seen at least some messages during the AP bootup.

The natural recommendation is to try resetting the AP using the RESET button and to go over all supported COM port speeds to see if the AP starts responding - perhaps it is not as pristine as it appears.

Best regards,

Peter

[manju.cisco]

Hi Peter

Tech couldnt see anything on his screen.

Tried reseting to factory defaults using mode button, but still he cannot see anything on the screen.

Tried both external and PoE power source, still nothing happened.

If he connects the same console to router, he gets router prompts, but he is not able to see console on this damn AP

any thoughts again ?

[ankugarg]

Bad hardware ?

[Peter Paluch]

Hi Manju,

Is the AP booting at all? After a couple of minutes, how do the LEDs light/flash? Did you or the technician try to go over the available COM ports speeds?

Best regards,

Peter

[manju.cisco]

Hi Peter,

Onsite tech said he see lights as green,green, off.

AP does boot fine, i can see it in connecting Switch cdp neighbors.

However, we didnt try to go over the availble COM ports speeds, we just tried 3 speeds

[Peter Paluch]

Hi Manju,

Trying all speeds would certainly be wise in this situation. Note that the usual speeds are in this set: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. I have not seen Cisco devices run their consoles on other bit speeds.

If you see the device in show cdp neighbor command, can you also check if the device has an IP address? Use the show cdp neighbor detail to check that. If yes, you may be able to configure your PC for a common IP subnet and then connect to the device using either HTTP or Telnet/SSH via Ethernet.

Best regards,

Peter

[manju.cisco]

Hi Peter,

Yes i had used show cdp neighbor detail and saw no ip address.

I thought it would have default ip address of 10.0.0.1 by default so i did try giving ip to the switch port as  10.0.0.2 and did a ping but failed.

The AP didnt had any ip in it

[Peter Paluch]

Hi Manju,

I see. Good thinking, anyway!

Perhaps the AP is configured to obtain its IP address via DHCP. Would you mind connecting it to a network segment with a workable DHCP service, and perhaps wait a couple minutes if it obtains an IP address automatically? You would be able to see it in the CDP afterwards.

Best regards,

Peter

[Gregory Brunn]

Peter,

I have run into this before.  By default the AP will look for a dhcp address however you should be able to get into the unit through the console port.  I have actually run into this very problem before.

Check your techs console port settings.  I would use webex or a remote desktop client to do this. 

See below

Use these port settings:

Speed:	9600 bits per second (bps)
Data bits:	8
Stop bits:	1
Parity:	None
Flow Control:	Xon/Xoff

Note: If the flow control Xon/Xoff does not work, try using the flow control None.

If this still does not work and you are unable to get a dhcp address and you have the devices mac address you could always try getting into the unit by staticly assigning the mac address to an ip address locally on your machine.

The command on windows is like this

arp - s ip address mac address or arp -s 192.168.1.5 00-aa-bb-00-aa-bb

Let me know if this helps

-Greg

[Peter Paluch]

Hello Greg,

Thank you for your response. I am not having a problem - Manju is According to what he has indicated here so far, he tried to use both the default COM port settings and some other speeds but the console of the AP remains unresponsive. It looks as if either the console is deactivated, moved to a different speed or is damaged.

I do not quite understand your suggestion about the static IP/MAC mapping in the ARP table.

Best regards,

Peter

[Gregory Brunn]

Sorry Peter for the confusion. The static assignment is an attempt to have a pc talk to the AP without having a address learned through dhcp.

Manju when I had this problem it was with my flow control setting.

Peter I see and agree with what you are stating above I know that from my experience my console settings worked on all my other lab routers but not the AP until I fooled around with the flow control.

Hopes it helps

Sent from Cisco Technical Support iPhone App

[Peter Paluch]

Hello Greg,

The experiment with the flow control setting is reasonable. Manju, would you mind testing Greg's hypothesis as well?

One comment about the static ARP entry, though: I do not believe it would help. You can not expect that you can talk via IP to a device just because you know its MAC address. Even if you encapsulate an IP packet into a frame destined to a particular node, it will process that IP packet only if it owns the destination IP address. Otherwise, it will acept the frame - but drop the IP packet.

Best regards,

Peter

[Gregory Brunn]

Peter,

Interesting point about the static arp. I would like to try this in lab at some point. My assumption was ip is layer 3 protocol and being on a local segment only layer 2 protocols would be needed. So if a locally connected device received traffic and did not know about the source it would just arp for it. But this is of course getting off subject from the original console issue.

Manju please let us know if the flow control is indeed the issue like I have found for me in the past. Hopefully it is.

Greg Brunn

Communications Engineer

ICS

Mobile: (443)822-9943

Please excuse typos sent from mobile device.

[Peter Paluch]

Hi Greg,

My assumption was ip is layer 3 protocol and being on a local segment  only layer 2 protocols would be needed.  So if a locally connected  device received traffic and did not know about the source it would just  arp for it.

Oh, no, that is not the way things work. Even if IP is Layer3 protocol, it does not mean it can not be used when communicating on a local segment. If we talk about IP networks then irrespective of local/remote communication, there must always be an IP packet that is delivered between a source and a destination. The fact that the IP protocol is a Layer3 protocol means that it is capable of delivering data between any end hosts located anywhere - in the same network or in two different networks.

This is very easily demonstrated: just ping your own default gateway. It is in your own network, yet the pings will be encapsulated into IP+ICMP protocol suite.

Best regards,

Peter