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Problem when using 2 APs WAP54GP

Discussion in 'Other Linksys Equipment' started by pmachete, Mar 15, 2006.

  1. pmachete

    pmachete Network Guru Member


    I am setting up a network with 2 APs WAP54GP connected with a hub.

    AP1 <-> HUB <-> AP2

    The AP1: and AP2:
    I am using different SSID and different channels.
    Then I have one PC connected to the hub and one laptop which I connect to the wireless AP1.

    First I connnect the laptop to AP1:

    Laptop <-> AP1 <-> HUB <-> AP2

    The connectivity is fine and I can ping the AP1, AP2 and the PC.
    Then, I disconnect from AP1, I move the laptop to the AP2, and I connect to AP2.

    AP1 <-> HUB <-> AP2 <-> Laptop

    Here is when I start to have problems.
    The connection to AP2 is fine and I can ping it. But, I cannot ping the AP1 or the wire PC.
    This problem happens during 15 minutes, and after this time period the connectivity is back.
    It seems that it is a problem with an agingtime that blocks the AP from forwarding traffic.

    After putting a sniffer in the laptop and the PC, I could tell that the traffic is forwarded
    by the AP from the wireless to the wire but the traffic from the wire to the PC is not forwarded
    to the wireless. This means that any arp sent by the laptop is seen in the wire, but any arp reply
    is not sent to the Wireless.

    Now, the question is why does AP block the traffic only in the wireless direction.

    Any hint on solving this issue?
    Is this a bug on linksys?

    After chatting with linksys support online, they could not give me a solution and they did not consider
    it a bug!!

    Pedro Pereira
  2. howardp6

    howardp6 Network Guru Member

    I am not sure what you are trying to do. Is there any internet connection anywhere or are you trying to file share and printer share between the laptop and PC? Normally the WAP54GP is connected to a switch or router not a hub. Since you do not appear to have a DHCP server anywhere on your network are you using static AP addresses on both the Laptop and PC? Are you trying to setup an Ad Hoc network with the WAP54GPs?
  3. pmachete

    pmachete Network Guru Member

    Hi Howard,

    The real scenario is a Router IOS 806 as a router and having 8 APs running in the same VLAN in a switch. The router will be the DHCP server.
    As I was having problems switching between APs when moving across meeting rooms, I have decided to isolate the problem with 2 APs only and a hub in order to debug the problem. With the HUB is easier to track the problem.
    In my test, there is no DHCP server and I have all hardcoded IP addresses.
    I know that roaming is not supported in these APs. But this is not the scenario here. What I want is to log in to AP1 (like meeting room 1) and then be able to move to AP2 (meeting room to). I would disconnect from AP1 and connect to AP2 (no roaming).

    The main problem is that when a user moves from meeting room, they have to wait 15 minutes for the AP to start forwarding traffic again in the wire -> wireless direction.
  4. howardp6

    howardp6 Network Guru Member

    Are the WAP54GP access points on the same channel and are the SSIDs the same? The WAP54GP is meant for commerical use such as yours and not many of the people on this site have had any exposure to it. The WAP54GP has some logging functionality, did you trying use the WAP54GP logs.
  5. pmachete

    pmachete Network Guru Member

    Hi Howard,

    I am using same SSIDs and different channels.
    I have tried the logging but no related messages.

  6. sillygoose

    sillygoose Network Guru Member

    Is the AP1 still arping for the laptop after it disconnects or does the PC have a stale arp cache that points it to AP1?
  7. Rick_G

    Rick_G LI Guru Member


    Sounds like you and I are pretty much trying to do the same thing. I have 2ea. 2 story buildings ~350 ft apart buy wire. I would like 1ea AP per floor. I really don't care what channel or SSID, don't need seamless.

    Today I installed in building one Cable modem <-> wrt54gr <-> srw224p <-> 2 AP's. I've tried all same SSID's and all same channels; Same SSID's and different channels. I have the "wireless" function router turned off just want to use AP's. Tried one AP upstairs and 1 repeater downstairs.

    I can connect to through router wireless to internet, when turned on, and ping every device. I can log on to 1 AP wireless to internet and ping every device. I can log on to 2nd AP but no or limited connection to internet mostly none. Even when it says no connectivity sometimes I can ping router and yahoo from 2nd AP but that's it. Would this seem like interference from other AP?

    There seems to be very different ideas at tech support for what this network should look like and what should work and what shouldn't.

    Linksys sales says same SSID's and different none overlapping channels 1,6,11 in same area will work. I get 50% signal to 1st AP from equipment room, so repeater should work as well? Tomorrow I'll run new cable to 2nd AP and try separate channels separate SSID's, unless someone else has a better idea.

    Any pointers on signal strength over lap or a different configuration would be appreciated.

  8. Rick_G

    Rick_G LI Guru Member

    This is from linksys KB, the guys at tech "india" say no way only 2 AP's and at best and maybe 2 repeater??


    How to use multiple access points on the same LAN


    How do I use multiple access points on the same LAN


    Multiple access points can be used on the same LAN, provided they are attached to the same hubs or switches that are connected by Cat 5 Ethernet cable.

    The channel for each access point should be unique, within the range of 1-11 for North America. This allows up to 11 access points to be set up on one LAN. It is recommended to go in increments of three to the next closest access point:

    Example: 3 - 6 – 11

    The SSID should be the same for all the units on the LAN

    If WEP is enabled, all WAP11 units must have the same algorithm, passphrase, keys, and tx key in order for the wireless equipped machines to roam.


    Copyright © 2004 Cisco Systems, Inc.

    Wireless roaming with Wireless Access Points

    What is "roaming" and how does it work?


    Roaming is the ability of a wireless computer user to communicate continuously while moving freely throughout an area greater than that covered by a single access point. In such a system, the users end node undertakes a search for the best possible access to the system. First, it evaluates such factors as signal strength and quality. Based on that information the node next selects the strongest Access Point and registers its address. Communications between end node and host computer can then be transmitted up and down the backbone. When a node no longer receives acknowledgment from its original access point, it undertakes a new search. Upon finding a new access point, it then reregisters, and the communication process continues.


    Copyright © 2006 Cisco Systems, Inc.

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