Wireless Access

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Access network design for branch, remote, outdoor and campus locations with Aruba access points, and mobility controllers.
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205 Access Points Not Receiving Proper IP Address from Trunk Port

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  • 1.  205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted Mar 19, 2021 01:45 PM

    I have a handful of 205 Access Points that suddenly stopped broadcasting on our default configuration. The devices power up and get an IP address, but it is not from the tagged or native vlan that has been set on the trunk port. If I place the port into access mode the AP comes online but does not broadcast all the vlans we need it too--only the access mode vlan. 

    When I plug my computer into the same cable, I receive an IP from the correct vlan. 

    When I connect the AP to the console and break the boot sequence and run dchp. The ap gets an ip from the correct vlan. But when I reboot the AP it reverts back to the IP from the vlan that will not bring the AP up.

    Previously we ran APs on IPs from multiple vlans but all the down APs show on up one vlan and that is the  vlan down APs  are reverting to for an IP address.

    Thought this might be a switchport issue but after this troubleshooting I'm inclined to think it is an issue happening with the APs.

    APs come up on our 10.50 vlan (tunnel)
    APs are not coming up on our 10.0 vlan (bridge)

    Thanks for any thoughts



  • 2.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted Mar 20, 2021 05:24 AM
    As far as i get you right, what  you have to do is the following:

    1. Place the switch port where you connect the access point as Access and place the VLAN which  you will use as "management" VLAN, lets say vlan 100, for the AP to communicatee with the Wireless Controller.
    (usually you want to have this VLAN separated from the clients/subscribers VLAN who will want to use the Internet through the SSID)

    2. Then you configure the SSID with multiple types of VLAN if  you want (maybe each SSID have a different VLAN, or configure named VLAN where for a name, lets say staf-vlan you add vlan 10,20,30 and guest-vlan you add vlan 40,50,60)
    (this works like QinQ) 

    So the Client will get IP Address from VLAN 10,20,30,40,50,60..... but the uplink will have only 1 vlan (VLAN 100).


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    Shpat
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  • 3.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted Mar 20, 2021 09:53 AM
    Thank you very much for your response.

    This is informative. I do not know all of the details of how the VLANs are configured on the controller. This is my third month on the job and I am still trying to figure out how the network topology was constructed.

    Here's what I can tell you.

    We have a Staff Vlan: 10.0.0.0-Vlan 2
    We have. Student Vlan 10.50.0.0-Vlan 50
    We also have a guest VLan.

    Default switchport configuration for all APs is

    Administrative Mode: Trunk
    Access: Vlan 2
    Native Vlan Trunk: Vlan 50

    All other APs are getting an IP from Vlan 50 on this configuration except the three that have gone down. All three are Aruba 205 APs.

    For some reason, on the switchport, toggling administrative mode from trunk to access, assigning the access vlan to vlan 50 then toggling the settings back to trunk mode, and changing the access vlan back to vlan 2 brought two of the down APs back up. This has not worked on the remaining three down APs.

    From what I understand, the APs should broadcast all three ssids regardless of the Vlan they receive an IP address from. We also have a guest Vlan and some of our APs are up on IPs from that VLAN!

    I thought our management vlan was Vlan 2. I guess my question is why, all of the sudden, has the switchport configuration that works throughout the rest of our network (100+ APs) stopped working on just these three APs. Note: I have connected these APs to other switches and the issue still occurs.


  • 4.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted Mar 20, 2021 11:52 AM

    Hi,

    So what you have to do is the following:

    Default switchport configuration for all APs is

    Administrative Mode: Access
    Access: Vlan 50 (though i would suggest you to change this VLAN to another VLAN since Students use this VLAN).

    On the controller you have to configure VLAN2,50,XYZ  (XYZ - VLANID for the Guest).

    Then you go on each SSID Profiles and configure each VLAN on the SSID Part.
    Staff SSID: VLAN 2
    Student SSID: VLAN 50
    Guest SSID: VLAN XYZ

    Depending which ArubaOS you are using (if Aruba OS6.x or Aruba OS8.x) there are different paths/ways to configure the SSID having VLANs.



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    Shpat
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  • 5.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted 30 days ago
    This is greatly appreciated. In all honesty, I am going to need some assistance from an Aruba engineer to burrow down into these settings, but at least I know where to look now.

    Our controller is running OS 8.2.X.

    It sounds like we need to create a *new* management Vlan specifically for the purpose of passing the other Vlans to the APs and then configure the SSID settings to broadcast the Vlans that are made available by the management Vlan.

    My last question (maybe): I thought trunk ports were mostly used to connect Vlans across switches. Is there any reason why a switchport an AP is connected to would need to be configured as a trunk port?

    Thank you again for all of your time and all of your help.


  • 6.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted 30 days ago
    I just briefly/fast draw a simplified schema:



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    Shpat
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  • 7.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted 30 days ago
    switchport trunk encapsulation dot1q the connection is a success but the user is not getting IP from the external DHCP server.  IP address 192.168.1.15 255.255.255.0 secondary If you make that AP switch port as an access port for VLAN 205 and then connect a laptop wired to that port, Do you get the correct IP?
    TargetPayandBenefits
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    Salvador Willis
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  • 8.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted 30 days ago
    @shpat: Thank you so much for taking the time to create that diagram and to educate me on this issue.

    @salvadorwillis: Yes when I switch the port to access for Vlan 50 and plug in my laptop to ethernet, the laptop registers the correct IP.

    Very interesting development. I think I may have found a solution here. If I plug the AP into the console and interrupt the boot sequence, then run the "dhcp" command, save this setting with the "save" command, and then boot the device with "boot" (dhcp>save>boot). The device comes online and broadcasts with an IP from the proper vlan (vlan 50)! No need to adjust the switchport settings.

    Then, when I provision the device in the web gui (configuration>APs>Provision), the device loses the good IP (reverts back to stale IP from Vlan 2). I repeat the steps above and the device comes back online, provisioned with its new name and proper profile group. After manually saving the IP in the console for a second time, the AP seems to retrieve the proper IP and come online on subsequent reboots. This has worked with two of the affected APs so far.​​


  • 9.  RE: 205 Access Points Not Receiving Proper IP Address from Trunk Port

    Posted 29 days ago
    Think this might be the last word on this.

    Seems like these APs were all set to receive a static IP address (on the correct vlan [Vlan 50] in Configuration>AP>Provision. When I re-provisioned the APs I changed the static assignment to DHCP.

    I checked the DHCP lease table for addresses on Vlan-50. It didn't appear as though the IP address had been reassigned to another device on the network or that there would be any other reason why an IP conflict would be taking place. Maybe the lease had expired or couldn't be renewed on the AP. Not sure.

    All of the down APs are now up after following these steps:

    1. Plug AP into Console
    2. Interrupt boot
    3. Run dhcp
    4.Run save
    5. Run boot
    6. Provision AP on web gui (change Static IP to DHCP)
    7. Repeat steps 1-5.

    The AP should now come up and stay online.

    Thank you for all your suggestions.