Hello Quirik
You are correct in that CAPWAP carries both user data as well as control data between the WLC and the APs, as seen in this lesson:
However, in this particular topology, we are not employing CAPWAP. We are manually creating VLANs that will be mapped to SSIDs on the APs. This of course is not very scalable, so for larger networks, the implementation as described in the linked lesson above should be used.
I hope this has been helpful!
Laz
Hi,
With regards to lesson:
Cisco Wireless LAN Controller (WLC) Basic Configuration
I have recreated the lab exactly. When connecting an AP, it does not seem to pair up.
When checking the AP, I see the following:
%Error opening flash:/update/info (No such file or directory)
ERROR: Image is not a valid IOS image archive.
Download image failed, notify controller!!! From:7.5.1.73 to 0.0.0.0, FailureCode:3
archive download: takes 48 seconds
., 1) 8 11:36:49.507: %CAPWAP-3-ERRORLOG: Retransmission count for packet exceeded max(CAPWAP_ECHO_REQUEST
*Mar 8 11:36:49.507: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to 192.168.10.100:5246
*Mar 8 11:36:49.507: %LWAPP-3-CLIENTERRORLOG: LWAPP LED Init: incorrect led state 255
*Mar 8 11:36:49.511: %LWAPP-3-CLIENTERRORLOG: Config load from flash failed. Initialising Cfg
*Mar 8 11:36:49.511: %CAPWAP-3-ERRORLOG: Failed to load configuration from flash. Resetting to default config
*Mar 8 11:36:49.523: %CAPWAP-3-ERRORLOG: capwap ifs: read error or timeout
*Mar 8 11:36:49.527: capwap_image_proc: problem extracting tar file
*Mar 8 11:36:49.527: %CAPWAP-3-ERRORLOG: Dropping dtls packet since session is not established. 192.168.10.100, 147E, 192.168.10.5, 8908, 0
*Mar 8 11:36:59.523: %CAPWAP-3-ERRORLOG: Go join a capwap controller
examining image...
*Mar 8 11:36:59.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 192.168.10.100 peer_port: 5246
*Mar 8 11:36:59.499: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: 192.168.10.100 peer_port: 5246
*Mar 8 11:36:59.499: %CAPWAP-5-SENDJOIN: sending Join Request to 192.168.10.100perform archive download capwap:/ap1g2 tar file
*Mar 8 11:36:59.503: %CAPWAP-6-AP_IMG_DWNLD: Required image not found on AP. Downloading image from Controller.
logging facility kern
From what I read, the correct IOS image for the AP is missing on the WLC?
Hello Jaco
Yes, the underlying problem is that the AP is trying to receive an image that is either invalid or nonexistent. There may be various reasons for this including your WLC version and your AP. Make sure that your WLC platform and version are compatible with your AP model. Here is an example of a similar failure due to the version of the controller:
You may find this compatibility matrix useful in determining if your specific hardware is compatible.
Let us know how you get along and if there is anything else that we can help you with.
I hope this has been helpful!
Laz
There is an interface that gets created using the wizard gigabit0 and I donât see any physical interface gigabit0 this interface has vrf Mgmt-intf. I created a management vlan and associated that vlan to a physical interface te0/0/0 but I can reach the gateway and the wlc is connected via Layer2 to a router where the gateway vlan is defined.
I was wondering if anyone in this forum is running a 9800 wlc
Thanks,
Juan
Hello Juan
When configuring a Cisco 9800 WLC, the interface GigabitEthernet0 youâre referring to is actually a virtual interface, often referred to as the âout-of-bandâ management interface. This virtual interface is used for system management and is usually tied to the Management VRF (in your case, itâs called âMgmt-intfâ).
You cannot directly assign a physical interface to this GigabitEthernet0 interface. Instead, your physical interface (te0/0/0 in your case) connects to the network switch, and then you associate this connection with the VLAN that you have configured for management purposes.
Once you configure that switch port, the VLAN on the WLC, and the router as the default gateway, you should be able to reach the default gateway from your WLC. If not, there may be other issues concerning the configuration of the rest of your network. Let us know how you get along so we can see how we can help you further.
I hope this has been helpful!
Laz
Hello All,
I am having a problem with associating a Cisco 9166I AP with a 9800 WLC. One of the document that I found this issue could be the AP is in Meraki Management mode and the AP need to perform a migration procedure. I donât have a support contract for the AP and I canât open a Cisco TAC case. I would appreciate if you have ran into this issue or know how to perform a migration procedure.
Thank you
Juan
Hello Juan
Based on the information you have given us, it is not possible to determine the reason for the problem you are facing. However, if you have determined the problem to be that the AP is indeed in Meraki Management mode, then you must perform the migration procedure as you suggested. There are some requirements in order for this to be successful. First of all, here is some info from the datasheet of the product concerning migration:
Included are step-by-step instructions to achieve the migration.
Secondly, here you can see that if you want to migrate from Meraki to the 9800 WLC (DNA center administration), you must have sufficient licensing for the migration. You will have to check on the Meraki cloud subscription that manages that particular AP, if the appropriate licensing is compliant for a migration. If not, you may need to purchase the appropriate license.
This information should be enough to get you started on the migration process. Let us know how you get along and if you need any further assistance.
I hope this has been helpful!
Laz
Hello Laz,
Thank you so much for taking the time to answer my question. Your information that you provided is really good and Iâm sure will help me on the problem.
Again, I appreciate your response and have a great day.
Juan
There are a lot of commands to learn in this section. Do you have any suggestions for best practices to learn these, including the amount of time to spend, in the context of the many topics covered in your CCNA curriculum?
Hello Jim
For the purposes of the CCNA certification, it is not necessary to memorize each and every command. However, what I would suggest is to perform the lab a couple of times so that you get an idea of the steps and processes involved in delivering a basic configuration of a WLC and any connected switch. Once you are proficient in understanding the processes and steps involved, I believe you will have covered the primary content necessary for the CCNA exam.
From a strictly experiential point of view, if you want to be able to set up a WLC from scratch in a production environment, then you will probably have to go over various pieces of Cisco documentation to go beyond what is described in the lesson. But there you have reference material available for you, and you donât really need to memorize the process. Does that make sense?
I hope this has been helpful!
Laz
Laz,
Iâll lookout for a lab to run the basic configurations. Thanks.
Does anyone understand how this âauthbypassâ feature works in the L3 Webauth â or what problem it solves?
It sounds like MAB but what is it doing in Webauth where the whole idea is for the client to enter credentials?
Is this feature possibly related to the L2 âMAC Filteringâ feature in the WLAN setup?
Hello Sandro
The âauthbypassâ feature in Layer 3 Web Authentication, is a feature that allows certain users or devices to bypass the usual authentication process. This can be useful in situations where certain devices that donât correspond to a specific user (like printers or IoT devices) cannot interact with the web-based login page to input credentials.
For Authbypass, the network administrator identifies the MAC address of the device that should bypass authentication. This MAC address is then added to a whitelist on the network controller.
When this device attempts to connect to the network, the controller checks its MAC address against the whitelist. If the deviceâs MAC address is on the whitelist, it is allowed to bypass the usual web-based authentication process and connect directly to the network.
Remember that while this feature can be convenient, it also poses a security risk. If a device with a whitelisted MAC address is lost or stolen, or if a whitelisted MAC is learned and spoofed, someone could potentially connect to your network without having to authenticate. Therefore, itâs important to manage your whitelist carefully and remove devices from it when they are no longer needed.
I hope this has been helpful!
Laz
Hello Lazarus,
Thanks for the follow up.
I eventually received some clarification on this issue from the Cisco community over the weekend.
Evidently the authbypass feature is not supported on WLCs.
Here is the link that I was provided in the post:
Knowing all this it begs the question why this option is even present at all in the WLC OS.
But, all that being said - this feature sounds exactly like MAB.
So if my understanding of authentication on the WLC is correct, it goes something like this:
This is why having the authbypass feature in Webauth made no sense to me at first glanceâŚ
Hello Sandro
Thanks for sharing the solution that you have discovered, and for sharing the documentation. Indeed, on the WLC based on the Catalyst 9800 series devices, the authbypass feature is not supported. Specifically, itâs not supported on the wireless component of the operation of the device.
However, as mentioned in the documentation you provided:
Authbypass: The controller uses the MAC address as the client identity and validates this with the authentication server that has a database of client MAC addresses that are allowed network access.
The feature itself is functional on wired connections as described above, and it is indeed useful for situations where we connect devices such as printers, IP cameras, and IoT devices.
As for your comparison of the authbypass feature to MAB, they do have similarities, but they are not exactly the same. MAB is a fallback method that allows devices without 802.1x capability to connect to the network, while the authbypass feature (where it is supported) bypasses the authentication process entirely.
I hope this has been helpful!
Laz
Thank Lazarus, that helps clear things up for me.
Hello, everyone.
What is the difference between Conditional Web Redirect and Splash Page Web Redirect when configuring WebAuth?
Does the second option redirect you all the time while the first one only does it if a certain condition is true?
Thank you.
David
Hello David
Itâs essentially what you said. The Splash page redirect causes the user to be redirected to a specific web page after the 802.1X authentication has been completed. After the redirect, the user has full access.
The Conditional web redirect conditionally redirects a user to a particular web page after successful 802.1X authentication. The redirect page and the conditions under which the redirect happens are specified on the RADIUS server.
More detailed information can be found at this Cisco documentation, where both are described in detail:
I hope this has been helpful!
Laz
Hi, Can explain what it refers to the below statement from the lesson.
The mobility and RF group names are for WLCs that want to work together. WLCs with the same mobility group name support client roaming and redundancy between WLCs. If you use the same RF group name, WLCs can do Radio Resource Management (RRM) calculations for the entire group.
Hello Gowtham.
Before we explain what mobility and RF groups are, we need to clarify certain things. Iâll start with RF Groups
RRM
Imagine that we have a building that has several APs that are managed by a WLC.
A really cool thing that WLCs can do is provide RRM (Radio-Resource Management). In other words, the WLC can tell the APs how much signal they should transmit to provide optimal coverage for the building, to ensure that there is a decent overlap, and to prevent things like interference.
Another thing that RRM can do is provide coverage hole detection and self-healing. In other words, if an AP goes down for whatever reason
RF Groups
If you have APs managed by multiple WLCs, the WLCs will have to exchange information and coordinate RRM together. For simplicity, the WLCs exchange information and one of them eventually becomes the leader who controls the radios based off the provided information 
In order for this to happen, the WLCs need to be part of the same RF group. If they arenât, they wonât work and coordinate this RRM information together.
RF Groups are more of a CCNP topic so Iâve only provided a high overview for you here, assuming that youâre studying for the CCNA?
What is roaming?
Roaming occurs when a wireless client disconnects from one AP and connects to another as a result of physical movement.
Imagine that youâre in a building that has wireless coverage that is provided by 2 APs. AP-1 covers the left side of the building while AP-2 covers the right side of the building.
If you are located on the left side of the building, you will associate to AP-1. However, what happens if you move around the building? If you decide to walk around the building and you happen to move further to the right
The goal here is to associate and be connected to an AP that is simply providing the better and more reliable signal.
Mobility Groups
Disconnecting from one AP and connecting to another isnât as simple as weâd like it to be unfortunately. When this happens, the client has to fully re-authenticate. During this process, the client could encounter a small window of downtime. This might be fine if youâre doing things like browsing the web but if youâre running any real-time applications (voice call/video), even a small downtime could cause noticable disruption.
A simple home authentication (WPA Personal) where you only enter the WiFi password happens pretty quickly and the client doesnât really notice any large downtime. However, if you work in an Enterprise where you use 802.1x and a RADIUS server for authentication (WPA Enterprise), this process could be significantly longer considering that the RADIUS server is also involved in this process.
So how can we improve this? How can we make the roaming as fast and as seamless as possible with minimal downtime? What weâre about to discuss is more of a CCNP/IE-level thing, so Iâll do my best to keep it as simple as possible.
Weâll use this topology as an example. The main point here is that both APs are managed by the same WLC for simplicity.
We know that if the client disconnects from AP-1 and connects to AP-2, depending on how our authentication and such is setup, downtime could be introduced.
For this reason, fast-roaming technologies were introduced. In simple terms, if you enable a fast-roaming technology like 802.11r or CCKM, the WLC will preserve/store a portion of the clientâs original authentication and session information and will provide it to AP-2 once the client roams. This will allow the client and the AP to effectively âskipâ a part of the authentication process which will make it faster.
The real process behind this can be hard to understand, especially at the CCNA level so all of this is an oversimplification.
This process becomes even more complicated if the APs are managed by different WLCs
In this case, if the client roams and disconnects from AP-1 that is connected to WLC-1, WLC-1 will need to send the preserved authentication and session information to WLC-2 that manages AP-2 to make fast roaming possible.
This is where mobility groups come into play. If two controllers are part of the same mobility group (for example, lets call it NETWORKLESSONS) - they will exchange this information and thus we will have seamless roaming. If they arenât a part of the same mobility group then they wonât exchange this information and we wonât have fast roaming.
There is a lot more to this including mobility lists/domains and such so if you want to know more, you should read these documents
If youâre studying for the CCNA and you find mobility groups hard to understand then I wouldnât really bother covering them until later in your studies (CCNP and so on) as the CCNA doesnât require you to know them. Thereâs an entire topic dedicated to roaming and mobility groups on the CCNP ENCOR exam.
Let me know if you need further help!
David
