Wednesday, 10 February 2016

Understanding and configuration of cluster mode on the EAP120 V1.0 (Firmware 20141107), EAP220 V1.0(Firmware 20150105)

Note:
1. This article only applies to EAP120 V1.0 (Firmware 20141107), EAP220 V1.0(Firmware 20150105)
2.EAP120 V1.0 (Firmware 20141107), EAP220 V1.0(Firmware 20150105) cannot be managed by EAP controller.
 
Part1: Some knowledge introduction
What’s a Cluster?
EAP120 V1.0 is initially released with the firmware 20141107. This firmware adopts two particular management modes called Cluster mode and Standalone mode.
Cluster mode is the default mode. Under Cluster mode, once powered on, all EAPs will negotiate with each other in the same LAN and one of them will be elected master EAP, while the others will become member/slave EAPs, as shown in Figure 1. In this way the EAPs in the same subnet automatically form a group called cluster. All member EAPs in a cluster can synchronize their configurations with the master EAP.

Figure 1
Note: A cluster consists of up to 24 EAPs (including the master EAP).
 
The principles of forming a cluster:
1. The selection of the master EAP is based on the device’s uptime. For example, 10 EAPs are powered on at almost the same time. However their uptime is still slightly different. The one with the longest uptime will be elected themaster EAP of this cluster. If the current master EAP leaves the cluster, the member EAPs still keep the current configuration and will restart a selection based on the same principle.
2. A Cluster is defined by its Cluster Name. The default cluster name of all EAPs is TP-LINK, thus EAPs in default settings will automatically form a cluster. Different clusters are distinguished by their cluster names. By changing cluster name, users can set up multiple clusters in the same LAN. Clusters of different cluster names can have different configurations.

Figure 2
Users can change Cluster Name under Cluster tab via the master’s web interface. Once a new Cluster Nameis set and saved, all the EAPs in the cluster will adopt the new cluster name synchronously.
 
How to manage a cluster?
A cluster is managed as an entirety.
Once a cluster is formed, the master EAP becomes the central management point of the cluster. When users attempting to access the web interface of any one of the member EAP, they will be redirected to the master’s web interface. That means the master’s web interface is the only management entry for the whole cluster.
      Users manage all EAPs in a cluster synchronously via the master’s web interface. Every setting you configured on the master will be synchronized on the member EAPs in the same cluster, as shown below in Figure 3.

Figure 3
 
Typical topology
      A typical topology of the EAP products is shown in Figure 4.
Typically, a PoE switch is used to provide power for each EAP. Otherwise, each EAP must be powered with a power adapter individually, which is not convenient for massive deployment.
Once the LAN port is connected, the EAP will try obtaining an IP address via DHCP. If there is no DHCP server available in LAN, the EAP will assign itself with the address 192.168.0.254, and there will be IP conflict in below scenario. So a DHCP server is mandatory in the local network to assign IP addresses to the EAPs.
A gateway router acts as the DHCP server in the following examples.

Figure 4
 
Part2: Configure the cluster via Quick Setup
Log in to the masters’ web interface
      Users can log in the master EAP’s web interface either via Ethernet or via wireless.

Figure 5
-      Wireless login
1.    Once the master is elected, all EAPs will broadcast the same SSID, named TP-LINK_XGHz_XXXXXX without security. Connect the admin host to this SSID.
2.    Ensure the admin host obtains IP address/gateway/DNS via DHCP successfully.
3.    Open a web browser and enter the domain name http://tplinkeap.net to log in. The default user name and password are both admin. Then you will be redirect to the master’s login page.
-      Ethernet login
1.    Connect the admin host to the same LAN with the EAPs. Ensure the admin host is set to obtain IP address via DHCP automatically.
2.    Log in the DHCP server (which is Router’s web interface in figure 5) to find out the IP addresses of the EAPs based on the hostname EAPXXX-XX-XX-XX-XX-XX.

Figure 6
3.    Open a web browser and enter any one of these IP addresses to log in. The default user name and password are bothadmin. Whichever IP address you type in, you will be redirect to the master’s login page.
Note:
- Wireless login supports log in via domain name and IP address.
- Ethernet login only supports log in via IP address.
- The default username/password is admin/admin. After the first login it requires to change the default password for better security.
 
Step by step configuration via Quick Setup
In the master’s web interface, there are six main tabs: Quick SetupClusterWirelessMonitoringManagement, and System. Most settings within these menus are applied to all the EAPs in the cluster.
At the first login, the Quick Setup wizard will launch. Quick Setup is a convenient way for basic settings for most users. Here we introduce how to use Quick Setup to configure the EAPs.

Figure 7
Step1: Select a Region and click Next. Ensure you select a correct region to comply with local regulations.
Step2: Configure wireless settings. Create the SSID and Password for your Wi-Fi. Click Next.
Step3: Confirm the settings in the summary page, click Save to apply the settings and wait for the settings to take effect. The above configurations on the master EAP will be synchronized to all the other EAPs automatically.
Once the settings take effect, the SSID will be changed to the new SSID you entered. Thus wireless connection will drop and wireless clients must reconnect to the new SSID.
Now the new SSID should appears, which means the settings have taken effect.If you need advanced settings, you can log in the web interface again to configure via the other 5 tabs: ClusterWirelessMonitoringManagement, andSystem.
 
Note:
As described above, by default all the EAPs in the cluster will be synchronized with the same configuration. Yet the Master’s web UI also allows users to configure every EAP individually with independent settings.
To configure a specific EAP, navigate to Cluster tab --> AP list, and click the Edit button at the target column. Then a new box will show, where you can configure the selected EAP’s settings separately.
 
Figure 8
 
 
Part3: Standalone mode
In Cluster tab click the Trash button to remove a specific EAP from the cluster. The management mode of the removed EAP will switch to standalone mode.
An EAP of standalone mode works independently and won’t be synchronized with the Master’s configuration any more. Thus users must login the standalone EAP’s web interface via its own IP address to configure it individually.

Figure 10
The web UI of standalone mode is different from cluster mode. The Quick Setup tab and Cluster tab are disappeared. Users can switch the EAP back to cluster mode in Network tab.

Figure 11