Managing Access Points and Clusters
The Devicescape Reference AP shows current basic configuration settings for clustered access points (location, IP address, MAC address, status, and availability) and provides a way of navigating to the full configuration for specific APs if they are cluster members.
Standalone access points or those which are not members of this cluster do not show up in this listing. To configure standalone access points, you must discover or know the IP address of the access point and by using its IP address in a URL (http://IPAddressOfAccessPoint).
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Note
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The Devicescape Reference AP is not designed for multiple, simultaneous configuration changes. If you have a network that includes multiple access points, and more than one administrator is logged on to the Administration Web pages and making changes to the configuration, all access points in the cluster will stay in sync but there is no guarantee that all configuration changes specified by multiple users will be applied.
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The following topics are covered:
Navigating to Access Points Management
To view or edit information on access points in a cluster, click the Cluster > Access Points tab.
Understanding Clustering
A key feature of the Devicescape Reference AP is the ability to form a dynamic, configuration-aware group (called a cluster) with other Devicescape Reference APs in a network in the same subnet. Access points can participate in a self-organizing cluster which makes it easier for you to deploy, administer, and secure your wireless network. The cluster provides a single point of administration and lets you view the deployment of access points as a single wireless network rather than a series of separate wireless devices.
What is a Cluster?
A cluster is a group of access points which are coordinated as a single group via AP administration.
You can have multiple clusters on the same subnet if they have different cluster "names".
How Many APs Can a Cluster Support?
Currently, there is no hard limit on the number of APs in a cluster. Validation testing has verified a dozen or more supported on the same subnet. You can include as many APs as needed in a cluster at any one time.
What Kinds of APs Can Cluster Together?
A single Devicescape Reference AP can form a cluster with itself (a "cluster of one") and with other Devicescape Reference APs. In order to be members of the same cluster, access points must be:
- Compatible devices as designated by the manufacturer (APs must have compatible design features)
- Of the same radio configuration (all one-radio APs or all two-radio APs)
- Of the same band configuration (all single-band APs or all dual-band APs)
Having a mix of APs on the network does not adversely affect Devicescape Reference AP clustering in any way. However, it is helpful to understand the clustering behavior for administration purposes:
- Access points joining the cluster must be named the same. For more information on setting the cluster name, see Setting the Cluster Name.
- Access points of other brands will not join the cluster. These APs should be administered with their own associated Administration tools.
Which Settings are Shared as Part of the Cluster Configuration and Which Are Not?
Most configuration settings defined via the Devicescape Reference AP Administration Web pages will be propagated to cluster members as a part of the cluster configuration.
Settings Shared in the Cluster Configuration
The cluster configuration includes:
- Network name (SSID)
- Administrator password
- User accounts and authentication
- Wireless interface settings
- Guest Welcome screen settings
- Network Time Protocol (NTP) settings
- Radio settings
Only Mode, Channel, Fragmentation Threshold, RTS Threshold and Rate Sets are synchronized across the cluster. Beacon Interval, DTIM Period, Maximum Stations, and Transmit Power do not cluster.
When Channel Planning is enabled, the radio Channel is not synced across the cluster. See Stopping/Starting Automatic Channel Assignment
- Security settings
- MAC address filtering
Settings Not Shared by the Cluster
The few exceptions (settings not shared among clustered access points) are the following, most of which by nature must be unique:
- IP addresses
- MAC addresses
- Location descriptions
- Load Balancing settings
- WDS bridges
- Ethernet (Wired) Settings, including enabling or disabling Guest access
- Guest interface configuration
Settings that are not shared must be configured individually on the Administration pages for each access point. To get to the Administration pages for an access point that is a member of the current cluster, click on its IP Address link on the Cluster > Access Points page of the current AP.
Cluster Formation
A cluster is formed when the first AP is deployed with clustering enabled.
The AP attempt to rendezvous with an existing cluster.
If it is unable to locate any other APs on the subnet with the same cluster name, then it establishes a new cluster on its own.
Cluster Size and Membership
Currently, there is no hard limit on the number of APs in a cluster. Validation testing has verified a dozen or more supported on the same subnet. You can include as many APs as needed in a cluster at any one time.
Cluster membership is determined by:
Intra-Cluster Security
For purposes of ease-of-use, the clustering component is designed to let new devices join a cluster without strong authentication. However, communications of all data between access points in a cluster is protected against casual eavesdropping using Secure Sockets Layer (typically referred to as SSL). The assumption is that the private wired network to which the devices are connected is secure. Both the cluster configuration file and the user database are transmitted among access points using SSL.
Understanding Access Point Settings
The Access Points tab provides information about all access points in the cluster.
From this tab, you can view location descriptions, MAC addresses, IP addresses, enable (activate) or disable (deactivate) clustered access points, and remove access points from the cluster. You can also modify the location description for an access point.
The IP address links provide a way to navigate to configuration settings and data on an access point.
Stand-alone access points (those which are not members of the cluster) are not shown on this page.
The following table describes the access point settings and information display in detail.
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Field
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Description
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Location
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Description of where the access point is physically located.
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MAC Address
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Media Access Control ( MAC) address of the access point.
A MAC address is a permanent, unique hardware address for any device that represents an interface to the network. The MAC address is assigned by the manufacturer. You cannot change the MAC address. It is provided here for informational purposes as a unique identifier for the access point.
The address shown here is the MAC address for the bridge (br0). This is the address by which the AP is known externally to other networks.
To see MAC addresses for Guest and Internal interfaces on the AP, see the
Status > Interfaces tab.
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IP Address
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Specifies the IP address for the access point. Each IP address is a link to the Administration Web pages for that access point. You can use the links to navigate to the Administration Web pages for a specific access point. This is useful for viewing data on a specific access point to make sure a cluster member is picking up cluster configuration changes, to configure advanced settings on a particular access point, or to switch a standalone access point to cluster mode.
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Modifying the Location Description
To make modifications to the location description:
- Navigate to the Cluster > Access Points tab.
- Under the Clustering Options section, type the new location of the AP in the Location field.
- Click the Update button to apply the changes.
Setting the Cluster Name
To set the name of the cluster you want your AP to join, do the following:
- Navigate to the Cluster > Access Points tab.
- Under the Clustering Options section, type the new cluster name in the Cluster Name field.
- Click the Update button to apply the changes.
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Note
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If you want multiple APs to join a particular cluster, all these APs should have the same Cluster Name specified in the Cluster Name field. If the cluster name is different the AP will not be able to join the cluster.
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Stopping Clustering
To stop clustering and remove a particular access point from a cluster, do the following.
- Go to the Administration Web pages for the access point you want to remove from the cluster.
- Click the Cluster > Access Points tab.
- Click the Stop Clustering button to remove the access point from the Cluster.
The change will be reflected under Status for that access point; the access point will now show as standalone (instead of cluster).
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Note
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In some situations it is possible for the cluster to become out of sync. If after removing an access point from the cluster, the AP list still reflects the deleted AP or shows an incomplete display; refresh your browser. If you still experience problems, refer to the information on Cluster Recovery in Appendix B. Troubleshooting.
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Starting Clustering
To start clustering and add a particular access point to a cluster, do the following.
The Administration Web pages for the standalone access point are displayed.
- Click the Cluster > Access Points tab for the standalone access point.
- Click the Start Clustering button.
The access point is now a cluster member. It appears in the list of clustered access points on the Cluster > Access Points tabbed page.
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Note
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In some situations it is possible for the cluster to become out of sync. If after removing an access point from the cluster, the AP list still reflects the deleted AP or shows an incomplete display; refer to the information on Cluster Recovery in Appendix B. Troubleshooting.
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Navigating to Configuration Information for a Specific AP and Managing Standalone APs
In general, the Devicescape Reference AP is designed for central management of clustered access points. For access points in a cluster, all access points in the cluster reflect the same configuration. In this case, it does not matter which access point you actually connect to for administration.
There may be situations, however, when you want to view or manage information on a particular access point. For example, you might want to check status information such as client associations or events for an access point. Or you might want to configure and manage features on an access point that is running in standalone mode. In these cases, you can navigate to the Administration Web interface for individual access points by clicking the IP address links on the Access Points tab.
All clustered access points are shown on the Cluster > Access Points page. To navigate to clustered access points, you can simply click on the IP address for a specific cluster member shown in the list.
Navigating to an AP by Using its IP Address in a URL
You can also link to the Administration Web pages of a specific access point, by entering the IP address for that access point as a URL directly into a Web browser address bar in the following form:
http://IPAddressOfAccessPoint
where IPAddressOfAccessPoint is the address of the particular access point you want to monitor or configure.
