CAPsMAN v2 Overview

What it is

CAPsMAN is a feature that lets one RouterOS device manage the wireless settings of many access points from a single place.

The managing device is the CAPsMAN manager. Each managed access point is a CAP, which stands for controlled access point.

The manager holds the configuration and sends it to the CAPs. This replaces setting up every access point by hand, and it keeps SSIDs, security and channels consistent.

How it works

The CAP finds the manager, receives its settings, and the manager creates the wireless interfaces.

Two generations

There are two separate versions of CAPsMAN.

The two versions are not compatible. A CAP that runs the wifi driver cannot join a /caps-man manager, and the reverse is also true. In a mixed network you need a manager for each generation.

The parts of the system

CAPsMAN has four main parts.

• The manager, which holds the settings and the rules.
• The CAPs, which connect to the manager and run the radios.
• The configuration profiles, which describe the SSID, channel, security and datapath.
• The provisioning rules, which decide which configuration each CAP radio receives.

The next pages cover them in turn.

The life of a CAP

A CAP goes through these steps.

1. The CAP is switched on in CAP mode and looks for a manager.
2. The CAP and the manager set up a secure control connection.
3. The manager checks its provisioning rules against the radios of the CAP.
4. The manager sends the matching configuration.
5. The CAP creates the wireless interfaces and serves clients.

If the control link is lost, the CAP looks for a manager again.

Enabling the manager and a CAP

/interface wifi capsman set enabled=yes
/interface wifi cap set enabled=yes discovery-interfaces=ether1

• The first command turns on the manager function on the central router.
• The second command puts an access point into CAP mode, and discovery-interfaces lists the interfaces it uses to look for a manager.
• /interface wifi capsman remote-cap print on the manager lists the CAPs that have joined.

The same steps with the /caps-man menu (the version in the MTCEWE outline) look like this:

/caps-man manager set enabled=yes
/interface wireless cap set enabled=yes interfaces=wlan1 discovery-interfaces=ether1
/caps-man remote-cap print

The /caps-man menu holds the same parts as the wifi version: configuration, channel, datapath, security, rates, provisioning and access-list. For example, a configuration is created with /caps-man configuration add name=cfg1 ssid=office, and a rule hands it to new radios with /caps-man provisioning add action=create-dynamic-enabled master-configuration=cfg1.

A manager can also control its own local radios.

Benefits

CAPsMAN gives a number of advantages:

• one place to change the SSID, security and channels
• the same settings on every access point
• easier roaming, because the SSID and security match
• less work when you add a new access point

For small sites with one or two access points, the manager may add more complexity than it saves.

What the CAP radio becomes

When the manager provisions a radio, a dynamic interface appears on the manager for that radio. You can see it in the wireless interface list, and you can use it in other settings, for example to put it in a bridge.

Dynamic interfaces are created from the rules and the configuration. You change them by changing the configuration, not by editing the interface.

Where CAPsMAN fits

CAPsMAN is useful when:

• there are several access points that should share settings
• the access points are spread over a building or a campus
• you want roaming between access points
• you want to change a setting once and apply it everywhere