Configuring HABP

The HW Authentication Bypass Protocol (HABP) is intended to enable the downstream network devices of an access device to bypass 802.1X authentication and MAC authentication configured on the access device.

As shown in Figure 75, 802.1X authenticator Switch A has two switches attached to it: Switch B and Switch C. On Switch A, 802.1X authentication is enabled globally and on the ports connecting the downstream network devices. The end-user devices (the supplicants) run the 802.1X client software for 802.1X authentication.

The communication between Switch B and Switch D, where the 802.1X client is not supported (which is typical of network devices), will fail because they cannot pass 802.1X authentication and their packets will be blocked on Switch A. To allow the two switches to communicate, you can use HABP.

HABP is a link layer protocol that works above the MAC layer. HABP is built on the client-server model. Generally, the HABP server is enabled on the authentication device that is configured with 802.1X or MAC authentication (such as Switch A in Figure 75), and the attached switches function as the HABP clients (such as Switch B through Switch E in Figure 75). No device can function as both an HABP server and a client at the same time.

Typically, the HABP server sends HABP requests to all its clients periodically to collect their MAC addresses, and the clients respond to the requests. After the server learns the MAC addresses of all the clients, it registers the MAC addresses as HABP entries. Then, link layer frames exchanged between the clients can bypass the 802.1X authentication on ports of the server without affecting the normal operation of the whole network.

All HABP packets must travel in a specific VLAN. Communication between the HABP server and HABP clients is implemented through this specific VLAN.