The CoA bounce host port command terminates a session and bounces the port (initiates a link down event followed by a link
up event). The AAA server sends the request in a standard CoA-Request message with the following VSA:
Because this command is session-oriented, it must be accompanied by one or more of the session identification attributes
described in the “Session Identification” section. If the session cannot be located, the device returns a CoA-NAK message with the “Session Context Not Found” error-code
attribute. If the session is located, the device disables the hosting port for a period of ten seconds, reenables it (port
bounce), and returns a CoA-ACK.
If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device when the request
is re-sent from the client. If the device fails after returning a CoA-ACK message to the client but before the operation is
complete, the operation is restarted on the new active device.
The CoA bounce port command is useful as a last resort when an endpoint needs to acquire a new IP address after a change
in authorization and this is the only way to indicate to the endpoint to restart the DHCP process. This can occur when there
is a VLAN change and the endpoint is a device, such as a printer, that does not have a mechanism to detect a change on this
authentication port. This command can cause a link flap on an authentication port, which triggers DHCP renegotiation from
one or more hosts connected to this port.