80 CHAPTER 10: MAKING Y OUR N ETWORK S ECUREFigure 18 Network Login OperationWhen the client device and RADIUS server have exchangedauthentication information, the Switch receives either an authenticationsucceeded or failed message from the server, and then configures theport to forward or filter traffic as appropriate. If access is granted, theSpanning Tree Protocol places the port into the forwarding state and theclient device can obtain an IP address.If possible, when a port is configured for Network Login, it should also beconfigured to be a Spanning Tree Protocol (STP) edge port. This minimizesthe delay before STP places the port into the forwarding state.For further information about RADIUS, see “What is RADIUS?” onpage 83.ImportantConsiderationsThis section contains some important considerations when using NetworkLogin on your Switch.■ Before you enable Network Login you must ensure that:■ RADIUS has been configured on the Switch.■ The RADIUS server in your network is operational.■ If the RADIUS server fails or is unavailable, client devices will be unableto access the network.Network Access Server(Switch 3848)Network Access Client(Client Device)AuthenticationInformationAuthenticationInformationRADIUS Server
