S350 Series 24-Port (PoE+) and 48-Port Gigabit Ethernet Smart Managed Pro Switches 
 Configuration Examples User Manual349
6.  On the RADIUS Server Configuration page, configure a RADIUS server with the following 
settings:
• Server Address. 192.168.10.23
• Secret Configured. Yes
•
Secret. secret123
• Active. Primary
For more information, see 
Manage the RADIUS Settings on page  211.
7.  Click the Add button.
8.  On the 
Authentication List page, configure the default list to use RADIUS as the first 
authentication method. (See 
Configure Authentication Lists on page  223.)
This example enables 802.1X-based port security on the switch and prompts the hosts 
connected on ports g5-g8 for an 802.1X-based authentication. The switch passes the 
authentication information to the configured RADIUS server
.
Multiple Spanning Tree Protocol
Spanning Tree Protocol (STP) runs on bridged networks to help eliminate loops. If a bridge 
loop occurs, the network can become flooded with traffic. IEEE 802.1s Multiple Spanning 
Tree Protocol (MSTP) supports multiple instances of spanning tree to efficiently channel 
VLAN traffic over different interfaces. Each instance of the spanning tree behaves in the 
manner specified in IEEE 802.1w, Rapid Spanning Tree, with slight modifications in the 
working but not the end effect (chief among the effects is the rapid transitioning of the port to 
the forwarding state). 
The difference between the RSTP and the traditional STP (IEEE 802.1D) is the ability to 
configure and recognize full-duplex connectivity and ports that are connected to end stations, 
resulting in rapid transitioning of the port to the Forwarding state and the suppression of 
T
opology Change Notification. 
These features are represented by the parameters 
pointtopoint and edgeport. MSTP is compatible to both RSTP and STP. It behaves in a way 
that is appropriate for STP and RSTP bridges. 
An MSTP bridge can be configured to behave entirely as a RSTP bridge or an STP bridge. 
So, an IEEE 802.1s bridge inherently also supports IEEE 802.1w and IEEE 802.1D.
The MSTP algorithm and protocol provide simple and full connectivity for frames assigned to 
any VLAN throughout a bridged LAN comprising arbitrarily interconnected networking 
devices, each operating MSTP, STP
, or RSTP. MSTP allows frames assigned to different 
VLANs to follow separate paths, each based on an independent Multiple Spanning Tree 
Instance (MSTI), within Multiple Spanning Tree (MST) regions composed of LANs and or 
MSTP bridges. These regions and the other bridges and LANs are connected into a single 
Common Spanning Tree (CST). (IEEE DRAFT P802.1s/D13)
MSTP connects all bridges and LANs with a single Common and Internal Spanning Tree 
(CIST). 
The CIST supports the automatic determination of each MST region, choosing its 
maximum possible extent. 
The connectivity calculated for the CIST provides the CST for