Siemens SCALANCE X-300 Configuration Manual page 136

Configuration using Web Based Management and Command Line Interface
4.5 The Switch menu
DHCP Option 82
If you enable DHCP option 82, the IE Switch adds an "Option 82" field to DHCP queries
before the queries are forwarded to the DHCP server (assuming the received query has
such a field). The "Option 82" field contains information about the localization of the new
client in the network.
As the device identifier of the IE switch, you can set either the IP address or the MAC
address. The device identifier and the addresses of one or more DHCP servers can be
configured in the DHCP Relay Agent Configuration menu item.
VLAN 0 Aware Mode (SCALANCE X-300 only)
If you enable VLAN 0 Aware mode, the VLAN tags of frames with VLAN-ID 0 will not be
modified or deleted.
This setting only influences ports that are untagged members in VLAN-ID 1.
If the VLAN 0 Aware mode is enabled, you cannot create any VLAN configurations. To
change the VLAN-IDs of the ports, you need to disable this option.
Spanning Tree Protocol
In the lower part of the screen, you can enable or disable the following redundancy methods:
STP
STP (Spanning Tree Protocol) is a method with which loops are prevented in redundant
network structures.
If you enable STP, you enable the spanning tree functionality.
Typical reconfiguration times with spanning tree are between 20 and 30 seconds.
RSTP
RSTP (Rapid Spanning Tree Protocol) is a further development of the Spanning Tree
Protocol. The aim of RSTP is to achieve a faster reconfiguration time in the seconds range.
If you enable RSTP, you enable the rapid spanning tree functionality.
If a spanning tree frame is detected at a port, this port reverts from RSTP to STP.
MSTP (SCALANCE X-300 and SCALANCE X408 only)
MSTP (Multiple Spanning Tree Protocol) is a further development of the Rapid Spanning
Tree Protocol. The aim of MSTP is to operate independent RSTP instances within different
VLANs on an IE switch.
If you enable MSTP, you enable the multiple spanning tree functionality.
Note
When using (R/M)STP, loops involving duplication of frames or frames being overtaken may
occur briefly. If this is not acceptable for your application, use other alternative redundancy
methods such as HRP or the slower standard spanning tree.
136
Configuration Manual, 10/2014, C79000-G8976-C187-22
SCALANCE X-300 / X-400