Dell PowerConnect 3248 Manual page 26

26 Addendum to the 32 48 and 5 224 User 's Guides
• Root Port — Specifies the port number on the switch that is closest to
the root. The switch communicates with the root device through this
port. If there is no root port, the switch was accepted as the root device
of the Spanning Tree network.
• Root Path Cost — Identifies the path cost from the root port on the
switch to the root device.
• Configuration Changes — Specifies the number of times the
Spanning Tree has been reconfigured.
• Last Topology Change — Identifies the time since the Spanning Tree
was last reconfigured.
From the Bridge Settings page, under Attributes, you can configure the
following Spanning Tree parameters:
• Spanning Tree State — Enables or disables the Spanning Tree. If you
enable the Spanning Tree, you must complete the other fields.
(Default: Enabled)
• Spanning Tree Type — Specifies the type of Spanning Tree Protocol
used on the switch: (Default: RSTP)
– STP: Spanning Tree Protocol (IEEE 802.1D).
STP creates one Spanning Tree instance for the entire network. If
multiple VLANs are implemented on a network, the path between
specific VLAN members may be inadvertently disabled to prevent
network loops, thus isolating group members.
NOTICE: When the STP option is selected, the switch uses RSTP set to STP
forced-compatibility mode.
– RSTP: Rapid Spanning Tree (IEEE 802.1w).
RSTP supports connections to either STP or RSTP nodes by
monitoring the incoming protocol messages and dynamically
adjusting the type of protocol messages the RSTP node transmits,
as described below:
– STP Mode – If the switch receives an 802.1D BPDU (such as,
STP BPDU) after a port's migration delay timer expires, the
switch assumes it is connected to an 802.1D bridge and starts
using only 802.1D BPDUs.