Cisco 500 Series - Page 300

Spanning Tree
STP Status and Global Settings
Cisco 500 Series Managed Switch Administration Guide 298
15
• STP Operation Mode—Select an STP mode.
• BPDU Handling—Select how Bridge Protocol Data Unit (BPDU) packets are
managed when STP is disabled on the port or the device. BPDUs are used
to transmit spanning tree information.
- Filtering—Filters BPDU packets when Spanning Tree is disabled on an
interface.
- Flooding—Floods BPDU packets when Spanning Tree is disabled on an
interface.
• Path Cost Default Values—Selects the method used to assign default path
costs to the STP ports. The default path cost assigned to an interface varies
according to the selected method.
- Short—Specifies the range 1 through 65,535 for port path costs.
- Long—Specifies the range 1 through 200,000,000 for port path costs.
Bridge Settings:
• Priority—Sets the bridge priority value. After exchanging BPDUs, the device
with the lowest priority becomes the Root Bridge. In the case that all bridges
use the same priority, then their MAC addresses are used to determine the
Root Bridge. The bridge priority value is provided in increments of 4096. For
example, 4096, 8192, 12288, and so on.
• Hello Time—Set the interval (in seconds) that a Root Bridge waits between
configuration messages.
• Max Age—Set the interval (in seconds) that the device can wait without
receiving a configuration message, before attempting to redefine its own
configuration.
• Forward Delay—Set the interval (in seconds) that a bridge remains in a
learning state before forwarding packets. For more information, refer to
Spanning Tree Interface Settings.
Designated Root:
• Bridge ID—The bridge priority concatenated with the MAC address of the
device.
• Root Bridge ID—The Root Bridge priority concatenated with the MAC
address of the Root Bridge.
• Root Port—The port that offers the lowest cost path from this bridge to the
Root Bridge. (This is significant when the bridge is not the root.)