Chapter 11 Spanning Tree Protocol

The following table describes the labels in this screen.

Table 25 Advanced Application > Spanning Tree Protocol > MSTP

LABEL

DESCRIPTION

Status

Click Status to display the MSTP Status screen (see Figure 48 on page 106).

 

 

Active

Select this check box to activate MSTP on the Switch. Clear this check box to

 

disable MSTP on the Switch.

 

 

Hello Time

This is the time interval in seconds between BPDU (Bridge Protocol Data Units)

 

configuration message generations by the root switch. The allowed range is 1 to

 

10 seconds.

 

 

MAX Age

This is the maximum time (in seconds) a switch can wait without receiving a BPDU

 

before attempting to reconfigure. All switch ports (except for designated ports)

 

should receive BPDUs at regular intervals. Any port that ages out STP information

 

(provided in the last BPDU) becomes the designated port for the attached LAN. If it

 

is a root port, a new root port is selected from among the Switch ports attached to

 

the network. The allowed range is 6 to 40 seconds.

 

 

Forwarding Delay

This is the maximum time (in seconds) a switch will wait before changing states.

 

This delay is required because every switch must receive information about

 

topology changes before it starts to forward frames. In addition, each port needs

 

time to listen for conflicting information that would make it return to a blocking

 

state; otherwise, temporary data loops might result. The allowed range is 4 to 30

 

seconds. As a general rule:

 

Note: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1)

 

 

Maximum hops

Enter the number of hops (between 1 and 255) in an MSTP region before the

 

BPDU is discarded and the port information is aged.

 

 

Configuration

Enter a descriptive name (up to 32 characters) of an MST region.

Name

 

 

 

Revision Number

Enter a number to identify a region’s configuration. Devices must have the same

 

revision number to belong to the same region.

 

 

Apply

Click Apply to save your changes to the Switch’s run-time memory. The Switch

 

loses these changes if it is turned off or loses power, so use the Save link on the

 

top navigation panel to save your changes to the non-volatile memory when you

 

are done configuring.

 

 

Cancel

Click Cancel to begin configuring this screen afresh.

 

 

Instance

Use this section to configure MSTI (Multiple Spanning Tree Instance) settings.

 

 

Instance

Enter the number you want to use to identify this MST instance on the Switch. The

 

Switch supports instance numbers 0-16.

 

 

Bridge Priority

Set the priority of the Switch for the specific spanning tree instance. The lower the

 

number, the more likely the Switch will be chosen as the root bridge within the

 

spanning tree instance.

 

Enter priority values between 0 and 61440 in increments of 4096 (thus valid values

 

are 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960,

 

45056, 49152, 53248, 57344 and 61440).

 

 

VLAN Range

Enter the start of the VLAN ID range that you want to add or remove from the

 

VLAN range edit area in the Start field. Enter the end of the VLAN ID range that

 

you want to add or remove from the VLAN range edit area in the End field.

 

Next click:

 

• Add - to add this range of VLAN(s) to be mapped to the MST instance.

 

• Remove - to remove this range of VLAN(s) from being mapped to the MST

 

instance.

 

• Clear - to remove all VLAN(s) from being mapped to this MST instance.

 

 

Enabled VLAN(s)

This field displays which VLAN(s) are mapped to this MST instance.

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ES-2024 Series User’s Guide