Chapter 11 Spanning Tree Protocol

Table 27 RSTP: Configuration (continued)

LABEL

DESCRIPTION

 

 

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)

Port

This field displays the port number.

 

 

*

Settings in this row apply to all ports.

 

Use this row only if you want to make some settings the same for all ports. Use this

 

row first to set the common settings and then make adjustments on a port-by-port

 

basis.

 

Note: Changes in this row are copied to all the ports as soon as you

 

make them.

Active

Select this check box to activate RSTP on this port.

 

 

Priority

Configure the priority for each port here.

 

Priority decides which port should be disabled when more than one port forms a

 

loop in a switch. Ports with a higher priority numeric value are disabled first. The

 

allowed range is between 0 and 255 and the default value is 128.

Path Cost

Path cost is the cost of transmitting a frame on to a LAN through that port. It is

 

assigned according to the speed of the bridge. The slower the media, the higher

 

the cost - see Table 24 on page 104 for more information.

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 reset the fields.

11.4 Rapid Spanning Tree Protocol Status

Click Advanced Application, Spanning Tree Protocol in the navigation panel to display the status screen as shown next. See Section 11.1 on page 103 for more information on RSTP.

Note: This screen is only available after you activate RSTP on the switch.

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GS-3012/GS-3012F User’s Guide