Cisco network engineer Note: Switch STP Configuration

Switch STP Configuration

The value range of the Spanning Tree priority is 0 ~ 61440, increment is 4096, its valid value is ,......, 61440. The smaller the priority value, the higher the priority. 0 is the highest, and 61440 is the lowest.

When oneVswitchWhen the root port or blocked port of receives the inferior BPDUs package, it indicates that the indirect link from the switch to the root bridge is faulty, and the link between the switch and the root bridge may fail. The blocked port is converted to the forwarding working state to fix this fault. Before the blocked port is converted to the forwarding working state, you need to wait for a maximum Spanning Tree survival time, the BackboneFast function is to make the blocked port no longer wait for this period of time, but directly switch the port from listening and learning status to forwarding status. This conversion task takes about 30 s, this improves the convergence speed when the indirect link fails.

UplinkFast provides fast convergence when the topology structure of the Spanning Tree changes and the load balancing is completed between redundant links using the "uplink link group. Enable the blocked port to skip the listening and learning statuses and directly switch to the forwarding status.

PostFast is used to skip the normal Spanning Tree operation on the access layer switch port to speed up the access of the terminal workstation to the network. Its function is to allow the switch port to skip the listening and learning status and directly switch from the blocking status to the forwarding status. This port can only be used to connect a single host or server. It cannot connect to network devices such as hubs, Concentrator, switches, and bridges.

The BPDU Filter causes the switch to stop sending BPDUs on the specified port. The BPDUs entering the port will not be processed, and the port status will be immediately converted to the forwarding status.

Switch STP configuration instance 1

Catalyst 3500:

1) enable or disable STP

Format: spanning-tree vlan <vlan id> (Enabled)

No spanning-tree vlan <vlan id> (disabled)

2) set the primary root

Format: spanning-tree vlan <vlan id> root primary

3) backup root

Format: spanning-tree vlan <vlan id> root secondary

4) configure the Spanning Tree priority

Format: spanning-tree vlan <vlan id> priority <0 ~ 61440>

5) configure the optional function of the BackboneFast spanning tree.

Format: spanning-tree BackboneFast

6) configure the optional UplinkFast Spanning Tree Function

Format: spanning-tree UplinkFast

Spanning-tree UplinkFast max-update-rate <0 ~ 32000>

The value of max-update-rate is 0 ~ 32000, in packet/s ).

7) configure the optional function of the PortFast Spanning Tree

Format: spanning-tree portfast default

8) configure the optional BPDU Filter Spanning Tree Function

Format: spanning-tree portfast bpdufilter default

Switch STP configuration instance 2

Catalyst 6500:

1) enable or disable STP

Format: set spantree enable <vlan id> (enable STP)

Set spantree disable <vlan id> (disable STP)

2) set the primary root

Format: set spantree root <vlan id>

3) backup root

Format: set spantree root secondary <vlan id>

4) configure the Spanning Tree priority

Format: set spantree priority Level

5) configure the optional function of the BackboneFast spanning tree.

Format: set spantree backbonefast enable

Set spantree backbonefast disable

6) configure the optional UplinkFast Spanning Tree Function

Format: set spantree uplinkfast enable

Set spantree uplinkfast enable rate <station_update_rate>

The default value of <station_update_rate> is 15 packet/100 ms.

7) configure the optional function of the PortFast Spanning Tree

Format: set spantree portfast module No./port number enable

Set spantree portfast module No./port number disable

Set spantree portfast module No./port number default portfast is enabled by default)

8) configure the optional BPDU Filter Spanning Tree Function

Format: set spantree portfast bpdu-filter enable all ports enable bpdu-filter)

Set spantree portfast bpdu-filter disable bpdu-filter)

Set spantree portfast bpdu-filter module number/port number enable bpdu-filter)

Set spantree portfast bpdu-filter module number/port number disable bpdu-filter)

Set spantree portfast bpdu-filter module number/port number default to default)

Two STP configuration instances are provided for you. You can refer to the above content to complete the STP configuration process of your switch.