Default STP Configuration

 

 

 

Enable state                                                         STP enable for all VLANs                                    

                                        

Bridge priority                                                     32768

                                       

STP port priority (configurable on                      128

a per-port basis--used on LAN ports

configured as Layer2 access ports)

 

STP prot cost (configurable on a per-                 Gigabit Ethernet :4

port basis--used on LAN ports                           Fast Ethernet :19

configured as Layer 2 access ports)                     Ethernet : 100

 

STP VLAN port priority(configurble on            128

a per-VLAN basis--used on LAN ports

configured as Layer2 trunk ports)

 

STP VLAN port cost (configurable on a              Gigabit Ethernet :4

per-VLAN basis--used on LAN ports                  Fast Ethernet :19

configured as Layer 2 trunk ports)                        Ethernet :100

 

Hello  time                                                               2 seconds

 

Forward delay time                                                  15 seconds

 

Maximum aging time                                                20 seconds

 

Mode                                                                        PVST

 

Enabling   STP  

 

STP is enabled by default on VLAN 1 and on all newly created VLANs.

 

You can eanble STP on a per-VLAN basis.The switch maintains a separate instance of  STP for

each VLAN (except on VLANs on  which you disable STP).

 

To eanble STP on a per-VLAN basis, perform this task:

 

Router (config)#spanning-tree vlan vlan_id

Enable STP on a per-vlan basis. The vlan_id value can be 1 through 4096,except reserved VLANs

 

Router(config)#default spanning-tree vlan vlan_id

Reverts all STP parameters to default values for the specified VLAN.

 

Router(config)#no spanning-tree vlan vlan_id

Disable STP on the specified VLAN; see the following Cautions for information regarding this command.

 

Router(config)#end

exits configuration mode

 

Router# show spanning-tree vlan vlan_id

Verifies that STP is enabled.

 

IEEE 802.1w    RSTP

 

替换端口  备份端口

 

丢弃状态 学习状态 转发状态

 

快速版本的PVST+    RPVST+  是RSTP实现的按VLAN版本

 

RSTP 只对 BPDU 的格式做了少量的变更。

对BPDU 中的端口状态和角色进行编码

处理提议和协定机制

RSTP BPDU 的类型是2，版本是2

 

7  拓朴变更

6 提议

54      00 未知  01 替代/备份  10 根 11 指定

3 学习

2 转发

1 协定

0 变更ACK

 

边缘端口   链路类型

 

交换机能够从端口的双工模式中获得链路类型，全双工模式的端口就是点到点的链路。