Default STP Configuration
 
自定义STP 配置
 
Feature                                                                Default  Value
功能                                                                    缺省值
 
Enable state                                                         STP enable for all VLANs                                    
开启状态                                                            所有VLAN默认开启STP
                                        
Bridge priority                                                     32768
网桥优先级
                                       
STP port priority (configurable on                      128
a per-port basis--used on LAN ports
configured as Layer2 access ports)
基于2层访问端口的每端口优先级
 
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
基于2层访问端口的每端口成本
 
STP VLAN port priority(configurble on            128
a per-VLAN basis--used on LAN ports
configured as Layer2 trunk ports)
基于2层trunk端口的每VLAN优先级
 
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
基于2层trunk端口的每VLAN优先级
 
Hello  time                                                               2 seconds
hello 时间                                                                2 秒
 
Forward delay time                                                  15 seconds
转发延时                                                                  15 秒
 
Maximum aging time                                                20 seconds
最大生存时间                                                         20 秒
 
Mode                                                                        PVST
模式                                                                         每VLAN 生成树
 
Enabling   STP  
开启 STP
 
STP is enabled by default on VLAN 1 and on all newly created VLANs.
STP 在VLAN1和所有被创建的VLAN 上自动开启。
 
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).
可以基于VLAN 开启STP。基于每个VLAN实例维护STP。（除非你在VLAN上关闭STP）
 
To eanble STP on a per-VLAN basis, perform this task:
下面的命令开启基于每VLAN 的STP。
 
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
在1到4096上开启除保留VLAN以外的每VLAN STP。
 
Router(config)#default spanning-tree vlan vlan_id
Reverts all STP parameters to default values for the specified VLAN.
在选择的VLAN上恢复所有STP自定义值
 
Router(config)#no spanning-tree vlan vlan_id
Disable STP on the specified VLAN; see the following Cautions for information regarding this command.
关闭指定VLAN上的STP。注意查看命令后显示的警告信息。
 
Router(config)#end
exits configuration mode
退出配置模式
 
Router# show spanning-tree vlan vlan_id
Verifies that STP is enabled.
验证STP开启
 
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。