CCNA-25、RSTP

RSTP (802.1W)

根端口:非根网桥去选举
1、COST  100M 19  10M 100
2、send B-ID
3、SEND PORT-ID(端口的优先级+接口ID)
   spanning-tree vlan 1 port-priority 128
选举指定接口
根桥上的接口都是指定接口（基于链路)
比较该接口到达根桥的COST
比较B-ID

Rapid Spanning Tree Protocol(862.1w)

RSTP

802.1W相对于先前的802.1D生成树来说,在网络拓扑发生变化的时候提供更快的收敛速度，
RSTP中还集成了类似于uplink和backbonefast属性.

RSTP它把Broking接口变为（替代接口和备份接口）
RSTP Port States
RSTP 端口状态

在STP种与设备连接的接口是Port Fast，在RSTP中也有一类类似的Edge Ports接口

配置命令spanning-tree portfast

Functions similarly to PortFast（思科).
Configured by issuing the spanning-tree portfast command（思科)
When a edge port receives a BPDu,it generates a TCN.

switchport mode access模式下
*Full-duplex---point-to-point
*Half-duplex---shared
*通过接口命令修改其默认的链路类型spanning-tree link-type ?

Switch(config-if)#spanning-tree link-type ?
  point-to-point  Consider the interface as point-to-point
  shared          Consider the interface as shared

Switch(config-if)#spanning-tree link-type 

PVRST Implementation Commands

-Configuring
spanning-tree mode rapid-pvst    #全局模式下
-Verifying    #查验
show spanning-tree vlan 10
-Debugging
debug spanning-tree

Switch#show spanning-tree vlan 10

VLAN0010
  Spanning tree enabled protocol rstp
  Root ID    Priority    32778
             Address     5064.1700.ba00
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32778  (priority 32768 sys-id-ext 10)
             Address     5064.1700.ba00
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1               Desg BLK 4         128.2    P2p 

Switch#

STP  ----所有VAN 1棵生成树，.理论知识，不存在
RSTP ----所有TLAN1棵生成树+快速收敛
PVST ----每个LAN1棵生成树
rapid-pvst---每个江A的1棵生成树+快速收敛


MSTP结合了STP+PVST+RSTP的优点
多个VLAN 1棵生成树
100个VLAN
1-50实例1      每个实例就是一个生成树
51-100实例2
快速收敛
CCNP

MSTP一定要 instance 0 要设置成根桥