RSTP-MSTP
一、STP
1.STP的端口状态
a.侦听(listening)15s
b.学习(learning)15s
c.转发(forwarding)
d.阻塞(blocking)20s
2.STP选举
a.选举根桥:先比较优先级,再比较MAC地址,越小越好,默认32768
b.选举根端口,每个非根交换机只有一个根端口,通过比较cost值,按入口方向计算
c.选举指定端口,根桥的所有端口都是指定端口
总结:
a.每个冲突域只有一个指定端口
b.根桥的所有端口都是指定端口
c.比较到根桥的开销
d.如果cost值相同,则比较自己的优先级和MAC
二、.portfast(又叫边缘端口)
a.相对普通STP,节省30s
b.不要在接交换机的接口开启
c.不能在开启portfast的接口上开启trunk
d.一般用在接入层交换机
命令:
R1(config)#spanning-tree portfast
如果要在交换机上全部开启:
SW1(config)#spanning-tree portfast default
如果要在某个接口上禁用此功能:
SW1(config)#spanning-tree portfast disable
三、uplinkfast
1.block端口要过30s才能转为forwarding状态,为了能快速转为fordwarding状态,我们可以用uplinkfast技术
SW1(config)#spanning-tree uplinkfast
2.全局起效,一般用于接入层交换机
3.启用后与未启用相比有三点变化:增加了uplinkfast标识,将优先级强制改为49152,cost值增加3000
四、backbone fast
sw1和sw3之间的骨干线路down了,看sw2 9口何时可以恢复
1.建议所有交换机都启用
2.节约是BLK到LIS的20s老化时间
3.sw2启用backbone fast后,收到次级BPDU后,会通过RP发送一个RLQ(router link quest)命令,根桥收到后,回应response,sw2收到后,会将9口直接从BLK转为LIS状态;
五、RSTP(Rapid Spanning Tree Protocol,802.1w)
1.RSTP端口状态:
a.discarding(BLK&LIS):
b.learning:
c.forwarding:
2.RSTP端口角色:
3.RSTP的过程
根桥发送proposal,A收到后,将其他所有接口全部同步(BLK),回应agreement
4.建议在所有交换机上都配置
五、MSTP(Multiple STP,802.1S)
1.针对一个网络中有大量VLAN(上千个),这时如果还用PVST,每两秒根桥就要发送上千个BPDU,会造成收敛很慢,消耗大量资源,这时就可应用MSTP,MSTP就是将VLAN分组,每一组有不同的根桥和备份根桥
2.
3.配置:
a.开启mst:
SW1(config)#spanning-tree mode mst
SW1(config)#do sh spanning-tree
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address aabb.cc00.0100
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address aabb.cc00.0100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Et0/0 Desg BLK 2000000 128.1 Shr
Et0/1 Desg BLK 2000000 128.2 Shr
Et0/2 Desg BLK 2000000 128.3 Shr
Et0/3 Desg BLK 2000000 128.4 Shr
Et1/0 Desg BLK 2000000 128.5 Shr
Et1/1 Desg BLK 2000000 128.6 Shr
Et1/2 Desg BLK 2000000 128.7 Shr
Et1/3 Desg BLK 2000000 128.8 Shr
b.配置mst
SW1(config)#spanning-tree mst configuration SW1(config-mst)#instance 1 vlan 1-5 SW1(config-mst)#instance 2 vlan 6-10
SW1#show spanning-tree mst ##### MST0 vlans mapped: 11-4094 Bridge address aabb.cc00.0100 priority 32768 (32768 sysid 0) Root this switch for the CIST Operational hello time 2 , forward delay 15, max age 20, txholdcount 6 Configured hello time 2 , forward delay 15, max age 20, max hops 20 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 2000000 128.1 Shr Bound(STP) Et0/1 Desg FWD 2000000 128.2 Shr Et0/2 Desg FWD 2000000 128.3 Shr Et0/3 Desg FWD 2000000 128.4 Shr Et1/0 Desg FWD 2000000 128.5 Shr Et1/1 Desg FWD 2000000 128.6 Shr Et1/2 Desg FWD 2000000 128.7 Shr Et1/3 Desg FWD 2000000 128.8 Shr ##### MST1 vlans mapped: 1-5 Bridge address aabb.cc00.0100 priority 32769 (32768 sysid 1) Root this switch for MST1 Interface Role Sts Cost Prio.Nbr Type ---------------- ---- --- --------- -------- -------------------------------- Et0/0 Desg FWD 2000000 128.1 Shr Bound(STP) Et0/1 Desg FWD 2000000 128.2 Shr Et0/2 Desg FWD 2000000 128.3 Shr Et0/3 Desg FWD 2000000 128.4 Shr Et1/0 Desg FWD 2000000 128.5 Shr Et1/1 Desg FWD 2000000 128.6 Shr Et1/2 Desg FWD 2000000 128.7 Shr Et1/3 Desg FWD 2000000 128.8 Shr
c.为不同组配置不同的根桥
SW1(config)#spanning-tree mst 1 ? priority Set the bridge priority for the spanning tree root Configure switch as root
d.查看mst配置情况
SW1#sh spanning-tree mst configuration Name [] Revision 0 Instances configured 3 Instance Vlans mapped -------- --------------------------------------------------------------------- 0 11-4094 1 1-5 2 6-10 -------------------------------------------------------------------------------
六、EtherChannel
1.作用:
a.将多条物理链路逻辑绑定,形成一条逻辑链路
b.负载均衡
c.感官上是一个逻辑端口
d.冗余
2.DTNP(Dynamic Trunk Negotiation Protocol)
a.PAgP(Port Aggregation Protocol)思科私有
b.LACP(Link Aggregation Control Protocol):802.3ad
3.配置
a.PAgP:auto(只收不发)、desirable(也收也发)、一边auto一边desirable可以建立连接
b.LACP:active(两遍都是可以建立连接)、passive(两遍都是不可以建立连接)、一边active一边passive可以建立连接
c.on
4.配置etherchannel的条件
5.负载分担
a.基于源MAC地址做负载分担
SW1(config)#port-channel load-balance ? dst-ip Dst IP Addr dst-mac Dst Mac Addr src-dst-ip Src XOR Dst IP Addr src-dst-mac Src XOR Dst Mac Addr src-ip Src IP Addr src-mac Src Mac Addr
SW1#sh etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use f - failed to allocate aggregator M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port Number of channel-groups in use: 1 Number of aggregators: 1 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(SU) - Et0/0(P) Et0/1(P)
七、VTP安全
1.BPDU Guard
a.一般做在接入层交换机
b.一般下面接PC,禁止此接口接受BPDU
c.如果此接口收到BPDU,就变为err-disable状态(类似down)
d.可以手动恢复、也可自动恢复
SW1(config-if)#spanning-tree bpduguard enable
e.自动恢复命令:
SW1(config)#errdisable recovery cause bpduguard
SW1#sh errdisable recovery ErrDisable Reason Timer Status ----------------- -------------- arp-inspection Disabled bpduguard Enabled channel-misconfig (STP) Disabled dhcp-rate-limit Disabled dtp-flap Disabled gbic-invalid Disabled inline-power Disabled l2ptguard Disabled link-flap Disabled mac-limit Disabled link-monitor-failure Disabled loopback Disabled oam-remote-failure Disabled pagp-flap Disabled port-mode-failure Disabled pppoe-ia-rate-limit Disabled psecure-violation Disabled security-violation Disabled sfp-config-mismatch Disabled storm-control Disabled udld Disabled unicast-flood Disabled vmps Disabled psp Disabled dual-active-recovery Disabled Timer interval: 300 seconds Interfaces that will be enabled at the next timeout:
可以修改恢复时间:
SW1(config)#errdisable recovery interval 30
交换机所有接口都做BPDU防护:
SW1(config)#spanning-tree portfast bpduguard default
级联上行接口必须关闭bpduguard:
SW1(config-if)#spanning-tree bpduguard disable
2.BPDU filter
a.对收到的BPDU执行drop操作
SW1(config-if)#spanning-tree bpdufilter enable
其余命令类似guard
注意:guard不接受BPDU,但还发,而filter不接受也不发送
八、根桥防护(Root Guard)
1.对于外部接进来且拥有更优BPDU的交换机,与其相连的接口配置root guard,端口会显示不一致状态,然后将此端口置为broken状态,如果过一定时间后没有再收到更优BPDU,则会自动打开
SW1(config-if)#spanning-tree guard root
九、防环
B和C之间通过两根网线进行收发,整个图中运行STP,稳定状态下C向B的发送端口为BLK状态,当B向C的网线断掉后,C收不到B发来的BPDU,过20s后C向B的端口变会变为LIS状态,此时,B向C的端口为DP,C会向B也发送BPDU,但为次优BPDU,B还是认为自己端口为DP,C因为收不到B的BPDU,也认为自己的到B 的端口为BPDU,此时整个网络就全通了,就形成了环路,主要是光纤口出问题。
1.单向链路出现问题,直接将整个端口BLK
SW1(config)#udld enable
SW1(config-if)#udld port
2.
SW1(config-if)#spanning-tree guard loop
建议配置在根端口或交替端口上
3.udld和loop区别
a.loop能自动恢复,UDLD需要配置
b.loop建议配置在根端口或交替端口上,UDLD建议在所有链路上配置
c.loop是解决软件问题(端口拥塞、CPU忙),UDLD是解决硬件问题(网口坏了,线坏了)