storm-control broadcast level 20.00
switch#sh storm
Interface Filter State Level Current
--------- ------------- ------- -------
Fa1/0/1 Forwarding 20.00% 0.00%
3、针对缺省STP配置无法排除的网络环路问题,利用STP的BPDUguard特性来预防广播风暴。此种环路情况示意图如下:
spanning-tree bpduguard enable
***值得注意的是bpduguard可以在全局下配置,也可以在每端口的基础上配置。如果在全局下配置,则只对配置了portfast的端口起作用,如果在端口下配置,则不用配置portfast
CPU utilization for five seconds: 19%/0%; one minute: 19%; five minutes: 19%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
15 20170516 76615501 263 0.31% 0.13% 0.12% 0 ARP Input
26 7383266801839439482 401 5.03% 4.70% 5.08% 0 Cat4k Mgmt HiPri
27 8870781921122570949 790 5.67% 7.50% 6.81% 0 Cat4k Mgmt LoPri
43 730060152 341404109 2138 6.15% 5.29% 5.28% 0 Spanning Tree
50 59141788 401057972 147 0.47% 0.37% 0.39% 0 IP Input
56 2832760 3795155 746 0.07% 0.03% 0.01% 0 Adj Manager
58 4525900 28130423 160 0.31% 0.25% 0.18% 0 CEF process
96 20789148 344043382 60 0.23% 0.09% 0.08% 0 Standby (HSRP)
如果交换机的CPU利用率较高,且大部分的资源都被“IP Input”进程占用,则基本可以确定网络中有大流量的数据
FastEthernet1/0/1 is up, line protocol is up (connected)
Queueing strategy: fifo
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 2000 bits/sec, 3 packets/sec
Received 241676 broadcasts (0 multicast)
如果找到一个端口的input rate非常高,且接收到的广播包也非常多,则基本可以找到来源,如果该端口下联的也是可管理的交换机,则再次执行此过程,直到找到一个连接PC或者HUB的端口
shutdown
4、查找产生异常流量的根源
全局模式下输入 : ip cef