 2-3 packets per second): Chapter 8: Spanning Tree 3550-IOS#sho int f0/15 FastEtherneto/15 is up, line protocol is up (connected) Hardware is Fast Ethernet, address is 000f.8f5c.5a0f (bia 000f.8f5c.5a0f) MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, media type is 10/100BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:10, output 00:00:00, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 1000 bits/sec, 2 packets/sec 5 minute output rate 1000 bits/sec, 3 packets/sec 5778444 packets input, 427859448 bytes, 0 no buffer Received 5707586 broadcasts (o multicast) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 5707585 multicast, 0 pause input 0 input packets with dribble condition detected 2597516 packets output, 213866427 bytes, 0 underruns A useful tool when you're troubleshooting a broadcast storm is the show processes cpu history command. This command displays an ASCII histogram of the CPU utilization over the past 72 hours. It produces three graphs: CPU percent per second (last 60 seconds) CPU percent per minute (last 60 minutes) CPU percent per hour (last 72 hours) Here is the output from the show process cpu history command on switch B, which shows 0-3 percent CPU utilization over the course of the last minute (the remaining graphs have been removed for brevity): 3550-IOS#sho proc cpu history 11111 33333 11111 CPU% per second (last 60 seconds) Broadcast Storms The numbers on the left side of the graph are the CPU utilization percentages. The numbers on the bottom are seconds in the past (0 = the time of command execution). The numbers on the top of the graph show the integer values of CPU utilization for tha