如何检查思科交换机（2960）是否丢失数据包（例如由于拥塞）？
用于解决此类问题的工具/命令是什么？
答案1
show int和命令都show int summary应该为您提供足够的信息，至少可以让您了解某个特定端口是否遇到了问题。
该show int summary命令将为您提供每个接口的输入/输出保持队列的概览以及当前每秒的位数和数据包数以及从输入/输出队列中删除的数据包数。
#show int summary
*: interface is up
IHQ: pkts in input hold queue IQD: pkts dropped from input queue
OHQ: pkts in output hold queue OQD: pkts dropped from output queue
RXBS: rx rate (bits/sec) RXPS: rx rate (pkts/sec)
TXBS: tx rate (bits/sec) TXPS: tx rate (pkts/sec)
TRTL: throttle count
Interface IHQ IQD OHQ OQD RXBS RXPS TXBS TXPS TRTL
-----------------------------------------------------------------------------------------------------------------
Vlan1 0 0 0 0 0 0 0 0 0
* Vlan2 1 0 0 0 6000 8 6000 4 0
FastEthernet0 0 0 0 0 0 0 0 0 0
GigabitEthernet1/0/1 0 0 0 0 0 0 0 0 0
GigabitEthernet1/0/2 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/3 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/4 0 0 0 0 9000 4 190000 19 0
* GigabitEthernet1/0/5 0 0 0 0 3000 2 36000 15 0
* GigabitEthernet1/0/6 0 0 0 0 3000 2 17000 13 0
GigabitEthernet1/0/7 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/8 0 0 0 0 114000 7 196000 30 0
* GigabitEthernet1/0/9 0 0 0 0 136000 32 270000 43 0
* GigabitEthernet1/0/10 0 0 0 0 7000 8 254000 27 0
GigabitEthernet1/0/11 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/12 0 0 0 0 0 0 12000 11 0
* GigabitEthernet1/0/13 0 0 0 15 1000 0 16000 13 0
* GigabitEthernet1/0/14 0 0 0 0 1000 1 13000 12 0
* GigabitEthernet1/0/15 0 0 0 0 1000 1 14000 12 0
GigabitEthernet1/0/16 0 0 0 0 0 0 36000 6 0
* GigabitEthernet1/0/17 0 0 0 0 8000 10 35000 43 0
GigabitEthernet1/0/18 0 0 0 0 0 0 0 0 0
GigabitEthernet1/0/19 0 0 0 0 0 0 0 0 0
GigabitEthernet1/0/20 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/21 0 0 0 0 23000 32 20000 22 0
* GigabitEthernet1/0/22 0 0 0 0 0 0 12000 11 0
* GigabitEthernet1/0/23 0 0 0 0 0 0 12000 11 0
GigabitEthernet1/0/24 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/25 0 0 0 0 0 0 78000 11 0
* GigabitEthernet1/0/26 0 0 0 0 0 0 12000 11 0
* GigabitEthernet1/0/27 0 0 0 0 7000 4 215000 20 0
* GigabitEthernet1/0/28 0 0 0 0 0 0 12000 11 0
GigabitEthernet1/0/29 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/30 0 0 0 0 1000 1 13000 13 0
GigabitEthernet1/0/31 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/32 0 0 0 0 0 0 12000 13 0
* GigabitEthernet1/0/33 0 0 0 0 0 0 12000 11 0
* GigabitEthernet1/0/34 0 0 0 0 51000 30 434000 56 0
* GigabitEthernet1/0/35 0 0 0 0 0 0 61000 14 0
* GigabitEthernet1/0/36 0 0 0 0 0 0 12000 11 0
* GigabitEthernet1/0/37 0 0 0 0 0 0 172000 42 0
* GigabitEthernet1/0/38 0 0 0 0 0 0 12000 12 0
* GigabitEthernet1/0/39 0 0 0 0 0 0 12000 12 0
* GigabitEthernet1/0/40 0 0 0 0 491000 832 63201000 5869 0
* GigabitEthernet1/0/41 0 0 0 0 1000 1 13000 13 0
* GigabitEthernet1/0/42 0 0 0 0 28000 3 62000 17 0
* GigabitEthernet1/0/43 0 0 0 0 0 0 112000 12 0
GigabitEthernet1/0/44 0 0 0 0 0 0 0 0 0
* GigabitEthernet1/0/45 0 0 0 0 0 0 14000 15 0
GigabitEthernet1/0/46 0 0 0 0 0 0 0 0 0
--More--
答案2
我将以下面的示例开始show interfaces。您应该能够看到哪些接口（如果有）显示数据包错误，此时您需要进行一些故障排除或诊断来确定原因。
[some-switch-thing]#sh int
FastEthernet0/0 is up, line protocol is up
Hardware is Gt96k FE, address is [some-MAC-address-thing] (bia some-MAC-address-thing)
Internet address is [some-IP-address-thing]
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, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:01, 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 112000 bits/sec, 51 packets/sec
5 minute output rate 207000 bits/sec, 46 packets/sec
329320347 packets input, 534153518 bytes
Received 4483582 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
320121443 packets output, 1884667704 bytes, 0 underruns
0 output errors, 0 collisions, 3 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out