2651XM路由器问题

CCNA9116

我在一台2651XM上的F0/0接口配置IP地址后，执行no shut命令后。路由器会不定时的出现下面的错误
*Sep  5 10:52:56.374: %AMDP2_FE-3-UNDERFLO: FastEthernet0/0 transmit error
*Sep  5 10:52:56.374: %AMDP2_FE-3-UNDERFLO: FastEthernet0/0 transmit error
*Sep  5 10:53:06.374: %AMDP2_FE-3-UNDERFLO: FastEthernet0/0 transmit error
*Sep  5 10:53:06.374: %AMDP2_FE-3-UNDERFLO: FastEthernet0/0 transmit error
我把配置文件清空后重新配置，还是如此。而且将该接口的网线拔出后还是会出现这个错误。
望高手们帮忙分析下，什么原因导致这个错误，怎么解决，谢谢了。

王晓强

一般是考虑双工速率问题。
接口下配置全双工。
对端是什么设备呢？

王晓强

贴一个之前类似的案例：
查询cisco doc 终于发现问题：双方双工不匹配。
Late collisions are almost always the result of duplex mismatch.The station that reports the late collision merely indicates the problem; it is generally not the cause of the problem. Possible causes are usually incorrect cabling or a non-compliant number of hubs in the network. Bad network interface cards (NICs) can also cause late collisions.
解决办法：将收发器调为10M half-duplex

Comment:
1、这种问题只会出现在 half-duplex Ethernet.中，不会出现在full-duplex Ethernet, 因为collision detection is disabled in full-duplex。如果WIC-1ENET工作在half-duplex,而对端10/100M自动协商又不能正确工作，选择10M half-duplex，就会出现这种问题。

2、关于冲突的几个计数器
xxx#sh interfaces e1/0
Ethernet1/0 is up, line protocol is up
Hardware is AmdP2, address is 0002.16f5.66a8 (bia 0002.16f5.66a8)
Internet address is 218.104.xxx.xxx/30
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 01:10:38
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 3000 bits/sec, 5 packets/sec
5 minute output rate 27000 bits/sec, 6 packets/sec
     44048 packets input, 30038741 bytes, 0 no buffer
     Received 41 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 input packets with dribble condition detected
     43157 packets output, 5700826 bytes, 0 underruns
     0 output errors, 127 collisions, 0 interface resets
     0 babbles, 0 late collision, 59 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out


Late Collisions Counter
When a collision is detected by a station after it has sent the 512th bit of its frame, it is counted as a late collision.

The Deferred Counter
The deferred counter counts the number of times the interface has tried to send a frame, but found the carrier busy at the first attempt (Carrier Sense). This does not constitute a problem, and is part of normal Ethernet operation(已经启动2进制退避算法).

roy

强哥的回复真是强大啊，不愧是强哥

明天¤晴天℃

强哥的回答 V5

思博网络

   强哥一回答，其他人都不敢插嘴了！

亮晶晶

回答的真强大。

CCNA9116

回复 2 # andersen 的帖子

对端同样是2651XM路由器，很奇怪的是，我在对端接口设置了速率100双工为full，在这台路由与之相连的接口也设为速率100双工为full，同样会出这个错误。出错后再把接口的双工模式改为Auto，又正常了。我怀疑这个是不是接口硬件的问题。