12-18-2013 06:55 AM - edited 03-07-2019 05:08 PM
After connection Android device with JP1081 USB Ethernet adapter to Cisco 2960, the port to which the device is turned off. Android device with JP1081 operates in 10Mb/half-duplex.
What is the cause of failures and how to solve this problem?
The log shows the following entries:
ruekasw13#sh run int Fa0/20
Building configuration...
Current configuration : 51 bytes
!
interface FastEthernet0/20
description -tv
end
Dec 18 05:49:25: %LINK-3-UPDOWN: Interface FastEthernet0/20, changed state to up
Dec 18 05:49:26: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/20, changed state to up
ruekasw13#
Dec 18 05:49:58: %ETHCNTR-3-HALF_DUX_COLLISION_EXCEED_THRESHOLD: Collisions at FastEthernet0/20 exceed threshold. Considered as loop-back.
ruekasw13#
Dec 18 05:49:58: %PM-4-ERR_DISABLE: loopback error detected on Fa0/20, putting Fa0/20 in err-disable state
Dec 18 05:49:59: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/20, changed state to down
ruekasw13#
Dec 18 05:50:00: %LINK-3-UPDOWN: Interface FastEthernet0/20, changed state to down
ruekasw13#sh int Fa0/20
FastEthernet0/20 is down, line protocol is down (err-disabled)
Hardware is Fast Ethernet, address is 203a.0765.1314 (bia 203a.0765.1314)
Description: -tv
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Auto-duplex, Auto-speed, 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 never, output 00:03:09, 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 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
4377 packets input, 795370 bytes, 0 no buffer
Received 487 broadcasts (51 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 51 multicast, 0 pause input
0 input packets with dribble condition detected
82202 packets output, 10111549 bytes, 0 underruns
0 output errors, 162 collisions, 3 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out
12-18-2013 11:12 AM
Hi Granov,
collisions are a just normal part of the half-duplex CSMA/CD procedure, and are not considered errors at all. They are just retried. They are not considered errors until a packet suffers 16 of them in a row, and has to be discarded - known as "excessive collisions".
1. Disable the keepalive with these commands:
Switch#config t
Switch(config)# int f0/20
Switch(config-if)# no keepalive
2. If you don't want to turn off loopback detection/shutdown, you should
definitely enable loopback recovery (off by default, requiring manual
reset, an *awful* default!):
errdisable recovery cause loopback
errdisable recovery interval 60
3. run no shut on the interface fa0/20
Regards
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