cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements
Popup Hotspot Using ISR 1000 with WiFi/LTE for Teleworkers and Micro Branchesr
111
Views
0
Helpful
11
Replies
Highlighted
Participant

3560G failes to communicate with one device

Hello,

 

I have a strange problem that started at 3am last night.  I have a device that is connected to a 3560G, and it suddenly stopped communicating with the switch.  If I try and move it to any other port it will not work.  If I reset this device to factory default, and re configure it, with a different ip address, etc, it will still not communicate with the switch.

 

If I move this device to another switch, router or laptop, it has no problems communicating with them.  With that I have determined that the 3560G is at fault.

 

I am not able to reload the switch at this time, so I am wondering if there is something I need to try and clear from the switch.  At this point I can see the mac address table for the device on the correct port, but I cannot ping it.

 

Is there anything I can do to troubleshoot this other than clearing the arp and the mac address table for that port?

 

Thanks,

Dan.

Everyone's tags (1)
11 REPLIES 11
Highlighted
Hall of Fame Community Legend

I have a strange problem that

I have a strange problem that started at 3am last night.  I have a device that is connected to a 3560G, and it suddenly stopped communicating with the switch.  If I try and move it to any other port it will not work.  If I reset this device to factory default, and re configure it, with a different ip address, etc, it will still not communicate with the switch.
 

If I move this device to another switch, router or laptop, it has no problems communicating with them.  With that I have determined that the 3560G is at fault.

Question:  Is this device running on 1 Gbps line speed on the 3560CG and when you moved it to another switch, router or laptop did it negotiate to just 100 Mbps?

Highlighted
Beginner

Dan,If you connect a notebook

Dan,

If you connect a notebook to this switch port is it communicating with different speeds? ( speed, duplex, auto)?

Remote possibility, do you feel there is duplicate IP conflicting with this device. Is the interface clean - error, CRC reliability etc

I faced similar problem in the past resolved after the physical cabling was replaced by new CAT 6E..

Not sure if you have cable check or similar command on the switch.

Hope this helps..

Thanks,

 

 

 

 

 

Highlighted
Participant

Yes, if I connect a notebook

Yes, if I connect a notebook the port works fine.  No chance of a duplicate IP, as I had this device and nothing else connected.

 

 

There are no errors on the port either:

 

GigabitEthernet0/46 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0023.051f.e12e (bia 0023.051f.e12e)
  MTU 1500 bytes, BW 100000 Kbit/sec, 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 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:16, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 32807
  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
     1092041447 packets input, 2115068914 bytes, 0 no buffer
     Received 14832670 broadcasts (7179158 multicasts)
     5 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 7179158 multicast, 0 pause input
     0 input packets with dribble condition detected
     1303344359 packets output, 3606277833 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     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

 

Cable tests good too:

 

 

TDR test last run on: May 14 09:27:06

Interface Speed Local pair Pair length        Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi0/46    100M

                Pair A     94   +/- 4  meters Pair B      Normal
                Pair B     87   +/- 4  meters Pair A      Normal
                Pair C     1    +/- 4  meters Pair C      Open
                Pair D     1    +/- 4  meters Pair D      Open

 

 

Highlighted
Hall of Fame Community Legend

Cable tests good too

Cable tests good too

No it's not.  This is why I asked the initial question.  

 

Pair D     1    +/- 4  meters Pair D      Open

The behaviour with your device is NORMAL.  Why?  Look at the result of Pair "D".  Pair "D" controls GigabitEthernet and the test results shows OPEN circuit and an open circuit means BAD.  This is why if you plug this to a Cisco GigabitEthernet switch port the link goes down.  But if you plug this to FastEthernet switch port the link goes up.  

 

The cable distance shows the cable directly connected to the switch port is faulty and needs to be replaced.  Another thing, the distance is close to maximum limit of FastEthernet/GigabitEthernet of 100 metres.  

 

If you are unable to replace the cable and you need to connect this to the 3560CG then the only way force this link to go up is to set the speed of the port down to 100 Mbps using the interface command "speed auto 10 100".

 

Read more about TDR HERE.

 

Hope this helps.

Highlighted
Participant

I guess I failed to specify

I guess I failed to specify that this is connected to a 100Mbit device.  Not a Gigabit device.  So yes the cable tests good.

 

And I get a link at 100Mbps, getting the link is not the problem.  It won't communicate with the device over the link.  Things like CDP and mac address table work, but there is no tcp communication.

I had tried the speed 100, duplex full commands, didn't make a difference.  But again, I had a link all along.

Dan.

Highlighted
Hall of Fame Community Legend

Ok, take this device off the

Ok, take this device off the network and replace it with something.  See if you can see the same behaviour.  I am suspicious about your device.  Looking at the "sh interface" output, I can see regular input/output.  If there was something wrong with the link, you won't see any traffic or you'll only see one-way traffic (from the switch down to the device).  

 

Also, can you confirm this link is almost 100 metres long?

Highlighted
Beginner

Dan,Looks like  points are

Dan,

Looks like  points are coming inline now.

 

As you said notebook connected to this port works fine, this back's up the point that switch port may be  good.

Cable is almost reaching 100 meters max allowed distance in theory.

 Pair of cables C,D is showing open. Not sure why one pair length is 94 meter and other pair is 87.

One thing you can try is, if you have access to switch closet, try directly connecting this device to switch with a good quality new patch chord. This will eliminate all other variables on the table.

HTH..

Thanks,

subodh

 

 

 

Highlighted
Participant

Yes the cable is around 100

Yes the cable is around 100 meters.  The notebook works fine when connecting to the port and when connecting to the device with the same patch cord.  A new patch cord didn't make any difference either.

I am going to start replacing stuff today.  See how that goes.....eventually it will work once everything is replaced....

 

Dan.

 

 

Highlighted
Participant

Landed up replacing the

Landed up replacing the device, not the cable or patch cable, and all is well now.

 

Dan.

Highlighted
Participant

I can set it to 100Mbps and

I can set it to 100Mbps and it still does not work.  Does not make a difference which switch port either.

 

Dan.

Highlighted
Enthusiast

Is it possible to use

Is it possible to use Wireshark on this device and see what it is seeing from the switch? Or alternatively can you monitor session and see what is being sent and received on that port?

CreatePlease to create content
Content for Community-Ad