right ok so is this

Ozzy Schoonover · ‎08-18-2015

Hi fellow Cisco-ers,

Today I was working with a Cisco 3845 and came across an interesting issue that I wanted to run past the educated community for input.

I couldn't get the router to pass traffic on gi 0/0, but gi 0/1 works fine. There was no sfp and the media was set to rj45 on the interface. After further playing with the device I noticed that gi 0/0 passes traffic when set to 10 or 100 Mbps using the speed command. Can anyone confirm that this is a sign of a dead/dying interface or tell me what additional things I can look at? I'd love to use the port at gigabit speeds, but will get sfp's and go that way if the port is unfixable.

Thanks in advance for your expertise,

-Ozzy

Mark Malone · ‎08-19-2015

Can you share the sh run int g0/0 and the show int g0/0 please

You should be able to use 3845 as 1000 on copper I have it working on my remote routers which are all 3845s

Ozzy Schoonover · ‎08-19-2015

Hi Mark,

Here are the requested outputs.

interface GigabitEthernet0/0
 ip address dhcp
 duplex auto
 speed auto
 media-type rj45

GigabitEthernet0/0 is up, line protocol is up 
  Hardware is BCM1125 Internal MAC, address is 001b.d4dd.5a60 (bia 001b.d4dd.5a60)
  Internet address will be negotiated using DHCP
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is RJ45
  output flow-control is XON, input flow-control is XON
  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 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 15000 bits/sec, 27 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     6911 packets input, 414660 bytes, 0 no buffer
     Received 6911 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     23 packets output, 5579 bytes, 0 underruns
     20 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     20 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

Here is a show int after using speed 100 and rebooting the modem:

GigabitEthernet0/0 is up, line protocol is up 
  Hardware is BCM1125 Internal MAC, address is 001b.d4dd.5a60 (bia 001b.d4dd.5a60)
  Internet address is 184.166.211.xx/21
  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 RJ45
  output flow-control is XON, input flow-control is XON
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:08, 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 24000 bits/sec, 51 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     22753 packets input, 1367326 bytes, 0 no buffer
     Received 22751 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     85 packets output, 17718 bytes, 0 underruns
     28 output errors, 0 collisions, 3 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     28 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out

I have even done a DHCP debug and it shows things as being sent, but no replies or ack from anything on the other side when at gigabit speeds. To me this definitely seems like a bad interface, but I'm only at a CCNA right now =) What does your brain say?

Bodrul islam · ‎08-19-2015

Have you tried updating to latest firmware?

Ozzy Schoonover · ‎08-19-2015

I haven't. When I bought the router, it came with two 12.x ios images on the cf card. I have switched between them but haven't been able to try the latest ios for the router. I'm a student and don't have an active support contract with Cisco which prevents me from getting the latest image.

Bodrul islam · ‎08-19-2015

right ok so is this interface on the router connected to 100Mbs or gigabit port on edge device?

Ozzy Schoonover · ‎08-19-2015

Connected to edge device via gigabit port, but will only pass data if set to 100Mbps.

Mark Malone · ‎08-19-2015

Does the device your auto-negotiating speeds with support 1000Mb

you get an ip address when you hardcode to 100Mb , have you tried to hardcode it to 1000mb with full duplex instead of auto

This is a public ip your pulling in so im guessing your connecting to some kind of ISP modem is that correct?

If that's the case you could confirm with whoever supplied that what exactly its capable of supporting

A quick test give the interface a static ip connect a laptop to it then with a gig nic give it an ip address same range and see if you can ping between them at 1000/full see what the results

I would be wary to think the interface is hardware faulty as it works fine on 100mb it could be ios related but I would test that first to rule it out , remove the dhcp and just test that way

Ozzy Schoonover · ‎08-19-2015

I can confirm that the ISP modem supports 1000Mb by connecting to my laptop. And I did try coding it to a gig full duplex with same symptoms.

I have also tried using that port as a LAN port with a static address connected directly to my laptop (gig interface) and pings fail. They do go between time outs and destination unreachable.

Is there a good, legitimate way of me getting the latest IOS from Cisco to try that path?

Mark Malone · ‎08-19-2015

Without a contract there's no real legitimate way but like everything else most things that have been around a while its already up on the internet I just copied my current 3845 ios into google and a site came up full of all the releases, I don't condone it but there up there if you have no other option and are willing to use them

remember if your upgrading to test further check your ram most of the version 15s need 512 and most routers that come with version 12 only have 256 so I would only upgrade to something in same specs

your could try a debug ip packet detail to see if it shows anything further but the fact it wont work with a laptop directly connected as well something's definitely not right

Ozzy Schoonover · ‎08-19-2015

I might try a debug ip packet detail, but that one is scary because it seems to get received traffic alright. Is there any way to debug ip packet only on outgoing packets?

Also, I just upgraded to 1 GB ram so it should be okay =) I'll chat with the Cisco rep at work and see if he can get me an image through the right channels.

Thanks for all of your time on this. I will investigate further when I get home. I will bring some SFP's and a switch home to test gi 0/0's sfp port and see if I have the same issue there.

Ozzy Schoonover · ‎08-20-2015

~~I did a debug ip packet detail and it didn't provide any useful information in this case~~. I even convinced our Cisco guy to get me an updated IOS image and I feel comfortable saying that it is bad hardware. Same issue when using Gigabit Fiber SFP. Thanks for the collaboration guys! If you think of anything else I can try please let me know =)

***EDIT***

Now that I re-read the output of debug ip packet:

IP: s=0.0.0.0 (GigabitEthernet0/0), d=255.255.255.255, len 317, input feature
UDP src=68, dst=67, MCI Check(80), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

mtu 0 ??

That doesn't seem right...

3845 interface only passes traffic in 10/100