Who has been stealing my packets

chris.king · ‎11-17-2006

Hi there!,

i'm a newbe to the Cisco forum site. Anyway here is my case. I have a 3750 client stack that is connected to a 3Com backbone (eek!) which also is connected to my 2950 server switch. So the client traffic goes from the 3750s to the 3Com to the 2950. OK, now for my problem:

I have about 300 input errors a day on the Cisco switches and a sporadically slow download times for my users.

Here is a small excert of my error.

Server Switch

2950-LL-1#show interface GigabitEthernet0/1

GigabitEthernet0/1 is up, line protocol is up (connected)

Hardware is Gigabit Ethernet, address is 0012.013c.e119 (bia 0012.013c.e119)

MTU 1500 bytes, BW 1000000 Kbit, DLY 1000 usec,

reliability 255/255, txload 3/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s

input flow-control is off, output flow-control is on

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:00, output 00:00:05, output hang never

Last clearing of "show interface" counters 02:10:50

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 1835000 bits/sec, 1223 packets/sec

5 minute output rate 15615000 bits/sec, 1663 packets/sec

10379334 packets input, 1442397616 bytes, 0 no buffer

Received 10804 broadcasts (0 multicast)

0 runts, 0 giants, 0 throttles

144 input errors, 144 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 4729 multicast, 0 pause input

0 input packets with dribble condition detected

14849607 packets output, 589344334 bytes, 0 underruns

0 output errors, 0 collisions, 0 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

Client Stack

3750-LL-1#show interface GigabitEthernet2/0/1

GigabitEthernet2/0/1 is up, line protocol is up (connected)

Hardware is Gigabit Ethernet, address is 0012.809d.9e81 (bia 0012.809d.9e81)

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX SFP

input flow-control is off, output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:04, output 00:00:32, output hang never

Last clearing of "show interface" counters 02:11:04

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 1966000 bits/sec, 492 packets/sec

5 minute output rate 1410000 bits/sec, 521 packets/sec

7792239 packets input, 3253250758 bytes, 0 no buffer

Received 16785 broadcasts (0 multicast)

0 runts, 0 giants, 0 throttles

13 input errors, 13 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 8637 multicast, 0 pause input

0 input packets with dribble condition detected

6325635 packets output, 1110474596 bytes, 0 underruns

0 output errors, 0 collisions, 0 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

None of the other ports on the switches have errors and the 3Com also "seems" to be fine.

The switches are coonected with 1000BaseSX

Please help as my users are starting to moan!

lgijssel · ‎11-17-2006

When the issue is related to your fiber links, it is necessary to know the type of fiber that is used in your network.

Is the cable 62.5/125 or 50/125?

What are the distances?

What type of connectors do you use on the patchpanel?

Have you applied a mode conditioning patchcord where required? Please check the link below to see if and where this might be the case:

http://www.cisco.com/en/US/products/hw/modules/ps5455/products_data_sheet09186a008014cb5e.html

Regards,

Leo

chris.king · ‎11-20-2006

Hi Leo,

thanks for your prompt answer.

My Fiber installation cable between the 3750 Stack and the 3Com is 50/125 and is 56M long.

The 3750 Stack is connected to the Fiber patch panel with a ST connector.

The 3Com switch is connected to the fiber patch panel with a MTRJ/ST connector.

All cables are multimode.

I hope that this helps.

BTW, I have a lot more input errors on the server switch 1000 Base SX port than on the client stack 1000 Base SX port.

regards,

Chris.

Michael Sales · ‎11-21-2006

Hi,

I'm going to assume the fiber for both Cisco switches go to the 3com? How is the 3com gig ports configured? Auto or static to Full 1000Mb? the 3750 is set to auto by the config posted and The 2950 is configured to 1000Mb Full duplex.

CRC errors and input errors on switches points to a config mismatch between the 3com and both cisco's.

In my case, I had these errors when I configure my Cisco 3x and 2x switches to nortel switches. In some cases the Gig ports on the Cisco's needed to be set to nonegotiate. or I static the speed to 1000 and keep the duplex to auto.

Most times.. Auto on both should fix this. but due to hardware differences, you may need to do some testing.

Hope this helps

chris.king · ‎11-24-2006

Thanks curryjustine!

I have set up everything to auto neg.

I have actually decided to do the following:

Replace the Cat. 2950 (Server switch) + 3Com (Core switch) with 1 Cat 3750/48 + SFP fx Modules.

Connect the 3750 client stack directly to the new 3750 and I intend on replacing all of my fiber optic cables that were connecting the 3750 stack to the 3Com to the 2950!

I'll let you all know if this solves my worries or not. Anyway I will have a better feeling if I kick out this 3Com thing!

cu,

Chris.