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New Member

Duplex mismatch between Router and Core Switch, %CDP-4-DUPLEX_MISMATCH

Hi,

I have a problem here. There is 10M links for the site. It's having duplex mismatch between Router1 and CoreSW2. The connection are as below;

Router1 (G0/1) <=====Duplex mismatch"=====>(G0/11)CoreSW2<=====Fine=====>(G0/2.156)Router2

When we change the configuration on Int G0/11, CoreSW2 to Full-Duplex and Speed 100Mbps, the link went down. Then we configure it back as Half-Duplex and Speed 100Mbps.

Can anyone please advise on how to solve this issue? Is there any misconfiguration between the link or need to change some interface media?

Thanks in advance.

Router1:

======

Router1#sh int GigabitEthernet0/1

GigabitEthernet0/1 is up, line protocol is up

  Hardware is MV96340 Ethernet, address is 001e.f7e5.b741 (bia 001e.f7e5.b741)

  Description: *** 10M Tata to Chennai, in-che-colo-partrtr01 ID: New: 4008001438 / Old: 77-14110067 ***

  Internet address is 10.127.189.26/30

  MTU 2000 bytes, BW 100000 Kbit, 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 T

  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 1d14h

  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 83000 bits/sec, 30 packets/sec

  5 minute output rate 33000 bits/sec, 30 packets/sec

     23984796 packets input, 2835615576 bytes, 0 no buffer

     Received 17326 broadcasts, 0 runts, 0 giants, 0 throttles

     30 input errors, 0 CRC, 30 frame, 0 overrun, 0 ignored

     0 watchdog, 0 multicast, 0 pause input

     0 input packets with dribble condition detected

     19209986 packets output, 1977760822 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

Router1#

Jul 31 23:18:21.420 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/1 (not half duplex), with CoreSW2 GigabitEthernet0/11 (half duplex).

Jul 31 23:19:21.425 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/1 (not half duplex), with CoreSW2 GigabitEthernet0/11 (half duplex).

Jul 31 23:20:21.429 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/1 (not half duplex), with CoreSW2 GigabitEthernet0/11 (half duplex).

CoreSW2
=======

CoreSW2>sh int Gi0/11

GigabitEthernet0/11 is up, line protocol is up (connected)

  Hardware is Gigabit Ethernet, address is 001e.4913.608b (bia 001e.4913.608b)

  Description: *** Sasken ***

  MTU 9000 bytes, BW 100000 Kbit, DLY 100 usec,

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

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Half-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 00:00:28, 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 34000 bits/sec, 33 packets/sec

  5 minute output rate 88000 bits/sec, 34 packets/sec

     6033864740 packets input, 1448080850993 bytes, 0 no buffer

     Received 6045789 broadcasts (0 multicasts)

     0 runts, 0 giants, 0 throttles

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

     0 watchdog, 6045696 multicast, 91761294 pause input

     0 input packets with dribble condition detected

     7957047026 packets output, 7248383697947 bytes, 0 underruns

     0 output errors, 212968 collisions, 17 interface resets

     0 babbles, 2686383 late collision, 0 deferred

     0 lost carrier, 0 no carrier, 0 PAUSE output

     0 output buffer failures, 0 output buffers swapped out

Jul 31 23:15:02.650 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/11 (not full duplex), with iRouter1 GigabitEthernet0/1 (full duplex).

Jul 31 23:16:02.646 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/11 (not full duplex), with iRouter1 GigabitEthernet0/1 (full duplex).

Jul 31 23:17:02.650 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/11 (not full duplex), with Router1 GigabitEthernet0/1 (full duplex).

Jul 31 23:18:02.646 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/11 (not full duplex), with Router1 GigabitEthernet0/1 (full duplex).

Jul 31 23:19:02.650 UTC: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet0/11 (not full duplex), with Router1 GigabitEthernet0/1 (full duplex).

Router2

======

Router2>sh int Gi0/2.156

GigabitEthernet0/2.156 is up, line protocol is up

  Hardware is BCM1250 Internal MAC, address is 0021.563a.581a (bia 0021.563a.581a)

  Description: 10M EoSDH Tata Teleservices to Sasken Bangalore, in-blr-sasken-extrartr01 ID:New 4008001438 / Old  77-14110067 ***

  Internet address is 10.127.189.25/30

  MTU 2000 bytes, BW 1000000 Kbit, DLY 10 usec,

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

  Encapsulation 802.1Q Virtual LAN, Vlan ID  156.

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

  Last clearing of "show interface" counters never

Router21>

Router2>sh int Gi0/2   

GigabitEthernet0/2 is up, line protocol is up

  Hardware is BCM1250 Internal MAC, address is 0021.563a.581a (bia 0021.563a.581a)

  Description: cvcolo-coresw02 Gi0/5 ***

  MTU 2000 bytes, BW 1000000 Kbit, DLY 10 usec,

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

  Encapsulation 802.1Q Virtual LAN, Vlan ID  1., 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: 0/75/65/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: Class-based queueing

  Output queue: 0/1000/64/0 (size/max total/threshold/drops)

     Conversations  0/2/256 (active/max active/max total)

     Reserved Conversations 3/3 (allocated/max allocated)

     Available Bandwidth 250000 kilobits/sec

  5 minute input rate 84000 bits/sec, 91 packets/sec

  5 minute output rate 110000 bits/sec, 45 packets/sec

     10330613341 packets input, 1815547116247 bytes, 22 no buffer

     Received 261218305 broadcasts, 0 runts, 0 giants, 0 throttles

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

     0 watchdog, 178212613 multicast, 0 pause input

     0 input packets with dribble condition detected

     6112381585 packets output, 5097320965256 bytes, 0 underruns

     4 output errors, 0 collisions, 3 interface resets

     0 babbles, 0 late collision, 0 deferred

     4 lost carrier, 0 no carrier, 0 pause output

     0 output buffer failures, 0 output buffers swapped out

2 REPLIES
Cisco Employee

Re: Duplex mismatch between Router and Core Switch, %CDP-4-DUPLE

Hello,

The duplex mismatch happens when the two ports do not negotiate the

speed/duplex/other parameters. Please configure both ends to negotiate the

speed/duplex settings. If your link is 100 Mbps, then you can configure

traffic shaping to limit the bandwidth.

http://www.cisco.com/en/US/customer/products/hw/switches/ps700/products_tech

note09186a00800a7af0.shtml#autoneg_valid

http://www.dell.com/content/topics/global.aspx/power/en/ps1q01_hernan?c=us&c

s=555&l=en&s=biz

Hope this helps.

Regards,

NT

New Member

Re: Duplex mismatch between Router and Core Switch, %CDP-4-DUPLE

You should do the following, (btw I recommend setting speed to 1000 not 100 since they are both Gig ports unless you trying to limit your bandwidth)

anyways by the output on your log the problem is with CoreSW2 gi0/11 its only set to half duplex.

I recommend making the following changes

on Router1 (G0/1)

speed 1000

duplex full

and on CoreSW2 (G0/11)

speed 1000

duplex full

that should fix your duplexing problem.

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