Setting up port duplex

[jahanzeb.feroze]

I am trying to set up the speed duplex as "full", but the port not allowing me this operation, showing the error of unrecognized command, however beside this port, all the other ports on same switch are accepting the command.

Note: Cross cable is connected to this port.

Please suggest

[Charles Hill]

4500 side set duplex auto?  If not set both sides auto.

[jahanzeb.feroze]

Want to set it to 1000 due to certain requirements, auto will not work for me.

Please help
 

[Charles Hill]

Can you copy and paste the output from

show run int g0/24

for both sides of the link that is experiencing half duplex?

[jahanzeb.feroze]

GigabitEthernet0/24 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0021.565b.9798 (bia 0021.565b.9798)
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Half-duplex, 100Mb/s, link type is auto, 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 00:00:00, output 00:00:14, 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 2000 bits/sec, 5 packets/sec
  5 minute output rate 1000 bits/sec, 3 packets/sec
     8532345 packets input, 685285873 bytes, 0 no buffer
     Received 6122657 broadcasts (0 multicasts)
     0 runts, 0 giants, 0 throttles
     244 input errors, 113 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 5923756 multicast, 0 pause input
     0 input packets with dribble condition detected
     1215095 packets output, 147874876 bytes, 0 underruns
     0 output errors, 65 collisions, 1 interface resets
     0 babbles, 23 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

[Charles Hill]

You pasted the show interface info, but I was asking for the show run interface info.

This is only one side of the link as well.  Both sides need to match.

Since duplex command is not allowed on a gigabit port on the 2960 switches, I would configure

int g0/24

speed 1000

and do this on both sides of the link.  If there is not a cabling issue, this should clear up the half duplex and change it to full duplex.

[Hansana Palihawadana]

First configure the speed as 1000, as the duplex is only considered after detecting speed of the interface. 

Then hard code the duplex as Full, then check the gi0/24 interface output you should be seeing 1000/Full.

Check for CRC or speed issues, if you are getting any error counters incrementing then reset the interface using clear interface gig0/24 command.

[Charles Hill]

According to the 2960 configuration guide,

Duplex command is not available on gig ports.

"You cannot configure half-duplex mode for interfaces operating at 1000 Mb/s.

You get a unrecognized command when you attempt to configure duplex on a 2960 gig port.

[jahanzeb.feroze]

But on rest of the ports, i am able to set duplex at full, without any issue,

here is the sh run of gig0/24 for you,

interface GigabitEthernet0/24
 switchport trunk allowed vlan 99
 switchport mode trunk
end

port info for the other end,(4500)

interface GigabitEthernet0/9
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 99
 switchport mode trunk
 speed 100
 duplex full
end

On other ports of 2960 (just to show u that i am able to config speed as duplex on other 2960 ports)

interface GigabitEthernet0/20
 switchport mode access
 shutdown
 speed 100
 duplex full

Please suggrst

[Charles Hill]

Change the 4500 end to

speed auto

duplex auto

and that normally clears up the half duplex issue.

If this helps, please rate.

[jahanzeb.feroze]

Thanks cehil, will try and get back to u .