Link to home
Start Free TrialLog in
Avatar of akyuen
akyuen

asked on

unable to set full duplex 100 on WAN interface

Hello,

I've noticed lots of collisions and late collisions on our WAN interface of our Cisco ME 3400 switch.  Our ISP says that they've configured their interface to 100 full duplex.  The WAN interface is connected to our ISPs switch and  it's configured to 100 half duplex.  For some reason, when I configure the WAN interface to 100 full duplex, the interface shuts down.  When I set it to Auto, it configures itself to 100 half duplex.  The ISP's switch is a Ciena 3930.  If I connect a laptop with our internet address and connect it to the Ciena, I can get full duplex.  Below is the configuration of our WAN interface.  Any ideas why I can't set it to full duplex?

FastEthernet0/4 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is
Internet address is x.x.x.x/x
MTU 1500 bytes, BW 100000 kbit, DLY 100 usec,
         reliability 255/255, txload 2/255, rxload 83/255
Encapsulation ARPA, loopback not set
keepalive set (10 sec)
Half-duplex, 100Mb/s, media type is 10/100BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang 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 32659000 bits/sec, 5578 packets/sec
5 minute output rate 1092000 bits/sec, 1359 packets/sec
      231404249 packets input, 232076754647 bytes, 0 no buffer
      Received 650 broadcasts (0 IP multicasts)
      0 runts, 0 giants, 0 throttles
      2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
      0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     142056890 packets output, 33746945779 bytes, 0 underruns
      0 output errors, 11643061 collisions, 0 interface resets
      0 babbles, 1022803 late collision, 0 deferred
      0 lost carrier, 0 no carrier, 0 PAUSE output
      0 output buffer failures, 0 output buffers swapped out
Avatar of Predrag Jovic
Predrag Jovic
Flag of Poland image

By default, if auto negotiation is turned off on one side, other side will be auto-configured as half duplex. Collisions and late collisions are result of duplex mismatch. I have no idea why port shut itself, typically it never happens.
Did you try just to configure duplex (full) and let switch negotiate speed?  - this sometimes can solve problem
Did you try to use some other port?
SOLUTION
Avatar of arnold
arnold
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
ASKER CERTIFIED SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
It is quite absurd from your 'provider' to disable auto-negotiation.
For business users, connection to ISP from my experience duplex and speed are typically set manually. Speed still should be able to be negotiated if one side is manually set, but there should be no duplex mismatch with manually configured duplex on both sides. The reason for manually configuring duplex is occasional duplex negotiation when both sides are configured as auto (one or both sides fail back to half duplex).

Additionally, Author may try to replace cable between devices.
@gheist - SPs do it regularly.  It's easier to enforce speeds based on the physical port characteristics rather than policing, etc.

You have some input errors on the interface so change the cable and see if it settles down at 100/full.
Avatar of akyuen
akyuen

ASKER

So far the things I've tried to troubleshoot unsuccessfully are:

1) replacing the network cable.
2) setting duplex and speed values to auto. (interface configures to 100 half)
3) setting duplex at 100 and speed to auto. (interface shuts down)

I hooked up my laptop to the ISP's Siena router and manually configured the NIC on the laptop to 100 full --  no problems with the connection.

I'm going to try to configure another interface on my L3 switch and see if it works.  Since this is layer 3, all the interfaces must have unique IP addresses, correct? Can I simply shut down the current WAN interface and program the WAN ip into another interface?
No, IP is not set in the port. Level 3 means it can have and does routing when needed/configured.
All devices connected to any flat network have to be unique.
You have to see if your switch is routing, then defining a new port in a similar way to the current one will be enough to then move from one to the other.
Avatar of akyuen

ASKER

I configured another port with the exact same settings and had the exact same result -- the port shuts down when it's configured to 100 full.  The only way the port connects is if the setting is configured to 100 half.
Most likely it is a bug. You have on the link above also long list of bugs regarding speed and duplex on devices (some devices do not cooperate well with each other).
Gave you checked with the ISp to confirm whether they really fixed their side to 100full.
If so, ask them to change it to auto and see what the results are.