Ethernet Port Hardware Troubleshooting


DATE:  August 27, 1999

PURPOSE:  This document describes the procedures to troubleshoot an ethernet hardware problem for Lucent PortMaster (TM) product models listed below:

Lucent Product Models: 

  • PM2 
  • PM2E 
  • PM2R 
  • PM2ER 
  • PM25 
  • IRX111 
  • IRX112 
  • IRX114 
  • IRX211 
  • PM3

SUMMARY:

Verify that the ethernet port is configured and dip switches 4 and 5 are set correctly. Try to ping other hosts on the network and check the arp cache. Verify that ethernet cables, hubs, transceivers, etc. are all functioning. Also try switching between ethernet types Bayonet-Neill-Concelman connector (BNC), 10-baseT and  Attachment Unit Interface (AUI).

TROUBLESHOOTING THE ETHERNET PORT

1) Verify that the ethernet port has an IP address on the same IP subnet as the rest of your network and that the netmask is also set to the same netmask as the rest of the network.

* To set the IP address and netmask issue the following commands:

Command: set address 192.168.0.1         
# sets the ether0 interface to 192.168.0.1
Command> set netmask 255.255.255.0       
# sets the netmask to a 24 bit, class C subnet

* To verify ethernet settings  issue the following commands

To check IP address and netmask:

Command> ifconfig
ether0: flags=16>IP_UP,IPX_DOWN,BROADCAST>
        inet 10.0.0.1 netmask ffffffc0 broadcast 10.0.0.0
        mtu 1500

Command> show ether0
  Ethernet Status: IP - Enabled   IPX - Enabled

   Interface Addr: 10.0.0.1
          Netmask: 255.255.255.192
Broadcast Address: 10.0.0.0

      IPX Network: 00000000
   IPX Frame Type: ETHERNET_802.3
 Ethernet Address: 00:c0:05:00:1c:19

          Routing: Broadcast, Listen (On)
     Input Filter:
    Output Filter:

2) Verify that sure the dip switches are set correctly for your Ethernet type.

(4 & 5) Sets the type of Ethernet connection.

        
Dip 4   Dip 5   Ethernet Type
--------------------------------------------------
Down    Down    Thin Net (BNC, Coaxial, 10-base-2)
Down    Up      Thick Net (AUI, Ethernet D)
Up      Up      Twisted Pair (RJ-45, 10-base-T)

3) Examine the IP routing table with the command> show route.  Verify that there is no static route for your local IP ethernet network. A bad static route will appear with the flag "NS", a good/normal entry for the ethernet network will appear with the flag "NL" with "ether0" as the interface. A static route overrides the natural route and  interferes with normal ethernet routing. To remove the route issue the following command replacing the x's with the IP address of your IP network (would appear as the destination in the routing table).

Command> del route xxx.xxx.xxx.xxx

4) From the Lucent router prompt ping another host on your network using the command listed below. If you get a reply that the host is alive you know you have configured the Lucent router properly. You can also try pinging the Lucent router from another host on your system. Try pinging 2 or 3 other hosts before moving on to the next step.

Command> ping xxx.xxx.xxx.xxx

ETHERNET LEDS

When using  the "ping" command it is normal to see blinking of the ethernet light(s) located to the left of the ethernet connections. The red light blinks "on" when network activity is detected. The green light is "on" when using 10base-T and there is connection to a hub.

5) If you are unable to ping another host on the ethernet check to see if you are getting Automatic Reverse- lookup Protocol (ARP)s.  ARP is the process of getting an ethernet address or Media Access Control (MAC) address of a host represented by an IP address. An unsuccessful ping will still produce an ARP request.  The output of the following command shows the mapping from IP address to MAC address in the ARP cache:

Command> show arp ether0
10.0.0.3 at 00:00:c0:cb:a6:44
10.0.0.10 at 00:00:c0:6f:19:5c

If  ARPs are seen as in the example above this  means the ethernet hardware is working properly, however,  there may be a configuration or routing problem.

6) Verify that your local network is not being overloaded. Use the following command to show the network interface statistics.

Command> show netstat

Locate the counts for IERRS (the number of input errors counted since reboot) and OERRS (the number of output errors counted since reboot), Collisions and resets.  Errors could indicate poor conductors (ie. bad 10baseT cable or connectors), Collisions greater than 3% of total output indicate an overloaded network or a ethernet hardware failure (cable, hub, nic, etc). Lot's of resets usually found in remote LANs indicates the router is not connected to an ether Local Area Network (LAN). To correct this, put dip switches 4&5 up for 10BaseT.

Excellent ethernet conditions:
Zero Collisions, Ierrs, Oerrs and Resets.

Good ethernet conditions:
Collision rate less than 1-5% and zero Ierrs, Oerrs and Resets.

Marginal ethernet conditions:
Collision rate between 5-10% and zero Ierrs, Oerrs and Resets.

Poor ethernet conditions:
Collision rate above 10% and single digit Ierrs, Oerrs or Resets in one day.

Bad ethernet conditions:
Collision rate above 10% and/or double digit Ierrs, Oerrs or Resets in one day.

Meltdown:
Collision rate above 30% and/or more than 1 Reset an hour with high rate of Ierros and Oerrs.

Resets indicate that an ethernet device Network Interface Card (NIC), hub, etc. may be defective and is flooding the ethernet. The Lucent router reacts to this flow of garbled data by resetting itself.

7) If you do not see anything in the ARP cache verify your Ethernet hardware. If you have a combination of Ethernet types then verify both. 

Use the command> show arp ether0  to view the ARP Cache table.

* For Twisted Pair (RJ-45, 10-base-T)
Swap out the following one by one and repeat steps 4 and 5.
- Swap Ethernet Cable with a known good  cable.
- Swap port on hub with a known good working port.
- Swap hubs.

* Thin Net (BNC, Coaxial, 10-base-2)
Verify the following hardware one by one and repeat steps 4 and 5.
- Verify that  you are using T-Connectors on all of your BNC ethernet connections.
- Verify that on the ends of the ethernet cable(s) terminators are being used.
- Swap T-Connectors.
- Swap Terminators.
- Swap your cables.
- Coaxial cables are know to have loose connections on the ends.  Verify that the cables are securely crimped into their connectors.

* Thick Net (AUI, Ethernet D)
Swap out the following hardware one by one and repeat steps 4 and 5.
- Swap out cables
- Verify that AUI transceivers have their Signal Quality Error (SQE) switch (if they have one) turned "off".
- Swap out transceivers.
- Verify that connections to the transceivers are secure.

8) If swapping out various ethernet hardware does not help try another ethernet type if  the resources are available. For example, if your 10-baseT does not work try coaxial, etc.  Repeat steps 4, 5 and 7.

NOTE: AUI and BNC are on the same ethernet bus on the network card and 10-baseT is on its own. Sometimes failures occur and 10-baseT will not work, however,  AUI and BNC will function, or vice versa. If this occurs call Lucent Technical support.

9) On rare occasions the dip switches may stick. Flip dip switches 4 and 5 up and down several times and reset them according to step 2. Repeat steps 4 and 5.

10) At this point if you are unable to ping and nothing is seen in the ARP cache check the hardware. This will require removal of the case.

CAUTION! If you need assistance contact Lucent Technical Support.
- Turn the Lucent router off.
- Unplug the Lucent router power plug.
- Disconnect all cables from the Lucent router.
- Locate the single screw on the back panel of the Lucent router. It is found top and center.
- Using a phillips screwdriver remove the screw.
- Use both hands give the case a slight jerk forward dislodging the case from the Lucent router.
- Visually inspect the ethernet daughter card mounted below the main board. Verify that it is securely mounted and that there is a connection between the Ethernet daughter card and the main board.
- Put the case back on the Lucent router.

If the Ethernet daughter card appears to be loose call Lucent Technical support.

11) If you are still unable to get the Ethernet hardware on the Lucent router to function call Lucent Technical support.