Scitex Network Services Group

Basic LANMeter Network Troubleshooting

David Zolotko
May 23, 1999

• Procedure
• Testing for IP Problems
• No Problems
• Problems Found
• Switching Hub Data
• Hub Test
• NIC Test
• ExperT-Autotest
• Shared Ethernet Segment Tests
• Local Hosts
• Cable Tests

This document will help you with the basic troubleshooting features found on the Fluke LANMeter. For additional in-depth information on advanced features, feel free to consult the Fluke Enterprise LANMeter Users Manual.

Procedure

1. If needed, connect LANMeter to AC power.
2. Power unit on and after the unit is booted; check to make sure it is configured for 10/100 BaseT by pressing the "Setup/Utils" button. The following menu should appear:



3. Should you need to adjust a setting, do so by highlighting the "Connector type" or "speed," then toggle your choice using the appropriate left/right arrow buttons.

Configuring the LANMeter for IP

4. Overview: The IP Auto Config feature will help you with configuring the local subnet and mask. Using the "Assisted Mode" option, you will have to guess at the last octet of the IP address. After you enter your choice, the LANMeter will search the subnet for a duplicate IP. If none is found you can save this as your complete IP configuration for the subnet you are currently on.
5. Press the "EXIT/STOP" button until you arrive at the main menu:

   

   5b)Connect a known good category 5 rated patch cable between the LANMeter RJ45 socket labeled:

   "TO HUB" and the network hub (not a cross over cable).

   5c) Press the "Internet TCP/IP" button. You should see a similar menu:

   

   5d) Press the "IP Auto Config" button. Using the left/right arrow buttons, toggle the "Discovery Mode" setting to the appropriate choice if the site happens to be using a DHCP or BOOTP server. In the majority of the sites the "Assisted" mode will be your choice:

   

   5e) Press the "ENTER/RUN" button. The LANMeter will now search the network for available subnet info. It will display the first three octets of the IP subnet and prompt you for your choice of the last octet:

   

   5f) Enter 254 (or your guess at an unused address) and press the "ENTER/RUN" button. The LANMeter will then search the network to see if it can use your choice. If that address is in use, you will get an "ERROR!" message. Repeat this process until it completes:

   

   5g) Press the "Save Config" button.

Testing for IP Problems

6. Press the "EXIT/STOP" button until you arrive at the main menu. Select the "Internet TCP/IP" button. Then select the "Segment Discovery" button. To run the "Segment Discovery" test, confirm your choice with the "ENTER/RUN" button.

   Put the LANMeter down and take a coffee break. The LANMeter will run a suite of tests repeatedly. Let this test run for 15 minutes to discover the IP configuration and any possible problems.

   No Problems

7. If the network has no initial IP problems, you should see a screen similar to this:

   

   Troubleshooting continues by highlighting a menu item that has the · next to it. See the corresponding sections in this document

   Problems Found

8. If a major problem is found with the IP network structure, you should see a screen similar to:

   

   Using the up/down arrow buttons, highlight the "· Problems:" menu and press the "ENTER/RUN" button.

9. The screen now will display what problem was found. A common problem found during most site visits is that multiple devices on the network have duplicate IP addresses. This is very common with sites that have HP network printers since HP assigns a default IP address to each unit during manufacture. If this is the case, your screen will show something similar to:

   

   In the above example, The screen is indicating that two network interface devices manufactured by HP are assigned the same IP address; and a network interface device manufactured by 3Com has the wrong IP subnet in its address (192.009.100.003 vs. 192.000.000.003)

   Switching Hub Data

10. Overview: Only network devices that have SNMP intelligence can be accessed by the LANMeter. Some of the cheap lower end products do not support this feature so don't be alarmed if you can't get any data from them. This data is usually public information; that is to say no restrictions have been programmed into the device to hide this data. The LANMeter queries the SNMP agent in the device with a community string called "PUBLIC" to get the data. Some sites may have this data protected with a renamed community string. If so, and you know the new name, you can access the data by configuring the LANMeter with the new community string name. If you don't know the new name you will not have access to this data. [CoreBuilder 5000 switches require: public@vbridge_x (x= virtual bridge #)]
11. From the "Segment Discovery" menu, SNMP data from switches can be accessed by highlighting either:

    • Switches/Bridges:

    • SNMP Agents:

    

    • Note: Any device that supports SNMP including some workstation NIC cards can respond to the SNMP requests, along with network devices such as switches and routers.
12. Highlight the device you wish to get SNMP data from and press the "ENTER/RUN" button.

    To view a description of the device, select the system group menu:

    

13. To view network statistics from the device you have selected, select menu item #2: "MultiPort Stats / SwitchWizard"

    Network traffic statistics, sorted by port number, will display on screen. For troubleshooting purposes, you can sort the statistics by errors or utilization. Press the "Sort Options" button and select your choice.

    

    Now highlight the port number you want detailed data on and press the "Stats Details" button. The screen will now show you a list of all the MAC addresses that are residing on that port. In this example, port 9 is the downlink to another switching hub that supports other network nodes. Scroll down to get a look the rest of the list.

    

    To view the port statistics in detail, press the "Interface Stats" or "Interface Errors" buttons:

    

    The interface stats menu will show you the average values during the sampling period as well as the peak values recorded. Total frame counts and percentages are on the right. High error counts can be further diagnosed by examining the hub port and network interface card of the workstation. Use the following tests to check hub ports and NICs. Hub Autotest when completed can be drilled down to expose protocols found on the port.