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    Troubleshooting Notes for the Express 100BASE-TX Switching Hub

    
    

    TROUBLESHOOTING NOTES FOR THE EXPRESS 100BASE-TX SWITCHING HUB

    
       Troubleshooting Notes from Tech Support for the Express 100BASE-TX
    
       Switching Hub
    
    
    
       Connecting to a 10 Mbps segment
    
    
    
         The Express Switching Hub is a 100 Mbps-only switch. You can't connect
    
         a 10 Mbps device directly to the switch.   
    
    
    
         The preferred way to connect the a 10 Mbps segment or device to the
    
         Express Switching Hub is by using the Intel Express 10/100 Downlink to
    
         connect 10 Mbps segments or devices to an Express 100BASE-TX Stackable
    
         Hub or Switching Hub. The Express 10/100 Downlink is a 2 port switch
    
         with each port running at 10 Mbps or 100 Mbps.
    
    
    
         Another inexpensive alternative is to using the Express 10/100
    
         Downlink is to connect the segments through a server. Several adapters
    
         on the market (such as the Intel EtherExpress PRO/100 adapter) operate
    
         at either 10 or 100 Mbps. By connecting the Express 100BASE-TX
    
         Stackable Hub to one server adapter at 100 Mbps and your 10BASE-T hub
    
         to a separate adapter at 10 Mbps in the same server, you can route
    
         traffic from the 10 Mbps segment to the 100 Mbps segment through your
    
         Network       Operating System (NOS) like Novell NetWare or Windows NT
    
         3.51.
    
    
    
         If your NOS doesn't support multi-protocol routing (Windows 95
    
         peer-to-peer and Windows for Workgroups* don't), you must use a Fast
    
         Ethernet switch or router that supports both 10 Mbps and 100 Mbps. 
    
    
    
         Note:  Window NT* 3.51 doesn't include the multi-protocol router
    
         software by default. You can download it from the Microsoft World Wide
    
         Web site.
    
    
    
       Straight-through vs. crossover cables
    
    
    
         Ports on the switch are wired MDI so you can use a straight-through
    
         cable when connecting to a Fast Ethernet* repeating hub port, which is
    
         usually wired MDI-X. For direct connection to another MDI port
    
         (workstation,  server, or another switch), you must use a crossover
    
         cable.
    
    
    
       Downloading the Intel MIB (Management Information Base) file
    
    
    
         The MIB filename is SWCH1MIB.EXE. You can find the file on Intel's
    
         Customer Support web site (http://www-cs.intel.com) or the Intel BBS
    
         (see the inside back cover of the User Guide for phone numbers). 
    
    
    
         Note: Be sure you assign an IP configuration to the switch before
    
         using it with an SNMP-compliant network management system (NMS). See
    
         the Quick Start section in the User Guide for more information.
    
    
    
         See your NMS documentation for instructions on compiling the MIB for a
    
         new device.
    
    
    
       Lost or Forgotten Password
    
    
    
         If the password is lost to the Administrative Interface, there is a
    
         back-door which allows the network administrator to log in.  Simply
    
         type "debug" at the password prompt, with any user name.  Once at the
    
         console prompt, the user must reset the device to its factory defaults
    
         to clear the password using init-nvram.
    
    
    
       Troubleshooting the Express Switching Hub
    
    
    
       If there is an operating problem with the Express Switching Hub,
    
       incorrect configuration or cabling is probably the cause. Try the
    
       troubleshooting steps below in order:
    
    
    
         1.  Verify that your cables are wired correctly. This is the most
    
         common problem. Use a UTP crossover cable to directly connect another
    
         switch, server, or workstation to the switch. Use a straight-through
    
         cables when connecting to a repeater. See page 8 for more information.
    
    
    
         2.  Make sure the unit is plugged into a grounded, functioning AC
    
         outlet providing between 90 VAC and 264 VAC at 50/60 Hz. 
    
    
    
         3.  Review the Link LEDs of other devices to ensure that those ports
    
         you believe should be functioning are properly attached to the switch
    
         with a Category 5 UTP cable.
    
    
    
         4.  Review the switch's Link LEDS to ensure that ports you believe
    
         should be functioning are properly configured, and not disabled or
    
         partitioned. 
    
    
    
         5.  If you configured a port for full duplex, make sure the device on
    
         the other end is configured for full duplex and is capable of
    
         transmitting in full duplex. Remember, you must have a point-to-point
    
         connection for a full-duplex link. Most repeaters aren't capable of
    
         full duplex. 
    
    
    
         6.  If the FC/FD LED shows excessive activity, see Chapter 1 for
    
         recommendations on dealing with excessive flow control.
    
    
    
         7.  Make sure that the equipment attached to the switch is properly
    
         configured. If the CLSN LED is on continuously, you may have a problem
    
         with an adapter on the segment.
    
    
    
         8.  Use the Console Manager to check the switch's status. Use the
    
         sys-stat command to check the overall system status and the
    
         get-port-cfg command to check the status of each port. 
    
    
    
         The EXPRESS 100BASE-TX SWITCH is a highly reliable unit. If there are
    
         any operating problems, the fault probably lies in some other aspect
    
         of the configuration. However, certain steps may be taken to ensure
    
         that the unit is functioning normally.
    
    
    
         The most common problem is a cabling problem.  Review all link LED's
    
         to ensure that those ports you believe should be functioning are
    
         properly attached to a cable.  It is important to verify that cables
    
         are wired correctly; i.e. use a UTP crossover cable to directly
    
    
    
         connect another switch or any other MDI type-device (such as a
    
         workstation) directly to a port.  
    
    
    
         If a workstation is unable to transmit or receive, review all link
    
         LED's to ensure that those ports you believe should be functioning are
    
         properly configured, and not disabled or partitioned. If the suspect
    
         ports are disabled or do not seem configured properly, re-configure
    
         the port through SNMP management or the Administrative Interface. 
    
         Review the port configuration, the Spanning Tree configuration, the
    
         virtual LAN configuration, and any custom filters which may affect the
    
         malfunctioning station.  In addition, review all Full Duplex LED's to
    
         ensure that those ports you believe should be functioning are in the
    
         correct mode of operation.
    
    
    
         If the Flow Control LED shows excessive activity, or there are
    
         excessive collisions on the network, then the most likely cause is
    
         either poor network configuration, or simply too many devices on the
    
         network.  The second case simply requires an upgrade in the network
    
         (adding a switch or, perhaps, a router).  The first case is more
    
         difficult to solve, and depends on the traffic patterns.  Management
    
         software should be used to isolate the source of the collisions, and
    
         the switch forwarding statistics should be checked to determine which
    
         port(s) are over-flowing. 
    
    
    
         If the switch has no power, i.e., the LED's do not function, then the
    
         fuse should be checked and replaced with the correct fuse type.  The
    
         power specifications for the EXPRESS 100BASE-TX SWITCH are: between 90
    
         VAC and 264 VAC at 50/60 Hz.
    
    
    
         Under certain circumstances, it is necessary to reset the
    
         Administrative Interface to the factory defaults.  To do this, simply
    
         log in, and type "init-nvram" at the console prompt.  Then, type
    
         "warm-reset" to reset the device.  The factory defaults will be
    
         reinstalled. 
    
    

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