Znyx Networks bh5700 manual Network Connectivity Troubleshooting No Connection, External Fault LED

Network Connectivity Troubleshooting

No Connection

If the port LED is lit on the front panel, the switch has established a physical connection and the problem is a network configuration error. Check to see if both devices are configured to be on the same network (ex. 10.0.0.xxx) and that the subnet mask is set correctly.

Diminished Network Throughput

Depending on how the switch is configured, throughput problems can reflect configuration errors in the network topology.

If the Spanning Tree Protocol (STP) is not enabled, it is possible for broadcast loops to occur which can stress the network. The tcpdump (See the Ethernet Switch Blade User’s Guide for more information) utility is a widely used network troubleshooting tool which can display network traffic according to user-defined filters, which can help to troubleshoot problems such as broadcast loops. The tcpdump utility is included with the switch’s OA environment.

If STP is enabled, be sure to identify ports which were automatically blocked by the STP daemon to prevent broadcast loops.

A network diagram can be useful in isolating network loops.

Connecting to Devices with Fixed Port Speeds

Verify that switch and the connected devices are set to the same port speed setting, otherwise diminished or no connections can be made. If devices connected to the Ethernet Switch Blade are connected at a fixed Full Duplex, high error rates or sporadic connectivity can be observed. It is recommended that all devices connected to the Ethernet Switch Blade be set to auto-negotiate.

External Fault LED

The EXT FLT LED indicates that communications could not be established with one or more remote partner devices on an active port or ports. Ports which were configured to be up (via ifconfig), but do not have remote partner devices attached, can cause the EXT FLT LED to be lit, even if there are no hardware problems with the switch.

The OA zlc command can be used to check the status of individual ports and also to manipulate how the EXT FLT LED is managed (globally or on a per-port basis). By default, the EXT FLT LED is a global indicator. Use the zlc command to change how the LED is managed, to help isolate external fault indications to a particular port.

Before acting on an EXT FLT LED indication, make sure the configuration for the switch reflects how the chassis is populated with expected device configurations. For example, if a “default” configuration was used on the switch to bring up all ports on startup, but not all of those ports

Ethernet Switch Blade User's Guide release 3.2.2j page 170