[Index] [FineConnection web site]

How Error Control determines the root-cause of a "No response from device" event

Every time a device stops responding to status requests, EC verifies the status of all devices in the chain (network path) of devices from the ThisStation object to the device that stops responding. If one of the devices in the chain already has the "No response" status, Monitor one assumes this the root-cause of the event. In this case, the device that stops responding gets the blue tick.

If more than just one chain exists (because of network redundancy), Monitor one verifies all possible network paths!

In order to determine all possible network path(s) from the "ThisStation object" to a device, Monitor one needs two pieces of information:

1. Link or connection information (which device is connected to which other device)
2. If a device has more than one connected interface, does this device forward traffic? Does it route or switch packets or is the second interface just used for redundancy reasons and is it "hot-standby"?

Monitor one extracts link or connection information from the network map. It is therefore extremely important to draw network maps as factually as possible. The information whether or not a device forwards traffic comes from the definition of the Class each device belongs to (The checkbox This device forwards traffic via routing, switching, bridging or repeating on the Add/Modify a Class window). It is obvious that if you fail to set this option correctly, EC will not work as expected!

The list below shows some examples of device Classes that forward traffic.

• Routers, switches, hubs and/or repeaters.
• Firewalls.
• Modems.
• Wireless Access-points.
• Multi-homed Windows servers with running RRAS services (routing enabled)

The list below shows examples of devices with more than one connected interface that do not forward traffic

• Windows servers with more than one interface connected to one ore more switches, from which only one interface is active and the others "hot-standby".
• Servers in a SAN cluster that have an interface connected to the network and another interface connected to a fiber switch in order to access data on a central storage. The latter interface is not used for forwarding traffic but only for accessing the data on the central storage.