7UPS Network Management Card 2 User’s Guide
Watchdog Features
Overview
To detect internal problems and recover from unanticipated inputs, the Management Card uses internal,
system-wide watchdog mechanisms. When it restarts to recover from an internal pr oblem, a System : Network
Interface restarted event is recorded in the event log.

Network interface watchdog mechanism

The Management Card implements internal watchdog mechanisms to protect itself from becoming
inaccessible over the network. For example, if the Management Card does not receive any network traffic for
9.5 minutes (either direct traffic, such as SNMP, or broadcast traffic, such as an Address Resolution Protocol
[ARP] request), it assumes that there is a problem with its network interface and restarts.

Resetting the network timer

To ensure that the Management Card does not restart if the network is quiet for 9.5 minutes, the Management
Card attempts to contact the default gateway every 4.5 minutes. If the gateway is present, it responds to the
Management Card, and that response restarts the 9.5-minute timer. If your applicati on does not require or have
a gateway, specify the IP address of a computer that is running on the network and is on the same subnet. The
network traffic of that computer will restart the 9.5-minute timer frequently enough to prevent th e Management
Card from restarting.
Flashing green The NMC is receiving or transmitting data packets at 10 Mbps.
Flashing orange The NMC is receiving or transmitting data packets at 100 Mbps.
Condition Description