LanTopolog

LanTopolog is a freeware application that provides physical network topology discovery, visualization and monitoring
Key features:
- Automatic physical network topology discovery based on SNMP
- Provide detailed and searchable physical network topology map so you can quickly isolate network connectivity failures
- Topology views show which network devices are connected to each switch port; port connections are labeled with port numbers
- Ability to auto-discovery new devices at they are added to your network
- LanTopolog also includes network monitoring tools
- Monitoring device's state (active/inactive) in real-time using ICMP
- Generating alarms when there are failures in the network.
- E-mail alerts notifying
- Web browser-based access from anywhere in the network
- Easy-to-use interface
From the program site you can download the shareware version LanTopolog 2.xx
that has additional features.