Physical segment is a map automatically generated and updated by NetCrunch that represents the physical connections between computers and manageable switches (Level 2 devices that support the Bridge MIB [RFC 1493]) of local or remote networks.
Building the physical topology
Building the physical segments topology is always accomplished by processing of forwarding tables and optionally by additional analysis methods, such as: Spanning Tree Protocol (STP) and Cisco Discovery Protocol (CDP).
A wizard is provided to assist you in this task. In the wizard you can add other Layer 2 devices and also edit the default physical segments layout characteristics to fit your needs.
Physical segments map setting window
Once the physical segments map is created you can display its settings. Click the Menu icon in the right upper corner and select Properties or right-click within the map area and select Map Properties from the pop-up menu. Physical Segments Map Settings window displays.
Using the Physical Segments Map Settings window you can:
- Change the analysis method.
- Hide Inactive Nodes - by default, NetCrunch is trying to remember the last position of all nodes. If this check box is selected, the down nodes will not be shown on Physical Segments Maps.
- Data Refresh Time - this field specifies the time interval when NetCrunch will collect information about the physical topology of the monitored atlas. In this field the user can specify a different time for refreshing all physical segments in the monitored atlas from the time of monitoring services. Since the topology of physical maps is not changing frequently it is suggested to define a longer period. All maps in the Physical Segments section of the Atlas Maps window will be updated if any change has been discovered.
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Edit Map Layout options such as:
- Port Name Style - this field specifies the style of the port name on maps.
- Port Box Style - this field specifies the style of the port shape on maps.
- Sort Ports By - it allows sorting ports by number or name.
Connection lines
Connection lines drawn on physical segment maps represent physical connections between bridges and other devices. The red color of the connection line indicates that one of the connection ports (or interfaces) is in the down status. By click on the selected line on a physical map and choose Current Traffic And Status option from context menu the Connection Status window is opened with information about the interface properties and input/output data of both connected devices, displayed on separate tabs.
Note: If the physical segments topology structure created by running the wizard does not completely reflect your network, you can later add your own Level devices.
While refreshing physical segments NetCrunch is gathering information about network topology of the monitored atlas. Therefore, additional network traffic is generated during this process.
It is not suggested to select the CDP or SNMP option if not all switches in the network support these protocols. Otherwise, the physical maps my be drawn incorrectly.
