VLAN and connectivity monitoring in NetCrunch
Use NetCrunch to see where nodes are connected and to which VLAN they belong.
Scenario
VLANs in modern networks are quite common, as they are a flexible way of isolating particular network segments for protection from unauthorized users who can be thus restricted to selected network segments only. NetCrunch can display VLANs, show which nodes are connected to each of them, and it will do it automatically, no manual configuration needed!
Pre-requisites
The only pre-requisite is to have the Physical Segments feature enabled - therefore SNMP must be enabled on switches. No more configuration is needed, everything is discovered and drawn automatically by NetCrunch.
VLANs
When VLAN information is read by NetCrunch, it will be displayed in a few places.
Atlas Tree:
A dynamic folder named VLANs will be created in the Atlas tree - depending on the size of network it may be required to scroll down atlas tree. It will contain all VLANs detected. Based on VLANs' names, dynamic views will be created with nodes that are included in each of those VLANs.
Nodes table:
Nodes view can be shown for any atlas view. In this case, Network Atlas will be used:
- Select Network Atlas in the atlas tree
- Switch to the Nodes tab
- Click on the drop-down menu next to the Layout and select Layer 2
In the result, the layout switch view shows a group of nodes and to which VLAN they belong, additionally it will show another useful information - how the devices are connected - therefore it's a great way to introduce a new administrator to the network' structure.
Port Mapping:
If there are VLANs on the switch device, you will see them in Node Status Port Mapping In this view, you can check which nodes belong to the given VLAN and to which ports they are connected. You can even see nodes that are not in Atlas here.
Alerts on performance counters related to VLANs
It is possible to set alerts on performance counters related to VLANs in NetCrunch. To do this, please follow the steps below:
- Open Node Settings on any switch, which has configured VLANs
- Click on Custom tile in SNMP Section
- Click + Add Alert button
- Select
New Event for Performance Counter - Click
- Check
Select from counter libraryradio and click Next - From the
Performace Objectdropdown, please selectInterfaces - From the
Counterslist please select counter which you are interested in, e.g.Error/sec - From the
Instancelist you can select VLANs (or ports) from this switch - Click ADD
- Set condition and save the configuration
From now on, NetCrunch will check for you if the event occurs and alert you if the condition is met.
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