IntraVUE Scanner Discovery and Operation

Transcript

Welcome to the IntraVUE Discovery and Scanning Operations video. Before looking at the initial discovery of devices, let's understand more about the scanner. The IntraVUE scanner operates using several cycles. In every minute, the scanner will have one SNMP cycle and as many ping cycles as can be made before the next minute starts. The scanner must be able to complete at least one SNMP cycle and one ping cycle in each and every minute.

In the SNMP cycle, the scanner processes the previous responses, gets interface speed, gets transmitted and received byte counts, gets basic data like name, description, location, et cetera, and gets a quota of the data needed from managed switches. In the ping cycle, the scanner processes the previous data, pings all known devices, pings a quota, typically 20, of the devices which have never responded to a ping. There are typically four to seven ping cycles per minute, depending on speed.

There's also an SNMP scan complete cycle. The scanner is collecting a little data from managed switches in each minute. It usually takes a couple of minutes to get all of the managed switch data from a switch. The SNMP scan complete cycle is over when the switch that required the most questions has been completed. Near the end, it is probably the only switch being queried. Once the SNMP scan complete cycle is complete, the scanner will compare the data from this cycle to the previous cycles.

The data may result in a device being moved from one port to another port of a different or the same switch. If there is conflicting data, the scan will wait until the next scan cycle to resolve the conflict. An example is a device moving to a new switch and being reported by the new switch, but the old switch has not finished flushing the data out of its MAC table. Now, let's go to when the scanner starts discovering a new network.

So we're going to save this one. Go to view the topology. As soon as a device responds, it will be put under an unresolved node, and an event will be created. This lets the user know that the device is reachable, but it will still take more time for the scanner to get its MAC address. Here we see five devices discovered and under unresolved. The scanner needs the device's MAC addresses so it can locate the device under a managed switch.

These MAC addresses come from the top parent's ARP cache, so it is important to use the right one. As soon as the MAC address is discovered, the devices will move from unresolved to the top parent, and a new event created with the MAC addresses. Now all devices have moved from unresolved to the top parent. The scanner is trying to tell if any of the discovered devices are managed switches from their SNMP.

If you find any devices that are connected but stay under the unresolved node for hours, the wrong top parent may have been selected. A special but common case involves managed switches which are remote and outside top parent's netmask. Since their MAC will not be in the ARP data, a special checkbox in device edit will tell the scanner to use the MAC address provided by the switch's SNMP. This control is available under the SNMP section.

Check to enable Use SNMP Provided MAC for L2 Switch. Now you see two devices have been recognized as managed switches, and the other device is moved to ports on those switches. Hovering over the lines will show you the port numbers from and to. This is the end of this video. The next video will cover initial setup, configuration, and maintenance steps.