Best Practices for OnPlus Device Discovery

mshikha · ‎07-19-2011

One of the most useful features offered by the OnPlus service is its ability to discover various devices on the network and display them in a logical topology diagram. The range and success of the device discovery process is affected by a few different factors and understanding them before installing OnPlus will ensure the best results.

How do I start Device Discovery?
What are the supported Discovery Protocols?
Is Device Discovery supported across VLANs and subnets?
Is Device Discovery supported across multiple sites across the WAN?
Where to place the OnPlus Network Appliance in the customer network?
Which devices are discovered automatically?
How do I proceed if a device is not discovered automatically?
How do I proceed if a device is displayed as Unknown?
Other Tips

How do I start Device Discovery?

Device discovery automatically begins when a customer is activated and it runs periodically. When a customer site if first activated, the portal will initially show ‘No discovery information currently available’. This is a normal part of the initial discovery process and depending on the size of the customer network, it will take a few to several minutes to display the topology.

Discovery is also triggered automatically when new devices are added to the customer site. If necessary, one can also manually trigger discovery as described in the link below.

Please note that login credentials will be needed to enable access to the device so that additional network devices can be discovered (for example, phones or other devices behind a managed switch or router).

Manually Triggering Device Discovery, page 53

Entering Device Credentials, page 81

What are the supported Discovery Protocols?

The OnPlus Network Agent uses a combination of standard and proprietary mechanisms to discover most devices on the network with an IP address such as Zeroconf, Cisco Discovery Protocol (CDP), Address Resolution Protocol (ARP), Simple Network Management Protocol (SNMP), Content Addressable Memory (CAM )tables and UPnP (Universal Plug and Play), Dynamic Host Configuration Protocol (DHCP) detection, Reverse Domain Naming System(DNS), NetBIOS Server Message Block/Common Internet File System (SMB/CIFS), Service Location Protocol (SLP) Windows Management Interface (WMI) and Internet Control Message Protocol (ICMP) (for monitoring).

Is Device Discovery supported across VLANs and subnets?

OnPlus can discover devices that are on the same VLAN/subnet as itself and also devices on other VLAN/subnets as long as OnPlus has access to a supported router which has visibility into the other VLAN/subnets. More specifically, OnPlus replies on the IP-MAC association, like that provided by an ARP table in a router or a layer-3 switch, to build out the topology.

Before a device can be recognized, OnPlus must have a MAC address to uniquely identify the device. The IP address, as provided by CDP for example, is also essential, but it is the IP-MAC association, as provided by an ARP table for example in a router or a layer-3 switch, that is key to the discovery process. OnPlus automatically gathers the ARP information for all the devices that are on the same VLAN or subnet as itself. However, for other VLANs and subnets, OnPlus must have access to a device that can report ARP information for those subnets and enable inter-VLAN routing. Switches generally do not operate at Layer 3 and so do not keep IP/MAC associations and so typically the device that can provide the necessary information is a router.

For a listing of currently supported Cisco routers and switches, please see the link below.

Cisco Device Feature Support

If you have a router that is not on this list but supports SNMP, you can also try to manually assign the 'Generic Managed Switch, SNMP v2/3' Device Driver through the process described below. Please make sure to populate the SNMP settings in the 'SNMP Access' tab.

Device Driver, page 86

Is Device Discovery supported across multiple sites across the WAN?

If there are multiple sites over the WAN, a separate OnPlus network appliance is recommended at each site. The appliance plays an important role in local tasks at each site such as receiving firmware over the WAN before sending that software to the device on the LAN and also taking configuration files from the device and pushing them to the cloud for archiving.

Another option is to manually add the devices to the topology as described in the link below. Manually added devices can be monitored just like any other device as long as the device has a static IP and a route exists between the OnPlus network appliance and the device.

Manually Adding Child Devices, page 65

Where to place the OnPlus Network Appliance in the customer network?

With the discovery process as explained in the previous sections, here are some guidelines in determining where to place the OnPlus Network Appliance in the customer’s network:

To ensure the most accurate and wide range of device discovery and topology representation, connect the OnPlus Network Appliance to a LAN port on an OnPlus-supported Cisco router or switch, upstream in the network. Please see the link below for a list of OnPlus-supported Cisco devices

Cisco Device Feature Support, page 203

Place the OnPlus Network Appliance on the LAN side of all devices in the customer network. For example, if a UC300 is deployed in an existing Small Business network behind an SA500 security appliance and the OnPlus Agent is placed on the WAN side of the UC300, discovery success and topology accuracy will be severely limited. In this scenario, place the OnPlus Appliance on the LAN side of the UC300

Which devices are discovered automatically?

OnPlus supports a growing list of Cisco devices designed for Small & Medium Business industry. These devices and several other non-Cisco devices that use standard discovery protocols are automatically discovered by OnPlus. For a complete listing of the supported Cisco devices and known limitations, please see the link below.

Cisco Device Feature Support, page 203

How do I proceed if a device is not discovered automatically?

In certain cases, some Cisco and non-Cisco devices are not automatically discovered by OnPlus because they do not broadcast their identity and information using the discovery protocols used by OnPlus or their discovery protocols are disabled for security reasons or by default. For such situations, OnPlus provides a way to manually add the devices to the site and carry out topology adjustments as described in the links below.

Please note that if the devices are behind a router, switch, or access point, login credentials of the parent device may be needed to complete the discovery. Once the device is added, an appropriate Device Driver may also be manually assigned to the device to enable collection of more information.

Once added, these devices can be remotely monitored just like supported devices as long as the device has a static IP and a route exists between the OnPlus network appliance and the device.

Manually Adding Child Devices, page 65

Manually Editing Device Connections / Re-parenting Devices, page 67

Device Driver, page 86

How do I proceed if a device is displayed as Unknown?

In some cases, a device may be successfully discovered, but gets marked as ‘Unknown’. This might occur when insufficient information is obtained from the device because the device does not advertise any of the supported discovery protocols or discovery protocols have been disabled on the device for security reasons or by default. In such cases, there are two choices to proceed:

For OnPlus Supported Devices - manually provide or assign an appropriate Cisco Device Driver to the affected device to enable discovery, as described in the link below

Device Driver, page 86

For Unsupported Devices - manually update the device name, category and description of the selected device in order to identify the device, as described in the link below

Settings, page 78

Other Tips

Non-CDP capable switches may flood CDP (Cisco Discovery Protocol) messages, resulting in inaccurate topology representation. To correct the topology, manually re-parent devices as described below.

Manually Adding Child Devices, page 65

Switches that are CDP-capable, but not supported by the OnPlus Portal will consume CDP messages from devices connected behind them. As a result, this limits the ability of the OnPlus Agent to see devices behind the switch if those devices use CDP as their only discovery method (for example, Cisco 7900 Series IP phones)

For Generic Managed Switches (non-OnPlus-supported Cisco devices and non- Cisco devices). These devices show up as Unknown Devices in the Topology (discovery for non-Cisco devices is not guaranteed). To identify these devices, enable and configure SNMP settings on the device, open the Device Information window on the portal and click the SNMP Access > Device Driver tab, choose 'Generic Managed Switch, SNMP, v2/v3', and click OK. Finally, go to the SNMP Access tab, enter SNMP settings, and click OK. After the next discovery cycle completes, any additional information that is discovered will be displayed, and the device icon will show “SNMP”.