The Neighbor Map gadget is used to discover devices on your network using Cisco Discovery Protocol (CDP) and Link Layer Discovery Protocol (LLDP).
Cisco Discovery Protocol (CDP)
CDP is a Layer 2 network protocol created by Cisco Systems, and is used to broadcast and collect information about Cisco devices including routers, bridges, access servers, and switches connected to a specified network device. Devices broadcast CDP announcements to a multicast destination. By default , these announcements are sent every 60 seconds through interfaces that support Subnetwork Access Protocol (SNAP) headers such as Ethernet, Frame Relay, and ATM.
Every CDP device stores the data received from other devices in a table that is held until the holdtime timer expires (default of 180 seconds). Accessing this information on each device enables you to query each host and then create a network topology map.
Link Layer Discovery Protocol (LLDP)
LLDP is a multivendor, Layer 2 protocol that gives network devices permission to broadcast their identity and device information to the rest of the local network. LLDP works similarly to CDP, but is used across a large variety of vendors instead of being limited to Cisco devices. Information obtained using LLDP is stored on the network devices in a table that can be accessed using SNMP. Accessing this information on each device enables you to discover each host and create a network topology map.
The Neighbor map gadget can use one or both of these protocols to draw a topology map of network devices connected to a specific target device or group of devices. The map displays each device and the associated interfaces used to connect to neighboring devices.
The announcements sent by each device using CDP or LLDP include a variety of information about the device. The data can include the operating system version, host name, IP address, the port identifier from which the announcement was sent, device enter and model, and more.
The CDP and LLDP information is obtained from each device using SNMP. Neighbor Map attempts to discover device credentials for any device that has not been added to Workspace Studio using the credentials database.See Add device credentials.
Map neighbor devices
- Click Gadgets > Tools > Discovery Tools, and then drag the Neighbor Map gadget to a tab.
- To configure the gadget with devices that have already been added to Workspace Studio, drag your devices from the Devices tab on the explorer pane to the Hosts field.
- To configure the gadget with a device that is not in the explorer pane, enter the IP addressorhost name of the device you want to target in the Hosts field.
- Select or enter the number of hops you want to scan in the Hop Count list.
- To modify the settings of the Neighbor Map gadget prior to creating your map, complete the following:
- Click , and then click Gadget Settings.
- From the Discovery Protocol list, select the protocols you want to use.
- Enter the maximum number of neighbor discoveries that can be outstanding at a specific time in the Maximum Outstanding Discoveries field.
- Click the ICMP Settings tab.
- Adjust any of the ICMP settings you want to change
- To use a custom ICMP packet payload, enter the ICMP packet payload string you want to use in the ICMP Packet Payload text box.
- Click OK.
- Click Create Map.
- If you want to export your neighbor map, complete the following:
- Click , and then click Export Map.
- Enter a file name, and then select a file format from the Save as enter list.
- Click Save.
- Creating a map can take several minutes to complete depending on the number of target devices and the number of hops you have configured.
- When mapping a CDP-only network, mapping time is significantly increased when you have Neighbor Map configured to scan both CDP and LLDP.
- After the neighbor map has been created, you can use the Zoom list, Zoom to Fit, and Perform Node Layout controls above the map to adjust the layout of your map.
- When mapping two or more devices that use different protocols, the neighbor map will display the devices separately even if they are physically connected. This is because CDP (a proprietary Cisco protocol) and LLDP do not share any information.