Network Notepad CDP Tool: Quick Guide to Discovering Cisco DevicesNetwork administrators often need a fast, reliable way to discover and visualize devices on a local network. The Network Notepad CDP Tool provides an accessible, Windows-friendly method for extracting Cisco Discovery Protocol (CDP) information and turning it into useful topology maps. This guide explains what the tool does, how it works, and how to use it effectively — from installation through advanced tips for troubleshooting and security considerations.
What is Network Notepad CDP Tool?
Network Notepad CDP Tool is an extension/plugin for Network Notepad (a Windows diagramming and network mapping application) that collects CDP data from Cisco devices and imports it into Network Notepad for automated topology construction. CDP (Cisco Discovery Protocol) is a Layer 2 protocol Cisco devices use to advertise device identity, capabilities, and directly-connected neighbors. The plugin automates the process of querying devices and building a preliminary topology, which administrators can then refine visually.
Why use CDP for discovery?
- Accurate local topology: CDP reports directly-connected neighbor relationships, making it ideal for mapping Layer 2 connections.
- Device detail: CDP provides device type, platform, IP address, local interface, and sometimes software version — useful for documentation and inventory.
- Low overhead: CDP runs on the devices and only exchanges small periodic packets; querying via CDP is lightweight compared to full SNMP walks.
Prerequisites
- A Windows system with Network Notepad installed (Community or Professional editions may support plugins differently).
- Administrative access to a PC with network reachability to the devices you want to query.
- Credentials for devices if the plugin requires SSH/Telnet/CLI access. Some CDP retrieval methods may use SNMP or SSH; confirm what the plugin expects.
- Cisco devices with CDP enabled (it’s enabled by default on many IOS versions but may be disabled in hardened environments).
Installation and setup
- Download Network Notepad and install it from the official site if not already installed.
- Obtain the CDP Tool plugin that matches your Network Notepad version. Plugins may be distributed as .dll or packaged installers.
- Place plugin files into the Network Notepad plugins folder (typically within the program installation directory) or follow the plugin’s installation instructions.
- Restart Network Notepad so it recognizes the plugin.
- Open the plugin panel or menu entry — there should be an entry like “CDP Tool” or “Device Discovery.”
Configuring the CDP Tool
- Add starting IP addresses or seed devices: specify one or more managed devices where the tool should begin querying.
- Authentication settings: enter device credentials if the tool uses SSH/Telnet. For SNMP-based retrieval, supply community strings or SNMPv3 parameters (username, auth/privacy settings).
- Discovery options: set recursion depth (how many hops to follow), timeouts, and whether to query only for CDP or to combine with SNMP for additional details.
- Output preferences: choose whether results should automatically populate the current diagram, create new nodes, or export to a file (CSV, JSON, etc.).
Running discovery
- Start with a single seed device that is well-connected to the network core (for broader discovery).
- Launch discovery — the tool will query the seed for CDP neighbor tables.
- For each neighbor discovered, the tool will optionally query that device and repeat until the recursion limit is reached.
- Results are added to the Network Notepad canvas: devices become nodes, and CDP-reported interfaces create links between nodes.
- Review the auto-generated map and tidy up labels, icons, and layout manually as needed.
Interpreting results
- Device nodes typically include hostname, platform, management IP, and local interface used for the connection.
- Link labels indicate local interface → remote interface pairs (e.g., Gig1/0/1 ↔ Gi0/1).
- If devices are missing, ensure CDP is enabled and that network segmentation (VLANs, access-lists) or management ACLs aren’t blocking queries.
- Some devices (non-Cisco or misconfigured devices) won’t appear because they don’t speak CDP — LLDP may be present instead.
Combining CDP with SNMP and LLDP
- SNMP can supplement CDP by pulling interface descriptions, serial numbers, asset tags, and more granular inventory details.
- LLDP (Link Layer Discovery Protocol) is a vendor-neutral alternative; if your network has mixed vendors, enabling LLDP alongside CDP can yield fuller topologies.
- Many discovery workflows use CDP for Cisco-to-Cisco links and LLDP/SNMP for cross-vendor discovery and attribute enrichment.
Common issues and fixes
- No neighbors found: verify CDP is enabled on devices (show cdp neighbors) and that the management IP is reachable.
- Partial topology: increase recursion depth or add additional seed devices.
- Incorrect interface mappings: CDP reports the interface as seen by the device — verify duplex/speed mismatches or use SNMP if labels are missing.
- Authentication failures: double-check credentials and try alternative access methods (SNMP vs. SSH).
Security and operational considerations
- CDP exposes device platform and connection details — consider limiting CDP on edge ports or where exposure to untrusted devices is possible.
- Use read-only SNMP community strings and SNMPv3 with authentication/privacy where possible.
- Run discovery during maintenance windows if your tools perform active logins or generate noticeable management traffic.
- Keep the discovery tool and Network Notepad updated to reduce plugin compatibility and security issues.
Advanced tips
- Export discovery results (CSV/JSON) and feed them into asset databases or CMDBs for automated inventory updates.
- Use custom icons and templates in Network Notepad to reflect device roles (switch, router, wireless controller).
- Combine with traceroute and ping sweeps to validate reachability beyond CDP’s Layer 2 visibility.
- Schedule periodic discoveries to catch topology changes; compare exports over time to detect drifts.
Example workflow (concise)
- Install plugin, configure credentials and seed IPs.
- Run CDP discovery from a core switch IP, with recursion depth 3.
- Export results to CSV and load into CMDB.
- Manually refine the Network Notepad diagram for presentation.
When not to rely on CDP alone
- Networks with many third-party devices (LLDP needed).
- Environments where CDP is intentionally disabled for security.
- When you need routing-level topology (use routing protocol data and traceroutes).
Conclusion
The Network Notepad CDP Tool is a practical, low-overhead way to discover Cisco devices and quickly build visual topologies. It’s most effective when combined with SNMP and LLDP for attribute enrichment and cross-vendor visibility. Use proper credentials, limit CDP exposure where needed, and integrate discovered data with inventory systems to get long-term operational value.
Leave a Reply