How NetBrain Accesses Network Devices for Major Functions
Many NetBrain functions such as the live network discovery, benchmark, path discovery and monitoring require access to the Live network. In order to support the operations, Netbrain requires the following information configured within the NetBrain platform:
- Username/password pairs and privilege passwords — Devices credentials used to remotely connect to devices using Telnet/SSH and retrieve live data via CLI commands or API requests.
- SNMP RO strings — used to access devices via SNMP. Monitoring devices also requires SNMP RO strings.
NetBrain Tip: All device credentials are stored in the NetBrain Mongo database with the passwords encrypted.
Live Network Discovery
NetBrain uses a custom neighbor-walking algorithm to (optionally) discover your network. Using one Telnet/SSH session per device, NetBrain will generate light network traffic during a NetBrain discovery. For the quickest and most comprehensive discovery, ensure that the NetBrain Front Server(s) will access the devices on the network with the following methods:
- Ping
- SNMP Read-only
- Telnet/SSH
During the Discovery operation, the NetBrain Discovery Engine will take the following actions against the devices, in the following order.
- Ping
- SNMP RO GET to a list of known OIDs
- Telnet to port 23 or SSH to port 22, and execute device appropriate CLI commands to gather configuration information
show run
show ip route summary
show ip route
show cdp neighbor
NetBrain Tip: NetBrain supports a large number of devices in the platform, however, there will always be devices that exist in a customer network where NetBrain lacks proper support. If these devices exist in your network, please contact NetBrain Technical Support at support@netbraintech.com
System Benchmark
During a System Benchmark task, the NetBrain Front Server accesses network devices using Telnet/SSH and issues CLI commands to retrieve configuration files, route tables, ARP tables, CDP tables, MAC tables and interface information.
For example, with Cisco IOS devices, the benchmark process may issue the following show commands:
- show run / show config
- show cdp neighbor detail
- show interface
- show arp
- show mac-address-table dynamic
- show ip route
Benchmark data is used to build or update the NetBrain Layer-3 and Layer-2 topology so that the system is always up-to-date. Benchmark data is a snapshot of your network at a specific time point so it can also be used for comparison purposes during troubleshooting.
For example, following an implemented network change, NetBrain recommends that the NetBrain Administrator executes a benchmark before and after the change window and perform comparison of the two sets of data. This will empower the NetBrain users to identify issues caused by the changes, such as missing routes.
Path Calculation
With two known IP Addresses/Hostnames, a NetBrain User can perform a path calculation. The NetBrain platform will retrieve route information via SNMP or CLI from your live network during a device discovery and/or System Benchmark task. This routing information will be used in performing the path calculation.
The accuracy of the NetBrain path calculation will be entirely dependent on the quality of the information retrieved from the network devices.
- Device Discovery (SNMP): NetBrain will only retrieve routes related to the destination rather than the entire route table.
- Device Discovery (CLI): NetBrain retrieves route tables from the device via show commands such as show ip route.
NetBrain provides an array of options for path calculation. Consult the NetBrain user documentation for more details, or contact NetBrain Technical Support at support@netbraintech.com if path calculations are not working correctly in your system.
Execute CLI Commands
If show commands can be issued in a non-privileged mode, then the system does not enter the privileged mode. Otherwise, the system has to enter the privileged mode to issue show commands. The NetBrain platform device drivers are designed to not make any configuration changes.