Network Code

Miscellaneous code primarily used in my role as a network engineer.

Python Scripts

nxos-cdp-brief.py

nxos-cdp-brief.py is a script to run on an NX-OS device to print a custom CDP neighbor brief table.

I wanted a way to print a CDP brief while working on NXOS switches, to include each neighbor's Local interface along with the Neighbor hostname, interface, IP address (mgmt preferred), and optionally their platform and/or version.

The script will account for interfaces with multiple neighbors; this is useful when a downstream switch might transparently pass CDP information from subsequent switches, or when ESXi vSwitches are passing CDP info for guest VMs.

The script will attempt to import and use the natsort module to naturally sort the neighbors by interface, in ascending order. If natsort is not available, the results will still be sorted lexicographically (see the natsort PyPI page for elaboration).

One line is printed per CDP neighbor, containing the following information (reference the screenshot below);

*(Optionally), use the args -p or -v to print the CDP table with platform or version information, respectively. There may be some regex parsing issues, has only been validated against most Cisco equipment and some ESXi builds.

Abbreviation	Definition
L-Intf	Local interface, where the neighbor was discovered.
Neighbor	The neighbor's hostname.
N-Intf	The neighbor's interface that connects to ours.
Mgmt-IPv4-Addr	The neighbor's Mgmt IPv4 address.
IPv4-Addr	The neighbor's highest valued IP address, only shown if this differs from the Mgmt-IPv4-Addr.
(Platform) -p	The neighbor's platform, or model, information.
(Version) -v	The neighbor's software/firmware version.

Usage

1. Enable guestshell on the NX-OS device (optional).
2. Install the natsort python module via guestshell (optional);
   • sudo chvrf management pip install natsort
3. Copy this script to bootflash:/scripts/nxos-cdp-brief.py
4. Create a command alias on NX-OS CLI;
   • With guestshell: cli alias name cdpbr guestshell run python /bootflash/scripts/nxos-cdp-brief.py
   • Without guestshell: cli alias name cdpbr python /bootflash/scripts/nxos-cdp-brief.py
5. Type cdpbr in NX-OS CLI to output a useful CDP brief table.