NX-OS CDP Helpers

Overview

Python scripts designed to assist network engineers working with NX-OS devices. The primary focus is on enhancing the visibility and manageability of Cisco Discovery Protocol (CDP) information while working with NX-OS CLI; i.e., via console or ssh.

Set up

With Guestshell (N9K)

1. Init guestshell, adjust resize commands to your preference.

   # Disable guestshell to resize allocations
   guestshell disable
   y
   
   # Resize guestshell allocations
   guestshell resize cpu 10
   guestshell resize mem 2048
   guestshell resize rootfs 2000
   guestshell enable

NOTE: Steps 2-5 are to be ran straight from NX-OS CLI. To run within guestshell, enter guestshell in NX-OS CLI and then run the commands without "guestshell run".

2. Set up DNS for guestshell and test DNS ping.

   guestshell run sudo sh -c 'echo nameserver 9.9.9.9 > /etc/resolv.conf'
   guestshell run sudo chvrf management ping -c4 google.com
   

3. Update guestshell & add dependencies, the yum update process may take a while.

   guestshell run sudo chvrf management yum -y update
   guestshell run sudo chvrf management yum -y install git
   guestshell run sudo chvrf management pip3 install natsort

4. Clone repository.

   guestshell run sudo chvrf management git clone https://github.com/derek-shnosh/nxos-cdp-helpers.git /bootflash/scripts/nxos-cdp-helpers/

5. Remove guestshell DNS config (security measure).

   guestshell run sudo sh -c 'echo "" > /etc/resolv.conf'

6. Create CLI aliases to run the scripts.

   cli alias name cdpbr guestshell run python /bootflash/scripts/nxos-cdp-helpers/python/nxos-cdp-brief.py
   cli alias name cdpdesc guestshell run python /bootflash/scripts/nxos-cdp-helpers/python/nxos-cdp-describe.py -i

Without Guestshell

1. Copy the scripts to the switch.

   copy <source>/nxos-cdp-brief.py bootflash:scripts/
   copy <source>/nxos-cdp-describe.py bootflash:scripts/

2. Create CLI aliases to run the scripts.

   cli alias name cdpbr python /bootflash/scripts/nxos-cdp-brief.py
   cli alias name cdpdesc python /bootflash/scripts/nxos-cdp-describe.py -i

Script: nxos-cdp-brief.py

This script generates a custom CDP neighbor brief table that displays the local interface for each neighbor, along with the neighbor hostname, connecting interface, IP address (mgmt preferred), and optionally their platform and software version.

Features

• Multiple Neighbors Handling: The script accounts for interfaces with multiple CDP neighbors. This is particularly useful in situations where a downstream switch may pass CDP information from subsequent switches, or for Hypervisor vSwitches passing CDP information for guest VMs.
• Natural Sorting: Uses the natsort module to sort neighbors by interface in a human-readable order. If natsort is not installed, a lexicographical sort is performed (see the natsort PyPI page for elaboration).
• Optional Information: Display additional platform and version information using -p and -v arguments.

Output Fields

• L-Intf: Local interface where the neighbor was discovered.
• Neighbor: Neighbor's hostname.
• N-Intf: Neighbor's interface connected to the local interface.
• Mgmt-IPv4-Addr: Management IPv4 address of the neighbor.
• IPv4-Addr: Neighbor's highest valued IP address, only shown if different from the management IP.
• Platform (-p): Neighbor's platform or model (optional).
• Version (-v): Neighbor's software/firmware version (optional).

Example Usage

# CDP brief output
cdpbr

Script: nxos-cdp-describe.py

This script will rename interfaces based on the CDP information present, formatted as HOSTNAME:INTF. For example, if NX-OS interface Eth1/3 has a neighbor entry for IDF-1-ACCESS that is uplinkd using its Te1/1/1 interface, the description would be IDF-1-ACCESS:1/1/1

Features

• Single interface description: Run the script against a single interface to rename only that interface, no prompt provided.
• Interface descriptions for all interfaces with CDP neighbors: Run the script against all interfaces and it will parse neighbors and prompt to update descriptions accordingly.

Example Usage

# CDP describe, single interface
cpdesc Eth1/3

# CDP describe, all interfaces
cdpdesc all

Requirements

• Python 2.x/3.x
• NX-OS device with the capability to run Python scripts

License

This project is licensed under the MIT License - see the LICENSE file for details.