Introduction on the Key Points

We will walk through how to parse the show ip interface brief output across Cisco, Arista, Palo Alto, and FortiGate using pyATS & Genie parsers. This ensures uniformity in data interpretation, enabling us to audit reachability, interface statuses, and detect inconsistencies across platforms—all vendor-agnostically.

This hands-on blog is meant for network engineers getting into automation and building multi-vendor consistency. We’re using Python for Network Engineer automation, leveraging the power of pyATS and Genie to parse raw CLI outputs into structured JSON. No guesswork—just clean, actionable data.

By the end of this post, you’ll be confident in:

• Parsing show ip interface brief outputs across vendors
• Extracting interface status/description info in JSON
• Running a ping reachability validation
• Aligning multiple vendors in a single script
• Using pyATS testbed for consistent connectivity

---

Topology Overview

We are working with the following multi-vendor topology in our EVE-NG/PNET/physical lab:

This topology lets us simulate real-world distributed environments where devices from multiple vendors need to be validated together.

---

Why Vendor‑Agnostic Testing Matters

In a hybrid world with Cisco in DC, Arista at the Edge, Palo Alto in Security, and FortiGate for segmentation, standardizing validation becomes essential.

Vendor-specific commands may differ in structure, syntax, and response formats.

But vendor-agnostic validation with pyATS:

• Reduces CLI inconsistencies
• Enables unified automation pipelines
• Eliminates parsing headaches
• Ensures operational consistency
• Helps in change impact analysis and audits

This makes it an essential skill when working in regulated environments or automation pipelines.

---

Topology & Communications

• Protocols: SSH for all devices (fallback to Telnet for FortiGate if needed)
• Ping Tests: From pyATS host to each loopback interface
• Command used: show ip interface brief or its equivalent per vendor

---

Workflow Script

from genie.testbed import load
from rich import print
import json

# Load testbed
testbed = load('testbed.yml')

# Parse show ip interface brief
for device_name in testbed.devices:
    device = testbed.devices[device_name]
    device.connect(init_exec_commands=[], init_config_commands=[], log_stdout=False)

    print(f"\n[green]Connected to {device_name}[/green]")
    
    try:
        output = device.parse('show ip interface brief')
        print(json.dumps(output, indent=2))
    except Exception as e:
        print(f"[red]Parsing failed for {device_name}: {e}[/red]")

    device.disconnect()

---

Explanation by Line

Line	Explanation
from genie.testbed import load	Loads the pyATS testbed
testbed = load('testbed.yml')	Reads device connection details
device.connect(...)	Establishes connection to the device
device.parse(...)	Executes and parses the show ip interface brief
json.dumps(output, indent=2)	Beautifies JSON output for easy reading
device.disconnect()	Cleanly closes SSH/Telnet session

---

testbed.yml Example

devices:
  cisco-ios:
    os: iosxe
    type: router
    connections:
      cli:
        protocol: ssh
        ip: 192.168.100.1
        port: 22

  arista-eos:
    os: eos
    type: switch
    connections:
      cli:
        protocol: ssh
        ip: 192.168.100.2
        port: 22

  paloalto-fw:
    os: panos
    type: firewall
    connections:
      cli:
        protocol: ssh
        ip: 192.168.100.3
        port: 22

  fortigate-fw:
    os: fortinet
    type: firewall
    connections:
      cli:
        protocol: ssh
        ip: 192.168.100.4
        port: 22

---

Multi-Vendor CLI Screenshots

Cisco IOS-XE

Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0     10.1.1.1        YES manual up                    up
Loopback0              192.168.0.1     YES manual up                    up

Arista EOS

Port      IP Address       Interface Status
Et1       10.1.1.2         up
Lo0       192.168.0.2      up

Palo Alto PAN-OS

> show interface management
Name: management
IP address: 192.168.0.3
Status: up

FortiGate

FGT # show system interface
config system interface
    edit "mgmt"
        set ip 192.168.0.4 255.255.255.0
        set status up
    next
end

---

FAQs

Q1. What is the benefit of parsing show ip interface brief across vendors?

A: It helps in creating standardized reports, detecting interface issues proactively, and aligning network health status in multi-vendor environments without needing separate logic per vendor.

---

Q2. Can pyATS parse commands for non-Cisco platforms like Fortinet or Palo Alto?

A: Yes, with structured CLI output and proper testbed setup, pyATS with Genie plugins can parse data from most major vendors. Some may need custom parsers or unstructured text parsing.

---

Q3. What if a vendor doesn’t have a native parser in pyATS?

A: You can fall back on unstructured parsing (regex or templates) or write your own parser using pyATS’ extensible APIs.

---

Q4. Is the show ip interface brief command same across all vendors?

A: No. It varies slightly or significantly. That’s why vendor-agnostic parsing normalizes this data into a common JSON structure, removing human error from manual interpretation.

---

Q5. Can I use this script in CI/CD pipelines?

A: Absolutely. With proper testbed integration and result handling, this script can become part of a daily health check or validation before/after changes.

---

Q6. Do I need pyATS Genie parser libraries for each vendor?

A: Yes. Some vendors require specific parser support. Ensure your environment has the correct libraries installed or be ready to handle some parsing manually.

---

Q7. What if SSH is not working?

A: Fallback to Telnet if allowed. Also ensure:

• Proper username/password in .pyats.conf
• Devices are reachable (ping first)
• Firewall or ACLs are not blocking SSH

---

YouTube Link

Watch the Complete Python for Network Engineer: Parsing show ip interface brief across vendors using pyATS (Vendor-Agnostic) — Cisco/Arista/Palo Alto/Fortigate Lab Demo & Explanation on our channel:

---

Join Our Training

Are you ready to take your Python for Network Engineer skills to the next level?

I, Trainer Sagar Dhawan, have mentored 25,000+ engineers globally, and now invite you to join my 3-Month Instructor-Led Training Program focused on:

• Python Automation (Beginner to Advanced)
• Ansible Playbooks for Network Devices
• APIs for Cisco, Arista, Fortinet, Palo Alto
• Real-World Labs (EVE-NG) + Multi-Vendor Projects
• CI/CD Pipeline Concepts + pyATS + Nornir

Click below to view course outline and enroll:

Enroll Now & Future‑Proof Your Career
Email: info@networkjourney.com
WhatsApp / Call: +91 97395 21088

https://course.networkjourney.com/python-ansible-api-cisco-devnet-for-network-engineers

Transform your career with Vendor-Agnostic Automation Mastery and let’s automate networks together—one script at a time.

---