Learning BGP from Scratch: How to Practice with a Private ASN

BGP may look confusing. When I first tried to figure it out, I felt lost because I had no idea what I was doing. If you're in the same boat, don't worry about it. You don't need to be an ISP or have real Internet traffic to learn about BGP. You just need to practice! A simple setup can be created very quickly for practice purposes.

What BGP does​

It allows networks to determine which is the best route to send data. To me, that makes it similar to a map of Internet Traffic - it tells data where to go.

If you want to start practicing BGP, you should gather the following items:

• At least two routers
• Some IP addresses (subnets)
• A very basic lab setup

That's all there is to it!

How I Learned BGP​

When I was first learning to work with BGP, I used virtual machines to simulate a small network. By testing the different configurations I was able to better understand how everything worked and I could explore without worrying about breaking anything in a live environment!

To set up your practice environment, you can use any of the following products:

• BIRD or FRRouting
• Virtual routers
• Locally created labs or VPS servers

Making mistakes and fixing them will make it easier for you to learn faster than learning without having made any mistakes.

Private ASN - What Is It?​

The private ASN is used exclusively for practice purposes only. It is not used on the public internet and therefore, it provides a riskless way of learning BGP (Border Gateway Protocols).

Using a private ASN is beneficial for:

• Learning BGP Commands
• Testing Routing Rules
• Gaining Confidence

Why would you expose yourself to risks on the real world?

Do You Need To Use An ISP To Learn BGP?​

The answer is no. I learned how to use BGP only via the use of private ASN within a controlled laboratory environment. Once I had learned how to use BGP, the experience of working with real-world networks became so much easier.

Common Beginner Mistakes​

I made the following common beginner mistakes. Please learn from my past:

• I skipped the learning of basic networking knowledge
• I copied the configuration scripts from others without understanding them
• I had unrealistic expectations for a quick outcome

Learning BGP requires time.

Final Thoughts​

You do not need expensive network tools or special connections in order to learn BGP. Simply establish a small private ASN lab and practice regularly. With continued patience, you will attain the understanding of BGP - it feels great when you do!