The Border Gateway Protocol (BGP) is the routing protocol that makes the internet work. Understanding BGP is essential for anyone managing IP addresses or operating network infrastructure.
What is BGP?
BGP (Border Gateway Protocol) is the routing protocol used to exchange routing information between autonomous systems (AS) on the internet. It's what makes global internet connectivity possible.
When you lease IP addresses and want to use them, you typically announce them via BGP to tell the internet "traffic for these IPs should come to my network."
How BGP Works
BGP works by exchanging routing information between peers.
Establish Peering
Your router connects to upstream providers or exchange points
Announce Prefixes
You advertise which IP ranges your network handles
Path Selection
BGP determines the best path for traffic based on various attributes
Key BGP Concepts
Understanding these terms is essential for BGP operations.
Autonomous System (AS)
A network under single administrative control, identified by an ASN
Prefix
An IP address range announced via BGP (e.g., 192.0.2.0/24)
Peering
The relationship between two networks exchanging routes
AS Path
The list of AS numbers traffic traverses to reach a destination
BGP Security
BGP was designed when internet security was less of a concern. Today, additional measures protect against route hijacking and leaks.
RPKI/ROA
Cryptographic validation that an AS is authorized to announce specific prefixes. Essential for preventing BGP hijacks.
BGP and IP Leasing
To use leased IP addresses, you need the ability to announce them via BGP. This typically requires an ASN and upstream connectivity.
IP Market provides the necessary LOA (Letter of Authorization) and helps configure ROA records for secure prefix announcement.