BGP Routing Protocol
Notice: This blog post was originally published on Indeni before its acquisition by BlueCat.
The content reflects the expertise and perspectives of the Indeni team at the time of writing. While some references may be outdated, the insights remain valuable. For the latest updates and solutions, explore the rest of our blog
So what is BGP? In this series of posts I will be explaining the main principles of BGP. BGP–Border Gateway Protocol–is the de facto core routing protocol of the Internet. It operates by exchanging routes among Internet Autonomous Systems, and it is considered a path vector protocol. Routing is performed by shortest path possible and according to network policies within each Autonomous System. Most large service providers use BGP, and enterprises can operate BGP internally to influence metrics.
BGP operates in Layer 4 of the OSI network model and establishes TCP connections via port 179 between neighbors. BGP that is used internally is designated as iBGP and when used externally it is designated as eBGP. The implementation of routing policies are done mainly by route maps. For example, influencing traffic with BGP policies can be done with the MED (Multi-Exit Discriminator) attribute, which tells a remote AS that a specific entry into an AS is the preferred one. Therefore, BGP is great for multi-homing to different ISPs (in terms of load balancing and backup).
ISPs that run BGP also integrate Multiprotocol BGP (MP-BGP). It is a special extension of BGP that works with MPLS, which allows service providers to offer businesses VPN capabilities and secure connectivity across multiple branches.
This technology is very widespread in large-scale enterprises. Proactive monitoring and fault resolution of BGP is essential due to its importance and influence on the topology.
Smart BGP signatures are already embedded into indeni and many others are planned.
Here are several examples for checks indeni has around BGP configuration:
- BGP Neighbor Is Down – indeni will alert when neighbors appear to be down in neighbors tables.
- BGP Neighbor State Has Changed – indeni will alert when the state has changed for any BGP peers or neighbors in the peer/neighbor table.
- Some Network Summarizations Are Too Loose – indeni will verify that network summarizations are not too loose, and that they do not contain unreachable networks.
- Internal Devices Given an External IP – indeni will alert if a public IP address has been used in an internal network.
Related content
Route traffic intelligently with DNS-based GSLB for BlueCat Edge
Discover how DNS-based GSLB with BlueCat Edge empowers networking teams to control traffic steering, reduce costs, and improve resilience.
Webinar Making APIs Work for You (Part 5)
Welcome to Part 5 of Making APIs Work for You. Our community specialist, Vivek Mistry, is your guide, and today, Vivek will focus on user security…
Exciting product update: Introducing BlueCat Integrity X
Introducing BlueCat Integrity X, a single platform for complete visibility and control over critical network services.
Article What is protective DNS (PDNS) and why is PDNS important?
Discover what protective DNS is, how it prevents cyber threats like phishing and malware, and why it’s essential for modern enterprise network security.