BGP Multi-Homing for Enterprises: A Practical Introduction
Using your own IP space across two providers gives maximum resilience. Here is how BGP multi-homing works.
Large enterprises, hosting providers and financial institutions often connect to two or more internet providers and announce their own IP addresses to all of them. This approach, called BGP multi-homing, offers the highest level of internet resilience.
The problem it solves
With a single provider, your public IP addresses belong to that provider. If their network has a major issue, your services become unreachable, and switching providers means changing every IP address — updating DNS, firewall rules and partner allowlists.
What you need
- An Autonomous System Number (ASN) that identifies your network on the internet.
- Provider-independent IP addresses allocated to your organisation.
- Routers capable of BGP and engineers who know how to configure them.
- Connections to two or more providers that support BGP sessions.
How it works
Your routers establish BGP sessions with each provider and announce your IP prefixes. The internet learns that your addresses are reachable through both providers. If one connection fails, routes through it are withdrawn and traffic flows through the other automatically — usually within seconds to a couple of minutes.
Traffic engineering
BGP also lets you influence which paths incoming and outgoing traffic take, for example preferring one provider for cost or performance reasons while keeping the other as backup.
Considerations
BGP is powerful but requires careful configuration to avoid route leaks or instability. Monitoring is essential. Many organisations rely on managed edge services to handle configuration, filtering and monitoring.
Is it right for you?
If public-facing services must remain reachable even when an entire provider has problems, and you need IP continuity, multi-homing is the gold standard.
The bottom line
BGP multi-homing provides provider independence and maximum resilience. UbiFi DIA supports BGP sessions and can work alongside your other providers.
Learn more about Dedicated Internet Access (DIA) from UbiFi, or talk to our team.
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