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ISP Redundancy

ISP redundancy protects network connectivity by maintaining multiple internet connections from different providers, ensuring access to the outside world if a primary connection or provider fails.

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About this video

A network can have robust internal redundancy and still face a critical vulnerability if its internet connectivity depends on a single provider. If that ISP experiences an outage or service disruption, the entire organization loses access to the outside world regardless of how well the internal infrastructure is designed. Addressing this requires maintaining connections to multiple internet service providers, not just multiple circuits from the same one. Having two circuits from the same ISP protects against physical link failures but offers no protection when the provider itself has a problem. Distributing connectivity across different ISPs closes that gap. The secondary connection is typically provisioned at a lower bandwidth than the primary, since it is intended only to carry critical services during a failover event rather than support full organizational traffic. This secondary link is often implemented using an alternative access technology, such as a cellular or wireless connection, which further reduces the risk of a shared infrastructure failure affecting both providers simultaneously.

What you'll learn

What's covered

ISP Redundancy

Key terms

Redundancy
The duplication of critical components or systems to increase reliability and availability.
Failover
The automatic switching to a redundant system or component when the primary one fails.
Single Point of Failure
SPOF
A component within a system whose failure would cause the entire system or service to become unavailable.
Internet Service Provider
ISP
A company that provides customers and organizations with access to the internet and related services.
ISP Redundancy
The use of multiple internet service providers to ensure continued connectivity if one provider experiences an outage.

Topics

Isp Redundancy Network Redundancy Multi Homing Failover Networking High Availability

Transcript

To piggyback on the concept of network redundancy, we're also going to have to have internet service provider redundancy.

Somewhere within our network, we probably have connectivity to the internet. But this is a single source of failure. So if this were to go down, or something were to happen with our internet service provider, how would we get to the outside world?

To compensate for this, we would have multiple internet connections. Now, sometimes I've seen those internet connections from the same ISP, the same internet service provider. What that does is it guards against these connections failing, but it doesn't guard against the internet service provider having an issue in itself. So we probably want to distribute this amongst different ISPs.

This second connection typically I see as being a little bit smaller. It's only a backup, it's only for critical services, it's not for everything. And so many times this might be like a wireless connection, like a cellular connection, or just from a different service provider that can provide those types of services.

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