In IT, “one is none, and two is one.” Redundancy eliminates single points of failure (SPOF) to ensure business continuity.
ISP Redundancy
Never rely on a single Internet Service Provider (ISP). Have a primary fiber line and a secondary cable or 5G/LTE backup. Use an SD-WAN or Dual-WAN router to automatically failover if the primary line drops. Ensure the physical cables enter the building at different points if possible (“path diversity”).
Hardware Redundancy
Core switches should be stacked or paired using protocols like VRRP or HSRP so that if one dies, the other takes over the IP address instantly. Servers should have dual power supplies plugged into separate UPS units or PDU circuits.
Power Redundancy
A UPS gives you minutes to save work; a generator gives you days to keep working. Ensure your UPS batteries are tested annually. Verify that your generator has a fuel contract for refills during extended outages.
Spanning Tree Protocol (STP)
When creating redundant cable paths between switches, you create loops. Without STP, these loops cause broadcast storms that crash the network. Ensure RSTP (Rapid Spanning Tree) is configured correctly on all switches to manage these redundant links efficiently.
Frequently Asked Questions
What is High Availability (HA)?
HA is a system design approach that ensures a prearranged level of operational performance, usually uptime, during a specific period. It minimizes downtime through redundancy.
Does Redundancy Double the Cost?
Often, yes. Buying two firewalls is twice the price. However, compare that to the cost of your business being offline for two days waiting for a replacement part. The ROI is usually clear.