Site-to-Site VPN vs. Direct Connect: Which Is Better?

#arclogiq

Neither one is "better" in any universal sense, and the fact that this question gets asked so often as though it has a single right answer is exactly why so many businesses end up with the wrong option for their actual situation. This comes down to a genuinely simple tradeoff once you strip away the vendor marketing on both sides: cost and setup speed versus performance and consistency.

What VPN Actually Gives You

Site-to-site VPN rides over the regular public internet, encrypted, connecting your infrastructure to the cloud. It's fast to set up often working within hours and cheap, since you're not paying for dedicated physical infrastructure. The tradeoff is genuine and worth being honest about: performance is subject to whatever's happening on the public internet at any given moment, which means latency and throughput can vary in ways you don't control and can't always predict.

What Direct Connect Actually Gives You

A dedicated connection AWS Direct Connect, Azure ExpressRoute, Google Cloud Interconnect is a genuinely private, physical link between your infrastructure and the cloud provider's network, bypassing the public internet entirely. Performance is considerably more predictable, latency is generally lower, and for high-volume, sustained traffic, it's often genuinely cheaper per gigabyte than the equivalent VPN traffic once you're moving enough data regularly. The cost is real setup time often weeks, sometimes longer depending on your location and meaningfully higher fixed cost, especially at lower volumes.

The Question That Actually Decides This

Ask honestly: how much does performance consistency actually matter for what's crossing this connection, and how much data volume are we actually talking about? A connection carrying occasional file transfers and non-critical traffic genuinely doesn't need the cost and lead time of a dedicated connection. A connection carrying your primary application's database traffic, or supporting real-time, latency-sensitive operations, genuinely benefits from the consistency a dedicated connection provides inconsistent latency on that kind of traffic shows up directly as a worse experience for whoever's depending on it.

Don't Treat This as All-or-Nothing

A genuinely reasonable pattern a lot of businesses land on: dedicated connection for the traffic that actually needs the consistency, VPN for everything else, and this part gets missed constantly VPN as a legitimate failover path if the dedicated connection ever goes down, since dedicated connections aren't themselves immune to outages despite their reliability advantages.

The Setup Timeline Trap

This is worth flagging directly because it burns businesses regularly: Direct Connect and its equivalents take real time to provision, and that timeline needs to be planned around well in advance, not discovered the week before a project needs the connection live. Businesses that wait until they're certain they need a dedicated connection, then try to set it up on a tight deadline, frequently end up stuck on VPN longer than they wanted simply because nobody started the provisioning process early enough.

What Actually Determines the Right Choice

How much performance consistency genuinely matters for the specific traffic crossing the connection

Actual sustained data volume, since dedicated connections often become cheaper per gigabyte past a certain threshold

Realistic setup lead time, planned for well ahead of when the connection actually needs to be live

Whether a hybrid approach genuinely fits dedicated for critical traffic, VPN for everything else and as failover

The Actual Point

This was never really a competition between a better option and a worse one. It's a genuine tradeoff between speed-and-cost on one side and performance-and-consistency on the other, and the right answer is whichever side of that tradeoff actually matches what's crossing your specific connection not whichever technology sounds more impressive in a vendor's pitch deck.