Circuit switching uses a dedicated path to move data between two endpoints, keeping the route reserved for the full session. This method is common in voice systems where steady delivery matters.

Some businesses still use circuit switching as part of a larger secure network design. Understanding how it works—and how it differs from other methods—can help you make better choices for performance, stability, and control.

What is circuit switching?

A circuit switch creates a dedicated path through the network before any data transfers.

Once two endpoints connect, that route stays exclusive to them until the session ends. Nothing else uses that lane. It doesn’t matter if the data pauses—no one else can borrow that space.

Legacy telephone networks are built on this model. Each call gets its own circuit, with guaranteed bandwidth for the entire conversation.

Operational phases

Circuit switching happens in three main steps: setting up the connection, transferring the data, and ending the session.

Each step controls how devices talk and how the network handles bandwidth during the connection.

Circuit establishment

The first step is setting up a dedicated path from sender to receiver. The network checks each switch along the way and reserves space just for that connection. Every switch stores the route information, making sure the same path is followed the entire time.

This path doesn’t change—even if faster or more efficient routes become available. The whole route must be ready and locked before any data can move.

In enterprise environments, this step is often handled by hardware like time-division multiplexers or circuit-switched PBX systems.

Data transfer

Once the path is built, data flows without interruption.

There’s no need to break data into packets or reassemble it later. Information moves in a steady stream—ideal for real-time traffic like voice or video. Because the network doesn’t reroute traffic mid-call, there’s no extra delay or jitter. The signal stays stable even if the rest of the network is busy.

In older telecom setups, this method helped keep long-distance calls clear. In modern networks, it's still used in private line services or internal voice systems that need guaranteed performance.

Circuit disconnection

When the session ends, the entire circuit is taken down. Each switch in the path releases the reserved space, returning bandwidth to the general pool. Other users and applications can now reuse the switches and links.

The disconnection process is just as controlled as the setup. That prevents confusion or data leaks if another user connects right after.

One downside is that no one else can use the path during gaps in the conversation. If there’s silence, bandwidth still stays locked—whether it's used or not.

Circuit switching diagram

Circuit switching creates a dedicated, locked-in path that data follows from start to finish. Every switch along the route is part of the full connection. Nothing else uses that path until the session ends.

Each device—called a switch—holds the route in memory while the connection is active. The sender and receiver only send data along that exact chain.

There’s no re-routing or shared usage. Even if another sender wants to use the same switches, they must wait until the circuit disconnects.

This structure is predictable. That’s what makes it useful in real-time voice systems or environments where timing matters.

Circuit switching vs. packet switching

Packet switching splits data into small chunks and sends each one on its own path. Circuit switching builds one continuous path and keeps it reserved from start to finish.

Packet-switched networks like the internet send data faster and more efficiently, but the delivery is less predictable. Circuit-switched networks keep data steady but tie up resources even when not in use.

This chart shows the differences in features between circuit switching and packet switching:

Some enterprise networks use both types. A common example is MPLS, which adds routing control to packet-switched traffic for better performance under load.

Advantages of circuit switching

Circuit switching still has real use in business networks—especially where timing and stability matter. It offers consistent performance by keeping every session on a fixed path.

Predictable performance with consistent latency

A locked-in route keeps delay and jitter under control.

Once the connection is active, no other traffic can interfere. That avoids spikes or slowdowns caused by network congestion. It also means no time lost to re-routing.

In call centers or financial trading floors, that level of predictability is hard to replace.

Suitable for real-time applications like voice calls

Real-time voice and video need steady, low-latency connections. Landline phone systems, office intercoms, and PBX setups often use circuit-switched links to avoid dropped packets or distorted sound. Even a short glitch can disrupt a conversation.

Some enterprises still run circuit switching for internal calls while using packet switching for everything else. It’s common in hybrid networks with legacy hardware.

Simple troubleshooting and monitoring

Circuit-switched paths are easier to trace and test.

Since the route is fixed, it’s easier for engineers to isolate issues. There’s no need to track how packets are being rerouted or reassembled across different nodes. Performance tools can monitor a single connection without chasing multiple paths. This simplicity can reduce mean time to resolution (MTTR) in environments where uptime is contractually important.

Strong quality of service (QoS) without complex configs

Guaranteed bandwidth doesn’t need advanced QoS settings.

In packet-switched networks, administrators often use QoS rules, traffic shaping, and prioritization to mimic what circuit switching does by default. In a circuit-switched system, the dedicated lane handles that automatically.

That can reduce complexity in setups where specific traffic types—like voice or control systems—need priority.

Disadvantages of circuit switching

Circuit switching can keep data steady, but it doesn’t handle modern network needs very well. It wastes space, costs more, and doesn’t scale when many users are active at once.

Wasted bandwidth during quiet times

If no one is talking, the network still holds the full connection. The line stays reserved, even if there’s no sound or data. That space can’t be shared. When traffic is light or bursts on and off, most of the bandwidth just sits there.

Packet switching avoids this. It only uses space when needed and frees it up right away.

Hard to scale with many users

Each new connection needs its own path through the network.

That works fine for a few calls. But with hundreds or thousands of users, the network runs out of space fast. Packet-switched networks let many users share paths and switch routes as needed.

More expensive to build and run

Circuit-switched gear is old and harder to manage.

You need special hardware to hold every call in memory. That means more equipment and more effort to keep it running. It also takes longer to train staff on both old and new systems.

Packet-based tools are cheaper to upgrade and easier to automate.

Not built for changing traffic

Circuit switching works best with steady traffic that doesn’t change much.

Modern apps don’t work that way. Data moves in short bursts, large spikes, or unpredictable flows. Circuit switching doesn’t adapt. If demand jumps, the network can’t shift resources to meet it.

Applications in enterprise networks

Circuit switching still shows up in business networks, especially when voice quality and timing matter. Some industries also keep it for legacy support or regulatory reasons.

Circuit-switched systems are common in:

• Landline and PBX phone systems
• Two-way radio networks
• Connections that need steady bandwidth
• Closed or air-gapped networks with strict controls

Many businesses also use network isolation to protect voice or command traffic. VLANs or separate links help keep audio streams from getting delayed by other traffic.

Real-time traffic that needs consistency

Some services can’t afford delays or jitter. Live audio, call centers, and private voice links need steady performance. Even a few dropped packets can cause noise or confusion. Circuit switching works well in these cases because the path never changes once it’s active.

Supporting legacy infrastructure

Some enterprise networks still run on a mix of old and new systems.

Legacy PBX setups, analog gear, or voice services tied to older contracts often need circuit-switched support. Tearing them out all at once is expensive. Many teams keep them running while slowly adding packet-switched systems around them, often as part of a larger enterprise network design strategy.

Moving toward packet switching

Shifting from circuit to packet networks takes planning.

Bandwidth guarantees don’t come built-in. You need tools like QoS settings, MPLS, or SD-WAN overlays to control traffic and keep latency low. Voice traffic must be shaped and protected, or quality will drop.

Security matters, too. Migrating voice or video traffic to shared IP links opens up new risks.

Implementing circuit switching in enterprises

Circuit switching can still be deployed in enterprise environments, but it comes with real tradeoffs. Setting it up means investing in older hardware, managing higher costs, and working around growth limits.

Enterprises that still use it often do so for specific reasons—like supporting legacy systems, meeting strict uptime requirements, or isolating voice traffic from the rest of the network.

Infrastructure requirements

Running a circuit-switched system needs dedicated hardware and careful planning.

The setup usually includes:

• Time-division multiplexers (TDM) to split and manage voice streams
• Circuit switches that hold active connections in memory
• PBX systems or gateways to connect old phones to modern networks
• Copper cabling or fiber that supports circuit switching standards
• T1 or PRI links for carrier handoff and external dialing

Every element is tuned for a single use case. Unlike modern network switches, they don’t adapt to changing traffic types. Keeping them running takes skilled staff who know how to trace sessions, configure switches manually, and diagnose timing issues.

Many of these systems are no longer widely produced, so replacement parts and vendor support can be limited.

Cost considerations

Circuit-switched systems usually cost more to build and maintain.

Each live call uses fixed hardware resources—no sharing. That means more power, more rack space, and more cooling per active connection. When usage is low, much of that equipment sits idle. When usage spikes, you either run out of ports or need to expand with more physical gear.

Maintenance adds to the total. Keeping older equipment online may require spare inventory, legacy support contracts, or on-call specialists.

Scalability and flexibility

Scaling circuit-switched networks is harder than scaling packet-switched ones.

Every new call needs its own end-to-end route. You can’t spin up sessions on demand or reroute around traffic. To grow, you often need new switch cards, port expansions, or entire racks. If you want to add call features—like three-way calling or voice recording—you may need extra servers or license keys, not just software updates.

Packet-based systems avoid this problem. Technologies like ethernet switching allow more devices to share bandwidth dynamically. You can add endpoints, spin up voice channels, or shift traffic between sites without touching the core hardware.

That flexibility is one reason many enterprises are moving toward hybrid or fully IP-based systems—especially when future growth is a factor.

Partner with Meter Connect

Some businesses still use circuit switching to support voice calls, legacy phones, or fixed connections. However, keeping those systems running can take a lot of time, gear, and staff.

Meter Connect makes that easier by getting you a better ISP.

We help support circuit-based systems where they still make sense. If your network relies on dedicated voice paths or steady connections, we help manage the setup and take care of the maintenance.

For companies looking to do more, we also offer a vertically integrated network. That means we handle the full service—not just the line. We take care of the equipment, the monitoring, and the updates. You don’t have to deal with outside vendors or bounce between providers.

Your team can focus on work. We handle the network.

Meter gives you a path forward—whether you’re keeping circuit switching for now or planning for something new.

Request a quote from us today on Meter Connect.