Hub vs Switch: What’s the Difference?

A hub repeats everything it receives out of every other port. A switch learns which device is on which port and sends traffic only where it’s addressed. That one difference is why hubs are slow and noisy, and why every wired business network today is built on switches.

If you’re buying: buy a switch. You can’t really buy a new hub anymore, and most small boxes still sold as a “hub” are unmanaged switches.

Hub vs switch at a glance

	Hub	Switch
How it forwards traffic	Repeats every signal out of all other ports	Sends each frame only to the port where the destination is
Knows where devices are	No	Yes, it learns MAC addresses into a table
OSI layer	Layer 1 (physical)	Layer 2 (data link); Layer 3 switches also route
Bandwidth	Shared by every device on the hub	Full speed on each port
Duplex	Half duplex: send or receive, not both	Full duplex: send and receive at the same time
Collisions	Common; every port shares one collision domain	None on full-duplex links
Speeds	10 or 100 Mbps	1 Gbps to the desk is standard; 10 Gbps and up between switches
VLANs, PoE, management	None	On managed and PoE models

What is a hub?

A hub is a multiport repeater. A signal that comes in on one port goes out of all the others. The hub doesn’t read addresses and doesn’t know which device is where, so every device sees every other device’s traffic and ignores what isn’t meant for it.

Because the hub is one shared medium, only one device can transmit at a time. When two transmit at once, the signals collide and both retry. The more devices and traffic you add, the more time is lost to collisions. And the bandwidth is shared: ten computers on a 100 Mbps hub split 100 Mbps between them.

What is a switch?

A switch reads the source MAC address of every frame that comes in and remembers which port it came from. When a frame arrives for a device it has already seen, the switch sends it out of that one port only. Many pairs of devices can talk at full speed at the same time, and each port runs full duplex, so a 1 Gbps port sends and receives 1 Gbps at once.

A switch still sends some traffic everywhere: broadcasts (such as a device asking for an IP address) and frames for addresses it hasn’t learned yet go to every port in the same VLAN. Once devices start talking, the table fills in and almost all traffic goes point to point.

Hub vs switch vs router

A router is the third box people mix up. Hubs and switches connect devices on the same local network. A router connects different networks, most commonly your office network to the internet, and uses IP addresses to decide where each packet goes. A typical office: internet line, then a router or firewall, then switches, then computers, phones, printers and wireless access points.

Layer 3 switches blur the line: they route between VLANs inside your network at switching speed. You still put a router or firewall at the internet edge.

Is a switch more secure than a hub?

Yes. On a hub, any connected device can capture everyone else’s traffic just by listening. On a switch, a device normally sees only traffic addressed to it, plus broadcasts. Managed switches add real controls: VLANs to separate guest, voice and camera traffic, 802.1X to make devices authenticate before they get on the network, and port security to limit what can plug in.

A switch isn’t a security system on its own. Change default passwords, keep firmware current, shut unused ports and keep the management interface off the user network. More in how to secure a Cisco switch.

Is there any reason to use a hub today?

Rarely. The one real use was packet capture: plug a laptop running Wireshark into a hub and it sees everything. Managed switches do this properly with port mirroring (Cisco calls it SPAN), which copies traffic from the ports you choose to a monitoring port. If you find a hub in an old wiring closet, replace it.

Which kind of switch do you need?

• Unmanaged: plug in and go. No configuration, no VLANs, no monitoring. Fine for a desk or a small room, not for the core of a business network.
• Smart: VLANs, basic security and a web interface at a lower price. Example: the Cisco Business CBS250-48T-4X, 48 Gigabit ports with four 10G SFP+ uplinks.
• Managed: full control: VLANs, 802.1X, QoS for voice, port mirroring and monitoring. The Cisco Catalyst C9200L-24P-4G-E is a common access switch; Catalyst 9300 and other Cisco switches cover larger networks. The Meraki MS130-24P is managed from the cloud dashboard.
• PoE: powers phones, cameras and access points over the Ethernet cable. Add up the watts your devices need and check the switch’s PoE budget, not just the port count. More in how a PoE switch works.

Then size it: ports for today’s devices plus room to grow, uplink speed to match what’s upstream (1G or 10G), and enough PoE budget for everything you’ll power.

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Send us the part numbers you’re comparing, or the number of ports and PoE devices you need to connect, and we’ll quote it the same business day.