Switches are switches - essentially multi-way bridges.
Originally, Ethernet hubs used to be repeaters - as the signal came in on one port, it was repeated out the others. If two devices were trying to talk simultaneously, they would each back off and try again a short random time later. For the last 15 years or so, they’ve typically ben switches - they receive the entire packet on one port, determine from the “header” who the packet is for, and re-send it out the appropriate port(s).
Switches may or may not have the following features, which may or may not be relevant to a small home network:
MAC address table -all switches build lists of what network devices (MAC addresses) they see, and on what port. This allows them to direct traffic. This is basically what a switch does to switch.
Auto-negotiate - There are devices that use 10Mb, 100Mb, and 1Gp speed connections. Most newer switches will negotiate the fastest speed the device at the other end will allow, and “dumb down” for older devices. All switches do this nowadays. Older switches (15 years ago or more) required you to configure ports for MDI or MDI-X (hooked to a PC or to another switch?) to determine which wires in the cable were transmit and which were receive. Most switches in the last 10 years auto-detect this as well.
Spanning-tree - builds a list of devices attached to the network and their connections - so it can detect other switches, for example, and redundant links to other switches- spanning tree can cause the redundant link to sleep, and will revive it if the active link fails.
Manageable- Some switches can be assigned an IP address, can allow you to enable/disable the ports, monitor traffic, configure the networking, etc. Typically this is by telnet or web page.
VLANs - this feature allows multiple separate networks to be configured on one set of hardware. This allows managed switches flexibility in keeping networking separate (i.e. office internal and public access networks). Traffic on a port can either be tagged or untagged. tagging allows multiple VLANs to use one cable as a switch-to-switch trunk.
Some switches (especially CISCO) have a plethora of other features - security, where only certain devices (by MAC) are allowed on the port. Limit the number of devices on one port (so end user can’t connect their own switch). Block traffic based on criteria. There is even a new 10Gbps standard.
A lot of these features have been present on high end switches for a decade or more. they are slowly becoming available on more and more lower-priced switches. But, unless you are a techno-gasmic geek and love to fiddle with things, all you need is a basic, unmanaged, 1Gb switch.
