SOHO stands for Small Offices and Home Offices, and usually refers to situations where there exists just one computer at home to a few computers in a small office.
There is a very large offer of SOHO routers on the market nowadays from various manufacturers, but from what I've tested, most of them do the same basic things (NAT, DHCP, and some port filtering). They are less expensive than any computer, but if you have an old computer that you are about to throw away, you can easily install Linux on it and make it your own SOHO router having the advantage of higher flexibility at zero cost.
Usually, a SOHO router has a WAN port that is an Ethernet port where the provider connection must be plugged in. The Provider's CPE (Customer Premises Equipment) can be of any type (xDSL modem, wireless bridge, cable modem, fiber optic media converter) that can provide an Ethernet connection. SOHO routers usually have four to eight Ethernet ports for the LAN. This is basically a small...