What is an upstream SFP port?

Upstream ports are opposite transmit and receive ports, and are designed  for internal switch connections, using standard straight-through cables instead  of crossover cables. Therefore, the upstream port can be connected to the  regular port of another device. Plugging the upstream port of one switch into  the standard port of another switch helps to scale the network. Most enterprise  switches on the market contain 24 RJ45 ports and 2 dedicated SFP ports for  uplinks or 48 copper ports and 2 or 4 dedicated SFP uplink ports. Each uplink  SFP port has two LEDs that indicate the port's activity and status. FS.COM also  offers these uplink SFP ports on 8-port and 24-port Gigabit PoE switches to  achieve 1 gigabit per second data rates.