The program swconfig allows you to configure configurable switches, like the

• RealTek RTL8366RB 5-port Gigabit switch, e.g. in the WR1043ND.
• RealTek RTL8366S, e.g. in the DIR-825
• Atheros AR8316, e.g. in the RouterStation Pro, WBMR-HP-G300H, …
• AR8216
• IC+ IP17xx
• Realtek RTL8306S
• please fill on all supported switches

• LEDs:

  swconfig dev rtl8366s port 0 set led 2

• Show current configuration

  swconfig dev rtl8366rb show
  

  and you will obtain:

  VLAN 1:
          info: VLAN 1: Ports: '12345t', members=003e, untag=001e, fid=0
          fid: 0
          ports: 1 2 3 4 5t
  VLAN 2:
          info: VLAN 2: Ports: '05t', members=0021, untag=0001, fid=0
          fid: 0
          ports: 0 5t
  

• Show available features

  swconfig dev eth0 help
  

• http://inst.eecs.berkeley.edu/~pathorn/ip175c/
• http://inst.eecs.berkeley.edu/~pathorn/ip175c/phylib-swconfig/
• http://www.debwrt.net/2010/11/07/switch-configuration-command-line-tool-swconfig-ported-2/
• http://www.icplus.com.tw/pp-IP175C.html
• OpenWrt Forum
• switch_port
• Is VLAN trunking on WR1034ND with VLAN id higher than 15 possible