TS-7840 switch

The Marvell 88E6352 switch is supported by Linux's DSA (Distributed Switch Architecture). On startup Linux will expose all of the external ports as separate Ethernet ports. List all interfaces with:

ip a

The "lan0-lan4" ports on the TS-7840 are the external switch ports. By default these are configured to forward packets between the external port, and the CPU "eth2" interface. Packets will not forward between the external ports unless configured with brctl. To bring up a lan port:

# Bring up eth2, required for any of the switch
# ports to send/receive packets to the CPU
ip link set eth2 up
ip link set lan0 up
# At this point lan0 can be configured like any normal network interface
# Eg, start a dhcp client:
dhclient lan0

The switch can also be configured to connect ports together to pass packets without the CPU's intervention. This is done with brctl. For example, to bridge lan0 and lan1 together:

# Create a bridge interface
brctl addbr br0
# Add interfaces to the bridge
brctl addif br0 lan0
brctl addif br0 lan1

# Bring up the interfaces, note that eth2 is not
# required to be up in order to bridge the ports 
# unless packets must be accessed by Linux.
ip link set lan0 up
ip link set lan1 up
# lastly, bring up the bridge
ip link set br0 up

After this bridge is up, to access lan0/lan1 ports the br0 interface should be used. This br0 interface can now be treated like any other interface. Additional bridges can be created with "brctl addbr", and may include any of the externally available network ports.