http://wiki.mikrotik.com/wiki/Manual:Interface/Bonding

Also called link aggregation

/interface bonding add comment="Bonded interface between X router and Y switch" \
  mode=802.3ad name=name-of-bond slaves= ether11,ether12

http://blog.bravi.org/?p=343

Cisco calls bonded interfaces EtherChannel

/interface bonding add slaves=ether11,ether12 mode=802.3ad lacp-rate=30secs link-monitoring=mii \
  name=rtr-01_sw-1g-01_bond

!
interface range gigabitEthernet 1/47-48
   channel-protocol lacp
   channel-group 1 mode active
!
interface port-channel 1
   description rtr-01_sw-1g-01_bond
   switchport
   switchport mode access
   swichport access vlan XX
!

show lacp internal