If this is Metro-Ethernet you can do Ether-Channel.Cisco on-board Eth ports do not support ether-channel however their NM modules and switches do.Check with your Service Provider if they support Ether-Channel.
HiDid the remote sites have ADSL with Static Public IP ?Will this work if the DSL provider only gives Dynamic IP ?Can the 1720 with dynamic IP initiate a tunnel to the HQ site?Thank You