We have a 881 router and it has 1 WAN port and 4 Fa ports. I want to know if it's possible to have 4 internet connections on that router to bond them .
the ISP's are on different subnets but the thing is that the router has only one WAN port and 4 LAN ports. My idea is to use the WAN port for the first ISP connect and 3 of the LAN ports for the 2,3,4 adsl connections then the 4 th fa port to go to the lan. Because I want to use LAN port I assume that I had to assign it to a different VLAN from the other 3 LAN ports. I don't know if that is even possible.
I believe that router only has the single wan port that you can use, and the other ports are strictly L2 ports. You can test this by going under one of the lan ports and try issuing a "no switchport" command to see if it takes. If so, you can put an address on the port. Another workaround possibly could be that you could create a vlan interface for every switchport and then add that switchport to the vlan that you created. Put your public address on the vlan interface and configure your connections.
The term bonding wouldn't be totally correct though because you're not using bandwidth across all of them. You'd be doing more round robin connections since these are to different ISPs. My gut feeling is to tell you that what you're wanting to do can't be done on this router, but I could be completely wrong.