I have two data center in our city and we hired the data transport service with two different carriers, the whole path is level II, so I have a problem because I'd like to use one link like act as a backup to the other "active- passive", or in the better way "active-active", but I cant find the tool to control this. For example STP is not very common in metro Ethernet carrier network, so the other option could be flex link, but it only changes to back up link if the interface goes down. I'm also taking a look at port aggregation, but I'm not sure if it can pass through the two carriers networks. Any Ideas ??