I have a couple Sup6-E each with 2 10gb ports. I wanted to bundle each pair on each sup in an etherchannel that uplinks to 2 different Distribution Layer swithes, 3750-Es. I've entered the shared backplane command, and reloaded the sups and have green on all 4 of my sup 10gb ports, but only the 1st interface on each sup is lighting up the other end of the links on the 3750s. The documentation I've come accross seems to indicate that you can have all 4 sup ports active, but I did see something about certain models of the 4510 series only being able to use one of the links when using sso or rpr for redundancy modes, though the 4510R-E wasn't among them. Is this a limitation of the redundancy config, or is there something I'm missing to enable it? I've double check the transmit and receive keys, it doesn't seem to be a physical issue. I've swapped the known good link into one of the 2nd interfaces that isn't lighting up, and still no lights.