i try to make 2 3548 stacked and then connect to 2 6509 for redundancy. I want to connect 3548A_uplink1 to 3548B_uplink2 with stack line(does this mean they are stacked?),then 3548A_uplink2------------6509A, 3548B_uplink1 --------------6509B using single mode fiber.BTW,could a 3549 and a 3524 be stacked? I am not sure about the correctness , any help is greatly appreciated. Frank _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]