One option is to disable Spanning Tree on the 10G ports.  This is not a recommended practice.   Console(config)# interface te1/0/1 Console(config-if)# spanning-tree disable As long as you do not have a loop ( more than a single connection/path) when connecting the devices you should be OK. If your looking for more information on troubleshooting Spanning Tree check this out. en.community.dell.com/.../19465205.aspx
I'm having trouble configuring (2) 5524 switches.  Here's a simplication of the problem I'm having: Gigabit Port 2 on both switches is an access port on VLAN 2.  Gigabit Port 3 on both switches is an access port on VLAN3.  All other Gigabit ports are VLAN1.  Both SFP+ slots have a 10G fiber transreceiver in them.  10G port 1 is configured as trunk, only a member of VLAN2.  10G port 2 is configured as trunk, only a member of VLAN3.  The intent is for data to ingress into Port 2 on one switch, travel over the 10G fiber port 1, then egress on Port 2 of the other switch.  Similarly, data will ingress into Port 3 of Switch 1, travel over the 10G fiber port 2, then egress on Port 3 of the other switch. When I have only 10G port 1 connected, it works as intended - data in Port 2 on one side, out Port 2 on the other (and only port 2).  When I have only 10G port 2 connected, it works as intended - data in Port 3 on one side, out on port 3 on the other (and only port 3). The problem occurs when I connect both fiber ports.  When I do this, data only travels on 10G port 1 (VLAN2 data that is).  It's almost as it 10G port 2 is disabled when 10G port 1 is active.  They work fine individually, but 10G port 2 goes silent when they're both active. The overall intent here is to split traffic between the switches over (2) 10G links for performance reasons.  I'm using the single port example because it is simple and the problem reproduces under that configuration. Thanks.
VLAN traffic between (2) 5524 switches