5720 Series switches can be stacked with themselves using Native V400 stacking (SummitStack-V400) . 5720 Series switches can also be stacked with 5520 Series switches using Native V200 stacking (SummitStack-V200). When creating a mixed stack of 5720 Series and 5520 Series switches, the Primary and Backup nodes must be 5720 Series switches and they must be configured for Native V200 stacking.