VMware and HP have both released advisories which say you shouldn’t use HP Virtual Connect in tunnel mode if you are using vCloud Director Network Isolation (vCDNI) which is MAC-in-MAC encapsulation.
There are two network modes available with Virtual Connect, Tunnel Mode and Mapped Mode.
When using Tunnel Mode, Virtual Connect passes all tagged and untagged packets through the Virtual Connect switch down to select blades where the VLANs are split into port groups. The uplinks are therefore considered dedicated uplinks as control over which VLANs are trunked is done at the upstream switch and so you can’t have a different set of VLANs going to Blade 1 and Blade 2 while still utilising the same uplinks. You could obviously have separate sets of uplinks for Blade 1 and Blade 2 to achieve this. The advantage of tunneling mode is only having to specify your VLANs once at the upstream switch and being able to pass all VLANs down the same trunk to multiple blades and only having to manage VLANs at the upstream switch and port groups on the ESXi host or within the vSphere Distributed Switch.
In Mapped Mode mode, the Virtual Connect switch examines all the VLANs and by defining Ethernet Networks for each VLAN on the Virtual Connect switch you can selectively pass down all or some of the VLANs down to the blades. The uplinks are considered shared as you can trunk all VLANs you will need for any blade and for example have some VLANs going to Blade 1 and other VLANs going to Blade 2 but sharing the same uplinks. In order to do this you have to create separate Ethernet Networks for every VLAN (possibly two for redundancy) and manage VLANs at both the upstream and Virtual Connect switches as well as port groups on the ESXi host or within the vSphere Distributed Switch.