Setup and Install

Installation 28
• The following connections must reside within their configured logical interconnect for proper
functionality. These connections must not span outside of their logical interconnect:
o Network uplink ports
o Shared uplink sets
o Monitored ports
o sFlow ports
When configuring networks, uplink ports are filtered to ensure that all ports belong to the same logical
interconnect.
• If there are connections not configured as stacking links between modules, the ports are linked and
function as normal uplink ports.
• Server to server communications between logical interconnects requires a connection between the
logical interconnects.
• Multiple enclosure configurations are supported and require that the primary slices of the enclosures be
connected with stacking cables.
• Profile migrations are not supported in multi-enclosure domains.
• Double-dense mode is not supported.
• HP BladeSystem c3000 Enclosures are not supported.
• HP recommends enabling Smart Link.
To configure the domain stacking mode, see the latest versions of the following documents in the Virtual
Connect Information Library (http://www.hp.com/go/vc/manuals):
• HP Virtual Connect for c-Class BladeSystem User Guide
• HP Virtual Connect Manager Command Line Interface for c-Class BladeSystem User Guide
Network loop protection
To avoid network loops, Virtual Connect first verifies that only one active uplink exists per network from the
Virtual Connect domain to the external Ethernet switching environment. Second, Virtual Connect makes sure
that no network loops are created by the stacking links between Virtual Connect modules.
• One active link—A VC uplink set can include multiple uplink ports. To prevent a loop with broadcast
traffic coming in one uplink and going out another, only one uplink or uplink LAG is active at a time. The
uplink or LAG with the greatest bandwidth should be selected as the active uplink. If the active uplink
loses the link, then the next best uplink is made active.
• No loops through stacking links—If multiple VC-Enet modules are used, they are interconnected using
stacking links, which might appear as an opportunity for loops within the VC environment. For each
individual network in the Virtual Connect environment, VC blocks certain stacking links to ensure that
each network has a loop-free topology.
Enhanced network loop protection detects loops on downlink ports, which can be a Flex-10 logical port or
physical port. The feature applies to Flex-10 logical function if the Flex-10 port is operating under the control
of DCC protocol. If DCC is not available, the feature applies to a physical downlink port.
Enhanced network loop protection uses two methods to detect loops: