User guide

HP Virtual Connect for Cisco Network Administrators (version 4.x)
Document Number: C01386629 Date: January 2014
page 27
VC Uplinks and VLAN Trunking
Virtual Connect supports VLAN tagging (trunking) on VC uplinks using IEEE 802.1Q and can be
configured to support VLAN tagging on blade server NIC ports.
VC Uplinks can operate in one of three modes:
 VLAN trunking mode
 Shared Uplink Set (SUS) plus tagging on external switch port
 When a VC uplink is a member of a SUS and is connected to a VLAN trunk port on an
external switch, it operates as a VLAN trunk port.
 Multiple vNets, multiple VLANs
 No tagging on server NIC ports
 Example: VC Uplink 3 in figure below
 VLAN tunneling mode
 Single vNet plus tagging on external switch port
 When a VC uplink is a member of a single vNet and is connected to a VLAN trunk
port on an external switch, it operates in a mode that is equivalent to ‘dot1qtunnel’
mode on a Cisco switch.
 Single vNet, multiple VLANs
 Tagging on server NIC ports
 Example: VC Uplink 2 in figure below
 Access mode
 Single vNet plus no tagging on external switch port
 When a VC uplink is a member of a single vNet and is connected to an external
switch port in access mode, it operates in a mode that is equivalent to ‘access’
mode on a Cisco switch.
 Single vNet, single VLAN
 No tagging on server NIC Ports
 Example: VC Uplink 1 in figure below
When VC is configured to support VLAN tagging on a VC uplink (VLAN trunking mode), this means that
VC is interpreting (i.e. removing and inserting tags, classifying the frame’s vNet membership based on
tag info) the tag and is a termination point for the tag (i.e. the servers do not see the VLAN tag). This is
accomplished on VC by using “Shared Uplink Sets”, or SUS for short. A SUS is one or more VC uplinks
that are configured as VLAN trunks (tagging) and correlate external VLANs to specific vNets within
the VC Domain. The Administrator creates the SUS, adds one or more VC uplinks, defines which
VLAN tags are carried on the VC uplinks and then provides a vNet name (ASCII) for each of the
VLANs defined. This means that the uplink ports within the SUS provide external connectivity for
multiple vNets. In other words, one or more vNets share a set of uplinks for external network connectivity.
This is why the term “Shared Uplink Sets” is used. See VC Uplink 3 in the figure below.
When VC uplink ports are assigned to a single vNet and connected to an external switch port in VLAN
trunking mode, the VC uplink and vNet operate in VLAN\CoS tunneling mode or dot1qtunnel mode by