Specifications

HP Virtual Connect for Cisco Network Administrators (version 1.2x) page 12
external devices or to provide connectivity between two external networks. Virtual Connect is not,
and can not be configured as, a transit device. In other words, VC can only provide internal
connectivity between blade servers and\or VC can provide external connectivity to blade servers
but Virtual Connect cannot provide connectivity between two external devices.
The basic definition of a Virtual Connect Network, or vNet, is a logical grouping of VC ports
(downlinks or downlinks & uplinks) that comprise a single layer 2 network or broadcast domain. A
vNet is analogous to a vSwitch, as used by VMware technology (see “Comparing VC and VMware
Networking Technology” for an in-depth comparison). A vNet does not always represent a one-to-
one correlation with a VLAN, as can be seen in the next section entitled “Virtual Connect Ethernet
Connectivity Designs”.
Server NIC ports assigned to the same vNet can communicate directly (at layer 2) without having to
leave the enclosure. In the figure below, Server Blade 1 and Server Blade 2 can communicate with
each other within the VC Domain. Also, server NIC ports in different vNets are isolated (at layer 2) by
Virtual Connect from other server NIC ports. Server Blade 16 is isolated from Server Blades 1 thru 3.
Figure 3. VC Domain Showing Various Uses of vNets
(see Appendix A for a description of the elements in the above diagram)
Note:
Layer 2 connectivity is defined as any two devices that can communicate with each other by
directly exchanging Ethernet frames, carrying any protocol, without traversing a router or layer 3
switch. A layer 2 network could also be defined as a “broadcast domain”. For example, when a
frame is broadcast within a vNet, only ports assigned to the vNet will receive the broadcast frame
(unless an external device bridges multiple vNets together).
VC Uplink Fault Tolerance
Virtual Connect can be configured to provide both fault tolerance and load balancing for Virtual
Connect Networks and the associated server NIC ports. An Administrator can choose whether a
vNet operates in fault tolerance only mode by setting the vNet’s connection mode to “Failover” or