Specifications

HP Virtual Connect for Cisco Network Administrators (version 1.2x) page 13
the Administrator can choose fault tolerance plus load balancing by setting the vNet’s connection
mode to “Auto”.
When an administrator assigns multiple VC uplinks to the same vNet, VC’s default behavior
(connection mode ‘auto’) for a vNet (or Shared Uplink Set) is to attempt to negotiate a port
channel (EtherChannel) using 802.3ad Link Aggregation Control Protocol (LACP). If LACP
negotiation fails, the vNet operates in fault tolerance mode only. Similar to the operation of NIC
Teaming, Virtual Connect will utilize one VC uplink port as the active port and all other VC uplink
ports will be in standby (blocking) mode. This behavior is part of the loop prevent mechanism of VC
(see section entitled “Virtual Connect’s Loop Prevention Technology”). See figure below as an
example.
Figure 4. A vNet Configured for Fault Tolerance only
(see Appendix A for a description of the elements in the above diagram)
An administrator can choose to manually configure a vNet (or Shared Uplink Set) for only fault
tolerance by setting the vNet’s connection mode to ‘failover’. When a vNet’s connection mode is
set to ‘failover’, the LACP protocol is disabled for the vNet and the administrator can change the
VC uplink “Port Role” to “Primary” or “Secondary”. This port role setting allows the administrator to
manually choose which VC uplink should be the preferred active uplink.
Note:
For a sample configuration showing VC uplinks connected to a Cisco switch, see the section below
entitled “Sample Virtual Connect Ethernet and Cisco Configurations”
A vNet (or Shared Uplink Set) will failover from one uplink to another whenever the active uplink loses
link. As soon as VC detects link loss on the active uplink, VC will choose a new active uplink from the
group of available standby uplinks also assigned to the same vNet. This process of choosing a new
active uplink typically occurs in under five seconds. If the upstream Cisco switch has been properly