Specifications

HP Virtual Connect for Cisco Network Administrators (version 1.2x) page 29
for the vNet and the port channel will be active. As a result, both port channels are active. No loop
results since VC does not permit frames to jump between vNets. Since both port channels are
active, the VC Domain has a 4 Gb connection to VLAN 1 (2 port channels x 2 Gb each).
In order to utilize both port channels, the servers can be divided between the two vNets or each
server can be connected to both vNets using NIC Teaming (as the figure below depicts). When
each server is connected to both vNets using NIC Teaming, the load balancing algorithm in the NIC
Teaming driver controls how data frames are load balanced over each vNet.
Figure 12. VC Domain Showing Advanced Usage of vNets and EtherChannel
(see Appendix A for a description of the elements in the above diagram)
Advanced VC-Enet Designs: Example Design #3
In this example, blade servers 1 and 16 need to be connected to different VLANs on the external
network with a 4 Gb pipe. However, ports from different VC modules need to be used to eliminate
single points of failure (redundant VC modules). If two uplink ports from module 1 and two uplink
ports from module 2 are assigned to the same vNet, then VC forms two port channels (two logical
paths). As was discussed in the section entitled ‘VC Uplink Load Balancing”, VC must prevent loops
on the network so only one logical path will be active at a time. This means the server’s bandwidth
is reduced from 4 Gb to 2 Gb since one whole port channel is placed in standby mode.
To solve this problem, two Shared Uplink Sets are used instead of one. Each Shared Uplink Set is
assigned the uplink ports for a single port channel. Since each Shared Uplink Set only has a single
port channel, there is only one logical path for the Shared Uplink Set and the port channel will be
active. As a result, both port channels are active. No loop results since VC does not permit frames
to jump between vNets in the same Shared Uplink Set nor does VC permit frames to jump between
vNets in different Shared Uplink Sets. Since both port channels are active, the VC Domain has a