HP Virtual Connect for c-Class BladeSystem Version 3.00 Setup and Installation Guide for HP Integrity BL8x0c i2 Series Server Blades, Fifth Edition

Installation 57
Factory default settings
The Virtual Connect Delete Domain operation returns all VC-FC modules to the factory default settings.
VC-FC modules that are physically removed from a VC domain can be returned to the factory default
settings when placed into a new enclosure by applying power, and then pressing and holding the reset
button on the front panel for at least 10 seconds. When moved from a VC domain and placed into an
enclosure not part of a VC domain, VC-FC modules retain assigned mappings until reset to the factory
default.
Loop prevention
When link is established on a for HP Integrity BL8x0c i2 Series Server Blades port, the port exchanges
LLDP packets with the far-side connection. This LLDP protocol is an IEEE 802.1 standard that makes use of
special BPDU packets that are not forwarded by Ethernet bridges or switches. As part of the LLDP
exchange, Virtual Connect can determine whether a for HP Integrity BL8x0c i2 Series Server Blades port
is connected to another port within the same Virtual Connect domain. If the port is connected, the port is
designated as a stacking link and treated as such. If the port is not connected, then the port is available
for use as an uplink port.
Only ports that have not been designated as an uplink port in a network are eligible to become stacking
links. If a port has been designated as an uplink port, and then is subsequently connected to another for
HP Integrity BL8x0c i2 Series Server Blades, the port will not become a stacking link until it is removed
from the network definition as an uplink port.
To avoid network loops, Virtual Connect must first verify that only one active uplink exists per network
from the Virtual Connect domain to the external Ethernet switching environment. Second, Virtual Connect
must be 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 link, then the next best uplink will be made active.
• No loops through stacking links—If multiple for HP Integrity BL8x0c i2 Series Server Bladess are
used, they are interconnected via stacking links, which might appear as an opportunity for loops
within the VC environment. For each individual network in the Virtual Connect environment, VC will
block certain stacking links to ensure that each network has a loop-free topology.
The loop avoidance feature can not be disabled or changed. However, the preferred uplink connection
for a network can be identified when defining network uplinks.
Connecting for HP Integrity BL8x0c i2 Series Server
Blades uplinks
Each interconnect module has several numbered Ethernet connectors. All of these connectors can be used
to connect to data center switches (uplink ports), or they can be used to stack Virtual Connect modules as
part of a single Virtual Connect domain (stacking ports). See "Recommended stacking connections (on
page 55)."