ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

Ports and trunking 32
Trunk group configuration rules
The trunking feature operates according to specific configuration rules. When creating trunks, consider the
following rules that determine how a trunk group reacts in any network topology:
• All trunks must originate from one device, and lead to one destination device. For example, you cannot
combine a link from Server 1 and a link from Server 2 into one trunk group.
• Any physical switch port can belong to only one trunk group.
• Trunking from non-HP devices must comply with Cisco® EtherChannel® technology.
• All trunk member ports must be assigned to the same VLAN configuration before the trunk can be enabled.
• All trunk member ports must be set to full duplex mode.
• All trunk member ports must be configured for the same speed.
• If you change the VLAN settings of any trunk member, you cannot apply the change until you change the
VLAN settings of all trunk members.
• When an active port is configured in a trunk, the port becomes a trunk member when you enable the trunk
using the /cfg/l2/trunk/ena command. The spanning tree parameters for the port then change to
reflect the new trunk settings.
• All trunk members must be in the same spanning tree group and can belong to only one spanning tree
group. However if all ports are tagged, then all trunk ports can belong to multiple spanning tree groups.
• When a trunk is enabled, the trunk spanning tree participation setting takes precedence over that of any
trunk member.
• You cannot configure a trunk member as a monitor port in a Port Mirroring configuration.
• A monitor port cannot monitor trunks; however, trunk members can be monitored.
Port trunking example
In this example, the Gigabit uplink ports on each GbE2 Interconnect Switch, and the crosslink ports are
configured into a total of five trunk groups: two on each GbE2 Interconnect Switch, and one trunk group at the
crosslink between the two GbE2 Interconnect Switches. All ports operate at Gigabit Ethernet speed.
NOTE: The actual mapping of switch ports to NIC interfaces is dependant on the operating system software,
the type of server blade, and the enclosure type. For more information, see the HP ProLiant BL p-Class GbE2
Interconnect Switch User Guide.