RackSwitch G8000 Application Guide
Chapter 4: Ports and Trunking
65BMD00041, November 2008
Before you configure static trunks
When you create and enable a static trunk, the trunk members (switch ports) take on certain
settings necessary for correct operation of the trunking feature.
Before you configure your trunk, you must consider these settings, along with specific config-
uration rules, as follows:
1. Read the configuration rules provided in the section, “Static trunk group configuration
rules” on page 65.
2. Determine which switch ports (up to eight) are to become trunk members (the specific
ports making up the trunk).
Ensure that the chosen switch ports are set to enabled. Trunk member ports must have the
same VLAN and Spanning Tree configuration.
3. Consider how the existing Spanning Tree will react to the new trunk configuration. See
Chapter 4, “Spanning Tree Protocol” for Spanning Tree Group configuration guidelines.
4. Consider how existing VLANs will be affected by the addition of a trunk.
Static trunk group configuration rules
The trunking (portchannel) 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.
Any physical switch port can belong to only one trunk group.
Trunking from third-party devices must comply with Cisco
®
EtherChannel
®
technology.
When ports become members of a trunk, configuration parameters (except ACL and QoS)
are applied per trunk. When a trunk group is formed, these parameters are configured for
the trunk ID, which overrides the port-level parameters.
All trunk member ports must be assigned to the same VLAN configuration before the
trunk can be enabled.
You cannot change the VLAN membership for a trunk group’s member port. You can
change the VLAN membership of the trunk group.
When an active port is configured in a trunk, the port becomes a trunk member when you
enable the trunk. The Spanning Tree parameters for the port then change to reflect the new
trunk settings.
