P
ORT

C

ONFIGURATION

9-8

Creating Trunk Groups
You can create multiple links between devices that work as one virtual,
aggregate link. A port trunk offers a dramatic increase in bandwidth for
network segments where bottlenecks exist, as well as providing a
fault-tolerant link between two devices. You can create up to 12 trunks.
The switch supports both static trunking and dynamic Link Aggregation
Control Protocol (LACP). Static trunks have to be manually configured at
both ends of the link, and the switches must comply with the Cisco
EtherChannel standard. On the other hand, LACP configured ports can
automatically negotiate a trunked link with LACP-configured ports on
another device. You can configure any number of ports on the switch as
LACP, as long as they are not already configured as part of a static trunk. If
ports on another device are also configured as LACP, the switch and the
other device will negotiate a trunk link between them. If an LACP trunk
consists of more than eight ports, all other ports will be placed in a standby
mode. Should one link in the trunk fail, one of the standby ports will
automatically be activated to replace it.
Command Usage
Besides balancing the load across each port in the tru nk, the other ports
provide redundancy by taking over the load if a port in the trunk fails.
However, before making any physical connections between devices, use
the web interface or CLI to specify the trunk on the devices at both ends.
When using a port trunk, take note of the following points:
• Finish configuring port trunks before you connect the corresponding
network cables between switches to avoid creating a loop.
• You can create up to 12 trunks, with up to eight VDSL ports per trunk
or up to two Gigabit Ethernet ports per trunk.
• The ports at both ends of a connection must be configured as trunk
ports.
• When configuring static trunks on switches of different types, they must
be compatible with the Cisco EtherChannel standard.