SMC Networks 100BASE-TX, 16 10BASE-T manual Creating Trunk Groups, Command Usage

3 Configuring the Switch

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 four trunks at a time.

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 trunk, 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 four trunks on the switch, with up to eight 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.

•The ports at both ends of a trunk must be configured in an identical manner, including communication mode (i.e., speed, duplex mode and flow control), VLAN assignments, and CoS settings.

•All the ports in a trunk have to be treated as a whole when moved from/to, added or deleted from a VLAN.

•STP, VLAN, and IGMP settings can only be made for the entire trunk.

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