OS X Mountain Lion: Combine Ethernet ports
If you have a computer with more than one Ethernet port, you can combine them into one virtual Ethernet port. This is known as “link aggregation.” The combined Ethernet ports appear as a single IP address to your computer and apps.
Combining ports provides increased bandwidth by merging the bandwidth of the individual ports. Network traffic is also balanced across the ports.
In addition to balancing network traffic, combining ports provides automatic backup if one port or cable fails. All traffic that was routed over the failed port is rerouted to one of the remaining ports. This backup is automatic, and apps using the port continue without interruption.
If the Ethernet ports you want to combine are on a PCI card installed in your computer, make sure the card is installed properly before combining the ports. See the documentation that came with the PCI card for instructions about installing it.
- Choose Apple menu > System Preferences, and then click Network.
- Choose Manage Virtual Interfaces from the Action pop-up menu (looks like a gear) at the bottom of the network connection services list.
- Click Add (+), and then choose New Link Aggregate.
- Select the Ethernet ports you want to combine, give the aggregate service a name, and then click Create.
- Click Apply to activate the new virtual Ethernet service.
After the Ethernet ports have been linked, you can check the status of the link by looking at the icon in the network connection services list. For more detailed information about the aggregated link status, click one of the ports in the list.
OS X uses the Link Aggregation Control Protocol (LACP) to negotiate the link aggregation. LACP must be supported on all link aggregation devices involved.