Chapter 7. Configure Network Bonding
Red Hat Enterprise Linux 7 allows administrators to bind multiple network interfaces together into a single, bonded, channel. Channel bonding enables two or more network interfaces to act as one, simultaneously increasing the bandwidth and providing redundancy.
Warning
The use of direct cable connections without network switches is not supported for bonding. The failover mechanisms described here will not work as expected without the presence of network switches. See the Red Hat Knowledgebase article Why is bonding in not supported with direct connection using crossover cables? for more information.
Note
The active-backup, balance-tlb and balance-alb modes do not require any specific configuration of the switch. Other bonding modes require configuring the switch to aggregate the links. For example, a Cisco switch requires EtherChannel for Modes 0, 2, and 3, but for Mode 4 LACP and EtherChannel are required. See the documentation supplied with your switch and see https://www.kernel.org/doc/Documentation/networking/bonding.txt
7.1. Understanding the Default Behavior of Controller and Port Interfaces
When controlling bonded port interfaces using the
NetworkManager daemon, and especially when fault finding, keep the following in mind:
- Starting the controller interface does not automatically start the port interfaces.
- Starting a port interface always starts the controller interface.
- Stopping the controller interface also stops the port interfaces.
- A controller without ports can start static
IPconnections. - A controller without ports waits for ports when starting
DHCPconnections. - A controller with a
DHCPconnection waiting for ports completes when a port with a carrier is added. - A controller with a
DHCPconnection waiting for ports continues waiting when a port without a carrier is added.
