Port Channel Definition and StandardsLink aggregation is defined by IEEE 802.3ad as a method of grouping multiple physical interfaces into a single logical interface—a linkaggregation group (LAG) or port channel.A LAG is “a group of links that appear to a MAC client as if they were a single link” according to IEEE 802.3ad. In Dell Networking OS, aLAG is referred to as a port channel interface.A port channel provides redundancy by aggregating physical interfaces into one logical interface. If one physical interface goes down in theport channel, another physical interface carries the traffic.Port Channel BenefitsA port channel interface provides many benefits, including easy management, link redundancy, and sharing.Port channels are transparent to network configurations and can be modified and managed as one interface. For example, you configureone IP address for the group and that IP address is used for all routed traffic on the port channel.With this feature, you can create larger-capacity interfaces by utilizing a group of lower-speed links. For example, you can build a 50-Gigabitinterface by aggregating five 10-Gigabit Ethernet interfaces together. If one of the five interfaces fails, traffic is redistributed across theremaining interfaces.Port Channel ImplementationDell Networking OS supports static and dynamic port channels.• Static — Port channels that are statically configured.• Dynamic — Port channels that are dynamically configured using the link aggregation control protocol (LACP). For details, see LinkAggregation Control Protocol (LACP).There are 128 port-channels with 16 members per channel.As soon as you configure a port channel, Dell Networking OS treats it like a physical interface. For example, IEEE 802.1Q tagging ismaintained while the physical interface is in the port channel.Member ports of a LAG are added and programmed into the hardware in a predictable order based on the port ID, instead of in the order inwhich the ports come up. With this implementation, load balancing yields predictable results across device reloads.A physical interface can belong to only one port channel at a time.Each port channel must contain interfaces of the same interface type/speed.Port channels can contain a mix of 1G/10G/40G. The interface speed that the port channel uses is determined by the first port channelmember that is physically up. Dell Networking OS disables the interfaces that do not match the interface speed that the first channelmember sets. That first interface may be either the interface that is physically brought up first or was physically operating when interfaceswere added to the port channel. For example, if the first operational interface in the port channel is a Tengigabit Ethernet interface, allinterfaces at 10000 Mbps are kept up, and all other interfaces that are not set to 10G speed or auto negotiate are disabled.Dell Networking OS brings up the interfaces that are set to auto negotiate so that their speed is identical to the speed of the first channelmember in the port channel.404 Interfaces
