Users Guide
Port Channel Definition and Standards
Link aggregation is defined by IEEE 802.3ad as a method of grouping multiple physical interfaces into a single logical interface—
a link aggregation 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 EMC
Networking OS, a LAG 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 the port channel, another physical interface carries the traffic.
Port Channel Benefits
A 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
configure one 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-Gigabit interface by aggregating five 10-Gigabit Ethernet interfaces together. If one of the five interfaces fails, traffic is
redistributed across the remaining interfaces.
Port Channel Implementation
Dell EMC 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 Link Aggregation Control Protocol (LACP).
The port channel ID ranges from 1 to 128.
Although the system allows you to assign more number of ports in a port channel, Dell EMC Networking recommends having a
maximum of 16 interfaces per port channel.
As soon as you configure a port channel, Dell EMC Networking OS treats it like a physical interface. For example, IEEE 802.1Q
tagging is maintained 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 in which 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
channel member that is physically up. Dell EMC Networking OS disables the interfaces that do not match the interface speed
that the first channel member sets. That first interface may be either the interface that is physically brought up first or was
physically operating when interfaces were added to the port channel. For example, if the first operational interface in the port
channel is a Tengigabit Ethernet interface, all interfaces at 10000 Mbps are kept up, and all other interfaces that are not set to
10G speed or auto negotiate are disabled.
Dell EMC Networking OS brings up the interfaces that are set to auto negotiate so that their speed is identical to the speed of
the first channel member in the port channel.
Interfaces in Port Channels
When interfaces are added to a port channel, the interfaces must share a common speed. When interfaces have a configured
speed different from the port channel speed, the software disables those interfaces.
The common speed is determined when the port channel is first enabled. Then, the software checks the first interface listed in
the port channel configuration. If you enabled that interface, its speed configuration becomes the common speed of the port
channel. If the other interfaces configured in that port channel are configured with a different speed, Dell EMC Networking OS
disables them.
Port channels can contain a mix of 1G/10G/40G. The interface speed that the port channel uses is determined by the first port
channel member that is physically up. Dell EMC Networking OS disables the interfaces that do not match the interface speed
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Interfaces