Service Manual

Port Channel Implementation
Dell 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, refer to Link Aggregation 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 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 line card resets and chassis 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 10, 100, or 1000 Mbps Ethernet interfaces and Gigabit Ethernet
interfaces. The interface speed (10, 100, or 1000 Mbps) the port channel uses is determined by the first
port channel member that is physically up. Dell Networking OS disables the interfaces that do match the
interface speed that the first channel member sets. That first interface may be the first interface that is
physically brought up 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 Gigabit Ethernet interface, all interfaces
at 1000 Mbps are kept up, and all 10/100/1000 interfaces that are not set to 1000 speed or auto
negotiate are disabled.
Dell Networking OS brings up 10/100/1000 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.
10/40 Gbps Interfaces in Port Channels
When 10/40 Gbps 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. At that time, 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 Networking OS disables them.
Configuration Tasks for Port Channel Interfaces
To configure a port channel (LAG), use the commands similar to those found in physical interfaces. By
default, no port channels are configured in the startup configuration.
These are the mandatory and optional configuration tasks:
• Creating a Port Channel (mandatory)
• Adding a Physical Interface to a Port Channel (mandatory)
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Interfaces