Dell PowerEdge FX2/FX2s - Manual (Page 100)

Port Channel Definitions 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 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.
With this feature, you can create larger-capacity interfaces by utilizing a group of lower-speed links. For
example, you can build a 40-Gigabit interface by aggregating four 10-Gigabit Ethernet interfaces
together. If one of the four interfaces fails, traffic is redistributed across the three remaining interfaces.
Port Channel Implementation
An Aggregator supports only port channels that are dynamically configured using the link aggregation
control protocol (LACP). For more information, refer to Link Aggregation. Statically-configured port
channels are not supported.
The table below lists out the number of port channels per platform.
Platform Port-channels Members/Channel
FN I/O Aggregator 128 4
As soon as a port channel is auto-configured, the 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 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 switch 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 1000 or 10000 Mbps Ethernet interfaces . The interface speed (100,
1000, or 10000 Mbps) used by the port channel is determined by the first port channel member that is
physically up. Dell Networking OS disables the interfaces that do not match the interface speed set by the
first channel member. 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 TenGigabit Ethernet interface, all interfaces at 1000 Mbps are kept up,
and all 100/1000/10000 interfaces that are not set to 1000 Mbps speed or auto negotiate are disabled.
100 Interfaces