Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 429

Port Channel Interfaces Port channel interfaces support link aggregation, as described in IEEE Standard 802.3ad. This section covers the following topics: • Port Channel Definition and Standards • Port Channel Benefits • Port Channel Implementation • Configuration Tasks for Port Channel Interfaces 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 the 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. 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 30-Gigabit interface by aggregating three 10-Gigabit Ethernet interfaces together. If one of the three interfaces fails, traffic is redistributed across the remaining interfaces. Port Channel Implementation The system 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). Up to 128 port- channels with sixteen 10GbE or 40GbE port members per channel are supported. As soon as you configure a port channel, the system 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 or 40 Gigabit Ethernet interfaces. The interface speed (10, 40 Gbps) the port channel uses is determined by the first port channel member that is physically up. The system disables the interfaces that do match the Interfaces 429