EtherChannel is a Port Aggregation technology that groups the connection structure of multiple physical Ethernet ports into a single logical connection.
Cisco EtherChannel Technology
More bandwidth and redundancy are needed in the network connection structure of large or small companies. Due to such reasons, more than one cable connection can be established between Switches to prevent any data loss.
EtherChannel is a Cisco proprietary technology created by the improvements made by Kalpana company acquired by Cisco in the 1990s to keep the scalability and consistency level of the network at a high level.
Cisco developed the EtherChannel structure to group multiple FastEthernet or GigabitEthernet ports into a single logical channel. As a result of its later developments, this technology was named Link and Port Aggregation specified in the IEEE 802.3ad standard.
Spanning Tree Protocol, which is active by default on Cisco Layer 2 Switches, prevents loops that may occur by redundant paths between switches in the network. However, Port Aggregation, or EtherChannel, can be configured among the devices that will not be blocked by STP.
If more than one EtherChannel group is created between two Switches, the STP protocol will block one of the groups created to prevent loops. As a result, if one of the redundant connections is blocked, the entire EtherChannel structure of the group belonging to that port will be blocked.
STP sees one or more physical port connections, divided into logical groups, as just one link.
As EtherChannel provides load sharing, efficient bandwidth, and redundancy among servers, switches, and routers, it increases the speed of data communication between devices and minimizes the delays that may occur on the network by logically combining the physical ports of the switches.
When EtherChannel is configured between switches in the network, the created virtual interface is called Port Channel.
EtherChannel has many advantages in local networks;
A Switch configured as EtherChannel provides redundancy and efficiency in data communication on the network.
There is no need to purchase any extra hardware to have more bandwidth. Therefore, multiple physical interfaces of the switches are logically configured for more bandwidth. For example, if 8 GigabitEthernet interfaces are configured as EtherChannel on a device, the bandwidth will be 8 Gb/s.
It provides load balancing in data communication.
It provides load balancing based on source and destination MAC addresses and source and destination IP addresses.
Since it is seen as a single logical structure when a cable belonging to one of the groups between devices fails or breaks, there is no change in the topology and the traffic flow continues. In such a case, Spanning Tree will not be recalculated.
The port types of the network devices to be implemented with EtherChannel must be the same, ie FastEthernet and GigabitEthernet interfaces cannot be created in a single group. A group created only between devices with the same port type will be acceptable.
In newer Switch types, the number of groups to be created is 8. However, this number may be 6 in older models. In short, this number can be increased depending on the structure of the network device and the hardware performance.
Since the Port Aggregation configuration between two switches in the network environment is up to 8 ports, the total bandwidth speed of the FastEthernet structure will be 800 Mbps, while the GigabitEthernet structure will be 8 Gbps.
Hence, the logical grouping process created must be the same on both devices. If it is configured to pass VLANs between these devices, the port connection structure for the native VLAN must be Trunk.