The demand for bandwidth-intensive applications and services, which involve transferring large amounts of data across networks, is driving the deployment of higher-speed switched ethernet networks in businesses.
In addition to meeting the demands of everyday corporate tasks, real-time communications like VoIP calls, video conferencing, and interactive messaging require scalable bandwidth not just in the core of the networks but also at the internet edge for uninterrupted public communications.
Two approaches can be used to meet these new demands. The first is to increase link speeds, but this solution is limited and cannot scale indefinitely.
The second approach is to provide additional physical links between switches, but the spanning tree protocol (STP) blocks all except one link to prevent switched loops in the network.
Therefore, the only reasonable solution is to use EtherChannel.
EtherChannel is a technology used in networking to bundle multiple physical links between two devices into a single logical link. By combining multiple links, EtherChannel simplifies network management and improves network performance in many different ways.
Cisco originally developed the EtherChannel technology to provide more bandwidth between the switches in the core of the networks. However, after many improvements, you can now implement it on other devices, such as routers, firewalls, or computers.
EtherChannel is commonly used in data centers and other high-bandwidth network environments where a high level of performance and reliability is required.
By bundling multiple physical interfaces into EtherChannel, the technology creates a single logical interface called a "port channel." Once configured, this logical link appears to the network as a single link to the connected devices, making it easier to manage and configure.
The port channel interface aggregates the bandwidth of the various physical interfaces to boost network capacity. Configuring it is straightforward and follows the same process as configuring any other physical port on the device. Additionally, a physical interface that belongs to one port channel cannot also participate in another one at the same time.
Important: EtherChannel only creates logical links that connect two devices. Hence, sending traffic to multiple devices through a single EtherChannel logical link is impossible; only direct connections are supported.
EtherChannel also provides redundancy by allowing the traffic to be automatically rerouted over the remaining links if one of the links fails. Load balancing is achieved by distributing the traffic across the available links based on a hashing algorithm that takes into account the source and destination MAC addresses or IP addresses.