7.1 Introduction to Link Aggregation Explained
Key Concepts of Link Aggregation
Link Aggregation, also known as EtherChannel or Bonding, is a method of combining multiple physical Ethernet links into a single logical link. Key concepts include:
- Link Aggregation Group (LAG): A collection of physical links treated as a single logical link.
- Load Balancing: Distributing traffic across multiple links to optimize bandwidth utilization.
- Redundancy: Ensuring network availability by providing multiple paths for traffic.
- Link Aggregation Control Protocol (LACP): A standardized protocol for negotiating and managing link aggregation.
- Static Link Aggregation: Manually configuring link aggregation without using LACP.
Link Aggregation Group (LAG)
A Link Aggregation Group (LAG) is a collection of physical Ethernet links that are combined to form a single logical link. This allows for increased bandwidth and improved redundancy. LAGs are typically configured on switches and routers to enhance network performance and reliability.
Example: In a data center, multiple 1 Gbps links between two switches can be combined into a single 10 Gbps LAG. This not only increases the available bandwidth but also ensures that if one link fails, the others can continue to carry traffic.
Load Balancing
Load Balancing in Link Aggregation involves distributing network traffic across multiple physical links within a LAG. This ensures that no single link becomes a bottleneck and maximizes the overall bandwidth utilization. Load balancing can be based on various criteria, such as source and destination IP addresses, MAC addresses, or ports.
Example: In a network with a LAG consisting of four 1 Gbps links, traffic can be distributed based on the source IP address. This ensures that different servers' traffic is spread across the links, optimizing the use of available bandwidth.
Redundancy
Redundancy in Link Aggregation ensures network availability by providing multiple paths for traffic. If one physical link fails, the traffic can be automatically rerouted through the remaining links in the LAG. This minimizes downtime and ensures continuous network operation.
Example: In a corporate network, a LAG with three links provides redundancy. If one link fails, the other two links can continue to carry traffic, ensuring that employees can still access the internet and other network resources without interruption.
Link Aggregation Control Protocol (LACP)
The Link Aggregation Control Protocol (LACP) is a standardized protocol that allows switches and routers to negotiate and manage link aggregation dynamically. LACP ensures that all devices in the LAG agree on the configuration and status of the links, providing a reliable and flexible link aggregation solution.
Example: When configuring a LAG between two MikroTik switches, LACP can be used to automatically detect and manage the links. This ensures that the switches agree on the LAG configuration and can dynamically adjust if a link fails or is added.
Static Link Aggregation
Static Link Aggregation involves manually configuring link aggregation without using LACP. This method is simpler but less flexible, as it does not provide dynamic link management. Static LAGs are often used in environments where LACP is not supported or when manual control is preferred.
Example: In a small office network, a static LAG can be configured between two MikroTik switches by manually assigning the links to the LAG. This provides increased bandwidth and redundancy without the need for LACP.