MLAG Deep Dive: System Overview
Multi-Chassis Link Aggregation (MLAG) – the ability to terminate a Port Channel/Link Aggregation Group on multiple switches – is one of the more convoluted1 bridging technologies2. After all, it’s not trivial to persuade two boxes to behave like one and handle the myriad corner cases correctly.
In this series of deep dive blog posts, we’ll explore the intricacies of MLAG, starting with the data plane considerations and the control plane requirements resulting from the data plane quirks. If you wonder why we need all that complexity, remember that Ethernet networks still try to emulate the ancient thick yellow cable that could lose some packets but could never reorder packets or deliver duplicate packets.