Cisco routers remain the backbone of internet connections worldwide. Deep in the heart of networks, core routers perform the essential plumbing of the web. Further out on the edges, access routers provide connectivity for mobile devices via microwave radios (many of which are Eclipse radios from Aviat Networks). Generally, routers assume a full 1 Gbps bandwidth capability between Layer 2 connections provided by microwave radios.
However, modulation and channel size selections can vary the actual bandwidth between 1 Mbps and 1000 Mbps (i.e., 1 Gbps). This can also happen when Adaptive Coding Modulation (ACM) is activated on a point-to-point microwave link and the link’s bandwidth varies based on propagation conditions. If congestion occurs on the link, the router cannot quickly prioritize traffic nor select the optimal path, resulting in possible “black holing” of critical traffic.