Context-aware QoS management is a new research field dealing with methods by which traditional QoS management algorithms in mobile and fixed networking systems can have more intelligent decision-making mechanisms by fully exploiting all context information being available in their network environment. Motivated by addressing the critical problem, we propose a novel context-aware cognitive QoS management approach, which contains three main steps for context discretization, context reduction and QoS guarantee, which can provide the quantitative end-to-end QoS guarantee and management. We developed a context-aware systematic end-to-end QoS management module in a real-life multimedia conferencing system and compared its performance with existing approaches. Experimental results show that our proposed approach outperforms the existing approaches in improving the mobile and fixed networking video transmission quality.