Theoretically, MPTCP’s approach is sound. However, practical deployment reveals a significant challenge: TCP within TCP requires the bonded lines to exhibit closely matched performance characteristics. This requirement becomes problematic with fluctuating WAN link conditions, a common scenario for cellular connections which inherently vary over time.

In environments where WAN link performance is not uniform, MPTCP’s efficiency tends to degrade. This is particularly true for applications where reliability is paramount. For these scenarios, a specialized solution is necessary. Broadband bonding overlay tunnels represent a more tailored approach, offering robust performance even under varying network conditions.

At my company, where we specialize in developing Broadband Bonding Network Appliances (BBNA), we’ve observed substantial performance improvements with our solutions, especially in mission-critical applications. This underscores the importance of choosing the right network solution to match the specific requirements of the use case.