12.1. Functional architecture
In the case of LWA/LWIP aggregation solutions, the LTE (Long-Term Evolution) and Wi-Fi access aggregation is done at the eNB entity level. In MPTCP-based (Multi-Path Transmission Control Protocol) aggregation solutions, aggregation occurs at the TCP layer.
The target of MPTCP aggregation is to transmit data using multiple paths without causing modifications to existing infrastructures (the 4G mobile network, Wi-Fi access).
The MPTCP connection is performed by the MPTCP client hosted in the mobile and the MPTCP server hosted in an MPTCP proxy. The MPTCP connection is built on TCP connections, each corresponding to an access, LTE or Wi-Fi (Figure 12.1).
The TCP (Transmission Control Protocol) is a reliable protocol for the following reasons:
- – data transmission is conditional upon the establishment of a connection between the source and destination;
- – the receiver delivers ordered, error-free data to the application layer;
- – the receiver implements a source flow control mechanism based on its receive buffer occupancy;
- – the source rate is regulated based on the congestion state of the network.
The TCP is byte-stream oriented:
- – at the source side, the application writes bytes into the transmission buffer. The TCP transmits segments to the recipient;
- – at the destination ...