Design and Implementation of Header Compression and Packet Concatenation for Real-Time Communication Service

For real-time communication service, we propose a novel mechanism of header compression and packet concatenation called IHCPC (IP-Based Header Compression with Packet Concatenation). The goal of the proposed mechanism is to provide better bandwidth utilization for real-time service, especially for Voice over IP. The proposed mechanism has the following three main features: (1) the mechanism is based on IP protocol, and it can be applied to any network environments using IP protocol, (2) it integrates packet concatenation with header compression, (3) for header compression, IHCPC doesn’t use delta coding, so that the header recovery isn’t influenced by packet loss or delay constraint violation.

Besides, when IHCPC mechanism is applied to IPsec VPN, this mechanism also can reduce CPU load of IPsec VPN router. After such packet concatenation, the number of packets is reduced significantly, and the IPsec VPN router processes much less packets. Therefore processing CPU power can be saved for other purposes.

We also derive performance formulas to predict the performance of IHCPC mechanism, and the derived results show that the bandwidth utilization is improved significantly. At the final stage, we already implement IHCPC mechanism on Linux platform, and setup an experimental environment to verify the proposed design. The experiment results show that the CPU load of IPsec VPN router is indeed reduced, and the QoS for Voice over IP can be better maintained.