An All-MPLS Approach for UMTS 3G Core Networks

In this paper, we present an all-MPLS approach for UMTS 3G core networks. GTP-tunnel has been defined by 3GPP as the transport mechanism for UMTS. For each packet transmission, extra GTP, UDP, and IP headers (40-byte) are required. For short packets, such as VoIP payloads, transmission overhead is very high. Enhanced-GTP was proposed to eliminate the need for a GTP header. Since its operation mode is limited to non-transport mode only, NAT is required in GGSN. Furthermore, its performance improvement is limited, because an extra IP header (20-byte) is still needed. In response to these drawbacks, we propose to integrate MPLS technology to UMTS 3G core networks. We use MPLS-tunnel as the transport mechanism by using two-level MPLS labels (8-byte) to replace the GTP-tunnel. To the best of our knowledge, this is a novel approach, since no MPLS-based approach was ever proposed for UMTS 3G core networks. Our approach is feasible, since more and more routers are MPLS-capable. By reducing header overhead from 40-byte to 8-byte, our new approach improves transmission efficiency from 56.5% ~ 63% to 86.6% ~ 89.5% for VoIP payloads and also enhance packet forwarding efficiency. In addition, our all-MPLS approach offers better load balancing, better service resilience, and better QoS support, compared to existing approaches.