nt to the TCP protocol has been developed. The aim is to reach robust and stable networking at 100 Gbps and higher speeds. The protocol is a source algorithm which is called 'fast active queue management scal- able TCP/IP' or FAST/IP. See for examplehttp://netlab.caltech.edu/FAST/overview.htmi The protocol is especially interesting for research, enterprise and ISP needs. The largest difference compared with ordinary TCP is the smooth behaviour of the speed adaptation to the network capacity limitations, based on measurements of the delay between sent packet and acknowledgement. Preliminary results indicate a significant increase in transfer speed and utilization factor of existing Internet capacity. To summarize the TCP aspects: TCP/IP is used much more widely than it was designed for. There are obvious risks that the user can perceive the problems that may arise. The network designer must therefore look for evolving improvements, in order to maintain or improve user satisfaction. Security Securing connections with IPsec should be done end to end if possible. As mentioned above a split of a TCP path into more path sections might give a shorter bandwidth-delay product. The split could be done by means of a proxy server, but such solution creates a non-wanted split in the IPsec path as well. See Figure 7.12. 7.4.7 COMPRESSION OF IP VOICE PACKETS BY ROHC It could be expected that a strong header compression should lead to a decreased QoS, at least in environments with degradations. For ROHC, however, there are also positive effects, according to Figure 7.13. Mobile Internet network Mobile terminal Proxy Server TCP proxy splits the end-to-end path into two parts Proxy separates the part with long delays (radio network from the part with packet losses (Internet)) Proxy cannot be used with end-to-end IPsec Figure 7.12 QoS and security in conflict Quality of Service Compression results Original header Payload The 40 octet IPv4/UDP/RTP or 60 octet IPv6/UDP/RTP headers can be compressed down to a minimal size of 1 octet A