CONTENTS

Policy on Intellectual Property Right (IPR)     ii
Series of ITU-R Reports     ii
1 Introduction  3
2 Satellite system reference models  3
        2.1 Point-to-point links  3
        2.2 VSAT networks  3
                  2.2.1 Star topology  3
                  2.2.2 Mesh topology  4
        2.3 Broadband access  4
3 TCP limitations over satellite links  5
        3.1 Bandwidth-delay product 5
        3.2 Slow start and congestion avoidance  6
        3.3 Fast retransmit and fast recovery  7
        3.4 Effect of bit errors on TCP throughput 8
        3.5 Asymmetric networks  8
        3.6 Advice to designers  9
4 TCP enhancement methodologies  9
        4.1 Variations of baseline TCP  9
        4.2 Segment splitting methodologies  16
                  4.2.1 Two-segment splitting methodology  16
                  4.2.2 Three-segment splitting methodology  17
                  4.2.3 Discussion  19
        4.3 Caching and spoofing  19
                  4.3.1 Caching  19
                  4.3.2 Spoofing  19
                  4.3.3 Spoofing and caching  19
5 Performance enhancing proxies  20
        5.1 TCP spoofing  21
        5.2 TCP splitting  21
        5.3 Other PEP mechanisms  21
        5.4 Implications of using PEP  22
                  5.4.1 End-to-end security  22
                  5.4.2 End-to-end reliability  22
6 Other transmission control protocols  22
        6.1 Space communication protocol specification � transport protocol (SCPS-TP) 22
        6.2 Xpress transport protocol 22
        6.3 Stream control transmission protocol 23
        6.4 Comparison between transmission control protocols  24
 7     Conclusion  24