1) PTGATE is an application gateway developed to deploy high-quality video communications in various network environments during the transition from IPv4 to IPv6. 2) PTGATE uses techniques like IP-in-IP encapsulation and error recovery to allow existing videoconferencing systems to work over IPv6 networks. 3) Evaluation of PTGATE showed it could support various videoconferencing systems, establish multicast tunnels, and introduce minimal overhead while maintaining high throughput and low latency.

1. An Application Gateway to Deploy High-quality Video Communications in Various Network Environments Takashi Kishida Kaori Maeda Eitaro Kohno Yoshiaki Kakuda

7. Outline of the system process Router B Router A Internet Sender Receiver Port aggregation IPv6/IPv4 tunneling FEC encoding Decapsulation FEC decoding The Sender and the Receiver are videoconference systems PTGATEs are located in the same subnet of the Sender and the Receiver, respectively. The default gateway of the Sender is set to PTGATE A All packets from the Sender are sent to PTGATE A PTGATE checks the destination PTGATE A PTGATE B IP UDP PTGW IP Payload IP UDP PTGW IP Payload

11. Practical Experiments I - Multicast tunnel audio conferencing system MRAT(128kbps) Multicast Hiroshima Univ. Hiroshima City Univ. Saga Univ. Multicast Multicast Multicast Not supporting multicast Interoperability problems misconfigured routers

12. Practical Experiments I - Multicast tunnel Hiroshima Univ. Hiroshima City Univ. Saga Univ. Multicast Multicast Multicast audio conferencing system MRAT(128kbps) Multicast PTGATE PTGATE PTGATE ： Multicast Tunnel

13. Practical Experiments II - IPv6/IPv4tunnel JGNv6 Network RIBB2 Network Hiroshima City Univ. Yamanashi Toyama Kochi Sapporo IPv6 IPv4 IPv4 encapsulation IPv4 decapsulation Receiver Receiver Receiver Sender Sapporo Snow Festival PTGATE PTGATE PTGATE PTGATE Multicast IPv6 Multicast IPv6

14. Practical Experiments II – Receivers result 1.1396 0.8750 1.1020 Jitter (ms) 0.0033 0.0034 0.0032 Packet loss rate [%] (After an error recovery) 0.4504 0.4504 0.4493 Packet loss rate [%] (Before an error recovery) 438 446 429 Lost packets (After an error recovery) 59738 59737 59694 Lost packets (Before an error recovery) Yamanashi Kochi Toyama

15. Performance Evaluation - Experimental environment Host A Host B Router AT AR450s PTGW B PTGW A Subnet A Subnet B 192.168.1.0/24 192.168.2.0/24 100baseTX 100baseTX Iperf (payload1400byte Transmitting time 60 sec) 384MB 1024MB 1024MB 512MB Memory PentiumⅢ 1GHz Pentium4 3.2GHz Pentium4 3.2GHz PentiumⅢ 1GHz CPU Fedora core 3 Fedora core2 RedHat 8.0 VineLinux 3.1 OS Host B PTGW B PTGW A Host A

16. Performance Evaluation - UDP Throughput Host A Host B Router AT AR450s PTGW B PTGW A Subnet A Subnet B 192.168.1.0/24 192.168.2.0/24 100baseTX 100baseTX Iperf (payload1400byte Transmitting time 60 sec) UDP: 95.0 Mbps UDP: 92.7 Mbps Not using PTGATE Using PTGATE - 2.3 Mbps

18. Performance Evaluation - RTT Host A Host B Router AT AR450s PTGW B PTGW A Subnet A Subnet B 192.168.1.0/24 192.168.2.0/24 100baseTX 100baseTX RTT: 1.6 ms RTT: 2.3 ms Ping ICMP payload length : 1400 bytes Transmitting time : 240 sec Not using PTGATE Using PTGATE +0.7 ms

19. Performance Evaluation - Jitter Host A Host B Router AT AR450s PTGW B PTGW A Subnet A Subnet B 192.168.1.0/24 192.168.2.0/24 100baseTX 100baseTX Jitter: 0.04 ms Jitter: 0.11 ms Iperf Bandwidth : 8 Mbps Payload length : 1400 byte Transmission time : 60 sec Not using PTGATE Using PTGATE +0.07 ms

20. Performance Evaluation - Overhead of FEC 0 10 20 30 40 50 60 70 80 90 100 0 20 40 60 80 100 Sending data rate (Mbps) Receiving data rate (Mbps) RS(15,14) RS(15,13) RS(15,12) No FEC CPU: Pentium4 3.2GHz 1.108 times 1.193 times 1.293 times 42.4 Mbps 36.0 Mbps 26.1 Mbps The growth rate of the bandwidth