Need tunneling for TCP packets

[yunkon-kim]

Current CB-Net (PoC) makes a common subnet.

VMs using the common subnet can communicate with each other by tunneling.

Now, CB-Net supports UDP packets. For example,

1. Read UDP packet (Later, TCP packet could be read)
2. Encapsulate the packet by UDP header (No change this)
3. Send it to the destination

It's not easy for me to decide to add tunneling for TCP packets.

If necessary, it will be added later.

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[seokho-son]

@hermitkim1
TCP tunneling (패킷 인켑슐레이션시 TCP 사용?) 이 왜 필요할까요?
UDP를 사용하여 터널링을 하면 신뢰도가 낮기 때문? 아니면.. 보통 UDP 포트를 방화벽에서 막기 때문? ^^

[FYI]
by https://www.researchgate.net/publication/238445492_Understanding_TCP_over_TCP_effects_of_TCP_tunneling_on_end-to-end_throughput_and_latency

TCP tunnel is a technology that aggregates and transfers packets sent between end hosts as a single TCP connection. By using a TCP tunnel, the fairness among aggregated flows can be improved and several protocols can be transparently transmitted through a firewall. Currently, many applications such as SSH, VTun, and HTun use a TCP tunnel. However, since most applications running on end hosts generally use TCP, two TCP congestion controls (i.e., end-to-end TCP and tunnel TCP) operate simultaneously and interfere each other. Under certain conditions, it has been known that using a TCP tunnel severely degrades the end-to-end TCP performance. Namely, it has known that using a TCP tunnel drastically degrades the end-to-end TCP throughput for some time, which is called TCP meltdown problem. On the contrary, under other conditions, it has been known that using a TCP tunnel significantly improves the end-to-end TCP performance. However, it is still an open issue --- how, when, and why is a TCP tunnel malicious for end-to-end TCP performance? In this paper, we therefore investigate effect of TCP tunnel on end-to-end TCP performance using simulation experiments. Specifically, we quantitatively reveal effects of several factors (e.g., the propagation delay, usage of SACK option, TCP socket buffer size, and sender buffer size of TCP tunnel) on performance of end-to-end TCP and tunnel TCP.

[FYI]
by https://www.researchgate.net/publication/304287577_Experimental_performance_comparison_between_TCP_vs_UDP_tunnel_using_OpenVPN

In this work, we use OpenVPN as a platform to demonstrate the performance between TCP/UDP. The de facto belief has been that TCP tunnel provides a permanent tunnel and therefore ensures a reliable transfer of data between two end points. However the effects of transmitting TCP within a UDP tunnel has been explored and could provide a valuable attempt. The results provided in this paper demonstrates that indeed TCP in UDP tunnel provides better latency. Throughout this paper, a series of tests have been performed, UDP traffic was sent inside UDP tunnel and TCP tunnel successively. The same tests was performed using TCP traffic.

[yunkon-kim]

@seokho-son
코멘트 및 정보 공유 감사합니다 😄

"TCP tunneling (패킷 인켑슐레이션시 TCP 사용?) 이 왜 필요할까요?"와 관련하여 말씀드립니다.

본래 의도는 현재 UDP Packet을 읽어 UDP로 Tunneling을 하고 있기 떄문에 TCP Packet을 읽어 UDP Tunneling 하는 부분을 하고자 했던 것입니다.

제목을 정정해놓겠습니다.