i-ACK

🚩⭕ Implicit ACK

Newcomer's Project for SNU CSE SCONE

Contributors

• Jiho Choi
• Onyu Kang

Installation & Instructions

Installation
Instructions

Project Overview

Modify OpenWrt for routers to generate L2 ACK and send the ACK to senders to improve throughput

Default OpenWrt

    [Server]  <------>  [AP]  <------>  [Client]

        | <----- REQ ---- | <----- REQ ---- |

        | ----- DATA ---> | ----- DATA ---> |

                          | <-- L2 ACK ---- |

          <-- L4 ACK ---- | <-- L4 ACK ---- |

Modified

    [Server]  <------>  [AP]  <------>  [Client]

        x <----- REQ ---- x <----- REQ ---- x

        x ----- DATA ---> x ----- DATA ---> x

                     [DET DATA]
                          $
                    [GEN L4 ACK]

                          x <-- L2 ACK ---- x

                    [DET L2 ACK]
                          $
                    [SND L4 ACK]

        x <--- F-ACK ---- x

                          x <-- L4 ACK ---- x
                      
                      [IGNORE]

OpenWrt Structure

(Open Embedded System for Wireless Routers)

Stack Overflow

./build_dir

is used to upack all the source archives and to compile them

• host
• toolchain
• target

./staging_dir

is used to install all the compiled programs into or for preparing the firmware image

• host
• toolchain
• target

Background Information

Network Layers - Open Systems Interconnection Model (OSI Model)

Layer	Name	Protocols
L7	Application	FTP	Data	Data
(L6)	(Presentation)
(L5)	(Session)
L4	Transport	TCP	Segments	TCPH + Data
L3	Network	IPv4	Packets	IPH + TCPH + Data
L2	Data Link	MAC	Frames	FH + IPH + TCPH + Data + FF
L1	Physical		Bits

Wireless Network - IEEE802.11

• L2 ACK : MAC ACK for Wireless (Wi-Fi) Connection
• L4 ACK : TCP ACK

TCP Congestion Control

• .

References

• OpenWrt
• OpenWrt Wiki
  • Build System
  • Cross Compile
• OpenWrt Structure
• IP Spoofing
• Wireless MAC
• Gyumin Sim's Wiki