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  1.   Trademarks
  2. 1 Introduction
    1. 1.1 License
    2. 1.2 IwIP Version
    3. 1.3 lwIP Customization
    4. 1.4 IwIP API
      1. 1.4.1 TCP RAW APIs
      2. 1.4.2 UDP RAW APIs
    5. 1.5 lwIP Development Home Page and Support
  3. 2 Application Examples
  4. 3 Application Setup
    1. 3.1 Hardware Setup
    2. 3.2 Software Tools
  5. 4 Download and Import the Ethernet examples
  6. 5 Enet_tcpecho_server_lwip Example Overview
    1. 5.1 Build and Flash the Program
    2. 5.2 Check and Program the MAC Address
      1. 5.2.1 Using The LM Flash Programmer
      2. 5.2.2 Using the CCS
      3. 5.2.3 Using Uniflash
    3. 5.3 Configure the Terminal Window
    4. 5.4 Run the enet_tcpecho_server_lwip Example
  7. 6 Enet_tcpecho_server_static_ip_lwip Example Overview
    1. 6.1 How to Configure lwIP for Static Address
    2. 6.2 Run the enet_tcpecho_server_static_ip_lwip Example
  8. 7 Enet_udpecho_server_lwip Example Overview
    1. 7.1 Run the enet_udpecho_server_lwip Example
  9. 8 Enet_dns_lwip Example Overview
    1. 8.1 How to Configure lwIP for DNS
    2. 8.2 How to View the DNS Traffic on Wireshark
    3. 8.3 Run the enet_dns_lwip Example
  10. 9 Enet_sntp_lwip Example Overview
    1. 9.1 Run the enet_sntp_lwip Example
  11. 10Enet_tcpecho_client_lwip Example Overview
    1. 10.1 Configure the Server IP Address
    2. 10.2 Configure the SocketTest Server and Run the enet_tcpecho_client_lwip Example
    3. 10.3 Wireshark Capture for enet_tcpecho_client_lwip Example
  12. 11Enet_adcsensor_client_lwip Example Overview
    1. 11.1 Run the adcsensor_client_lwip Example
  13. 12Enet_udpecho_client_lwip Example Overview
    1. 12.1 Run the enet_udpecho_client_lwip Example
  14. 13References

10 Enet_tcpecho_client_lwip Example Overview

The enet_tcpecho_client_lwip example demonstrates a client application that first connects to the server with a greetings message “Hello World!\n\r” and then echoes back whatever it receives from the server.

As illustrated in lwIP flowchart for TCP in Figure 1-1, the client will use tcp_connect() to connect to the specified server address and port. Once the connection is established, the client will use tcp_recv() to setup a callback function for receiving data from the server and then echo the data back.

Another difference between the client and server in the flowchart is that the client doesn’t need to call tcp_bind(). Binding is normally not needed on the client side for TCP. There may be circumstances where binding the client is needed in which you will use tcp_bind() to bind the client. An example would be a firewall on the client that only allows outgoing connections on a certain port.