TCP Connection Management

Recall: TCP sender, receiver establish “connection” before exchanging data segments

• initialize TCP variables:

  • seq. #s
  • buffers, flow control info (e.g. RcvWindow)

• client: connection initiator

Socket clientSocket = new Socket("hostname","port number");

• server: contacted by client

Socket connectionSocket = welcomeSocket.accept();

Three way handshake:

Step 1: client end system sends TCP SYN control segment to server

• specifies initial seq #

Step 2: server end system receives SYN, replies with SYNACK control segment

• ACKs received SYN
• allocates buffers
• specifies server-> receiver initial seq. #

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