TCP 3 way Handshake Query

[prakashrajasekaran2807]

Hi Folks,

A pc connects to google.com and also uses an FTP service and also email servers are logged in at the same time. How TCP three Handshake works in this scenario. When Multiple types of services are used at times how does PC identify which ACK is for which services?  

[MHM Cisco World]

Each traffic seq number set when pc start new tcp session.

[Jon Marshall · Accepted solution]

TCP keeps track of the connections with the port numbers eg a PC connecting to a server running multiple services works because each service has a different port so the combination of PC IP and PC port (random)  server IP and server port are unique to that connection. 

Even if the same PC connects to the same service multiple times on the same server each connection is unique because for each connection the source port on the PC will be a different one. 

Jon