TCP/UDP connection

[nsmaddict]

Hi All,

I know this question will sound little stupid but i still want to clarify since i am getting struck in one of my design.
Kindly explain me how is the session negotiated? You can take an ex of any service : http, ftp etc.Starting from broadcast to syn, ack and everything.
2. If the session is established in the case of TCP then once the reciever has accepted the data then what does it do and reply back?I have the idea that based on the request the reciever accepts the data and execute the query and reply back to the sender.Let me know the detailed description.
3.How abt the same thing in UDP?

I know the only diff comes in both is that UDP session does not send ACK for any data transmission.I will be grateful if anyone can provide me the detailed description about these queries.Waiting for the response.

Neelima

 

[JoeBloggssss]

Hi,

Session establishment is a three stage process for TCP.

Client A ----> SYN Client B
Client A <---- SYN/ACK Client B
Client A ----> ACK Client B

This is the session established. This process requires for all communications. Also, packet flags such as RST (Reset), and FIN (Finished) are used to terminate or end a communication. The RST resets a connection, say I SYN scan all your ports, and it rejects the connection. However, some os do not reply in this manner. TCP uses Sequence numbers to keep track of the order of packets, and especially if they are larger than MTU 1500, and requires fragmentation. UDP does not have ACK functionality, it is used for non-session multicast traffic.