During the TCP three-way handshake process, the following fields are negotiated:
A . Sequence number: Initial sequence numbers are established during the handshake to keep track of the segments in the communication.
C . Window size: This determines the amount of data that can be sent before receiving an acknowledgment.
G . Acknowledgment number: This confirms receipt of the data and also indicates the next expected byte.
The other options are not negotiated during the three-way handshake:
B . MTU (Maximum Transmission Unit): This is determined at the network layer and is not negotiated during the handshake.
D . MSS (Maximum Segment Size): This is communicated during the handshake but not negotiated; it's declared by the sender to inform the receiver of the maximum segment size it can handle.
E . TTL (Time To Live): This is set in each IP packet to limit its lifespan and is not negotiated during the handshake.
F- Flags: Specific flags are used during the handshake (SYN and ACK), but they are not "negotiated" per se.
H) CRC (Cyclic Redundancy Check): This is used for error-checking in frames at the data link layer and is not part of the three-way handshake.