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How does sequence number work in TCP?
The sequence number is the byte number of the first byte of data in the TCP packet sent (also called a TCP segment). The acknowledgement number is the sequence number of the next byte the receiver expects to receive. The sequence number is always valid. The acknowledgement number is only valid when the ACK flag is one.
Does TCP drop out of order packets?
One of the functions of TCP is to prevent the out-of-order delivery of data, either by reassembling packets into order or forcing retries of out-of-order packets. These packets get dropped causing retransmission, slowdowns and out-of-order packets.
What happens when two IP packets are duplicated?
In certain situations could happen that IP packets are duplicate along the path to their destination. For example a router could decide to forward incoming traffic thorugh 2 different network interfaces. In this case could happen that both IP packets will reach the destination. TCP handle duplicated IP packets problem, so you don’t care about them.
What is the sequence number for packet 3 in TCP?
Packet #3, from the client, has only the ACK flag set. These three packets complete the initial TCP three-way handshake. The client on either side of a TCP session maintains a 32-bit sequence number it uses to keep track of how much data it has sent.
What does it mean when a TCP request is a duplicate?
There are two things you could mean be duplicate packets: duplication of the payload (the data being sent) or an exact duplicate of the payload and headers. TCP will attempt to resend data that it doesn’t receive an ACK (acknowledgement from the receiver that the packet arrived okay) for.
How does TCP protocol stack interact with data encapsulation?
The protocols at each layer on the sending host add information to the original data. As the user’s command makes its way through the protocol stack, protocols on each layer of the sending host also interact with their peers on the receiving host. The following figure shows this interaction. Data Encapsulation and the TCP/IP Protocol Stack