Upon completion of this chapter, you will be able to answer the following questions:
• What is the difference between TCP and UDP transport layer functions?
• How does TCP and UDP use port numbers?
This chapter uses the following key terms. You can find the definitions in the Glossary.
Transmission Control Protocol (TCP)
Kishori arrives at work early to get on a video conference call on the desktop computer at her nursing station. She logs into the session about mask protocol at the hospital. As she intently listens to the presenter, she notices a few dropped words. She wonders if it is a problem with the network. Is this similar to her tablet losing the connection for a moment? But then she remembers that she is using a computer that is hardwired to the network.
Immediately after the call, she sends an email to Madhav in the IT department. Madhav comes to Kishori’s desk. She is confused because all of the devices do seem to be connected. Madhav explains that UDP and TCP are transport layer protocols that operate a little differently. He tells her that UDP is a ’best effort’ delivery system that does not require acknowledgment of receipt. UDP is preferable with applications such as streaming audio and VoIP. UDP is used for video conference calls.
Kishori had not heard of this before. Have you? In this module you will compare these protocols. Keep reading!
The transport layer include two protocols TCP and UDP. TCP is used to deliver messages reliably, whereas UDP is only concerned about getting the messages to the destination as quickly as possible.
A web server and a web client use specific protocols and standards in the process of exchanging information to ensure that the messages are received and understood. The various protocols necessary to deliver a web page function at the four different levels of the TCP/IP model are as follows:
• Application Layer Protocol – Hypertext Transfer Protocol (HTTP) governs the way that a web server and a web client interact. HTTP defines the format of the requests and responses exchanged between the client and server. HTTP relies on other protocols to govern how the messages are transported between client and server.
• Transport Layer Protocol – Transmission Control Protocol (TCP) ensures that IP packets are sent reliably, and any missing packets are resent. TCP provides proper ordering of packets received out of order.
• Internetwork Layer Protocol – The most common internetwork protocol is Internet Protocol (IP). IP is responsible for taking the formatted segments from TCP, assigning the logical addressing, and encapsulating them into packets for routing to the destination host.
• Network Access Layer – The specific protocol at the network access layer, such as Ethernet, depends on the type of media and transmission methods used in the physical network.