From the course: Learning the Packet Delivery Process

Explore the TCP/IP model

From the course: Learning the Packet Delivery Process

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Explore the TCP/IP model

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- The TCP/IP model and related TCP/IP stack were built to allow computers and other devices to communicate reliably over large distances. The TCP/IP model offers another option for understanding how data is delivered across a network, and differs from the OSI model you may be more familiar with. The TCP/IP model is a protocol oriented model and provides practical standards for data delivery. The OSI model offers more general guidance and is not protocol based. The TCP/IP model incorporates the rules created when the internet was developed. And thus, can also explain the actual processes used in data delivery. The names of the layers in this model are not set in stone, unfortunately, and this can cause confusion when first learning about it. Additionally, some say there are five layers, not four. These are the most common names for the four layers: application, transport, internet and network access. And you can see how they relate to the OSI model here. As you can see here, there are alternate names for these layers. Application is sometimes called application presentation, transport sometimes host to host, internet sometimes network and networking and network access sometimes data link, physical, network interface, and link. The application layer interacts with the programs people and computers use to perform tasks. Applications include web browsers, accounting software, photo editing software, and so on. Applications also provide access to network resources, virtual private networks and other online or internet based resources. You can see your apps from start, settings and apps. The protocols used at this layer are HTTP and HTTPS for surfing the web. SSH for maintaining an encrypted connection. And NTP used to synchronize clocks on computers and other nodes. The transport layer is responsible for transporting source data to its destination. This layer determines how much data should be sent, where it's sent, and how quickly it should travel. Two protocols used in this layer are TCP and UDP. TCP provides reliable data delivery among systems and performs acknowledgment features and flow control. This results in a lot of overhead and leads to increased cost. TCP is used when data needs to arrive in order and in sequence. UDP also delivers data, but doesn't have all of the overhead TCP does. UDP is more cost-effective, but doesn't offer a reliable transport of data. The internet layer is responsible for sending data packets. This layer determines the route they will take and can transfer various types of data sequences across the internet. A few of the protocols used by this layer are IP, ICMP and ARP. IP is responsible for packet delivery. There are two versions of IP, IPV four and IPV six . IPV four and six are supported by all modern operating systems. And you can get a glimpse of that from the system window. One way is to view network connections in control panel. Here, you can right click any connected network, click properties, and click TCP/IP. Scrolling down, you can also see that IPV V six is also part of the operating system. ICMP is included with each data packet and provides information about problems with the network. It is responsible for uncovering errors with delivery. ARP is responsible for locating a device's MAC address. A MAC address is a hardcoded address assigned to hardware on a network. The assignment is made by the manufacturer of the device and is unique. You can type ARP, a space, a dash A, at a command prompt from your own computer to locate your nodes MAC addresses. ARP space dash A. You'll learn more about ARP later in this course. And finally, the network interface layer represents the physical hardware on the network. It's responsible for defining how data should be sent, and what should be used to send it. This can be co-ax cable, ethernet, Bluetooth, USB, WIFI and so on. Now that you're familiar with the TCP/IP layers, their basic responsibilities, and the protocols they use, we can now dive even deeper into each of these. Continue to learn more.

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