Nicole Faubert

Testing Next Generation Networks – A Look at OSI and TCP/IP Models

Blog Post created by Nicole Faubert Employee on Apr 24, 2018

In April 2017, one year ago to date, Keysight announced the closing of the acquisition of Ixia. It was positioned as a perfect complement for testing and monitoring next generation networking technologies. As an engineer and marketer for Keysight’s data center and infrastructure solutions, no one is happier than me (well, besides our customers) in this integration. Let me explain why.

Keysight is a recognized leader worldwide in the test & measurement industry for its Physical Layer 1 test solutions. Ixia tests what are typically referred to as the Networking Protocols (Layers 2/3) and what is typically called the Application Layers (4-7). Before I go into more details, this might be a good time for a quick review of the Open System Interconnect (OSI) and Transmission Control Protocol (TCP)/Internet Protocol (IP) models. They are the two most widely used models for communication networks, let’s do a quick review of them.

OSI and TCP/IP models

OSI and TCP/IP Models


As you can see, the OSI model is comprised of seven layers, whereas the TCP/IP model has four. In simple terms, regardless of the model data sent to the network flows from the top Application layer downward through each layer. Since I mentioned earlier that Keysight’s expertise is in Physical Layer 1 test, I’ll use the OSI model to explain a very simple example of how data flows through the network.

For example, when you request to browse a web page from your computer, data is sent to the Application Layer of the network. It is then passed downward through the layers, with each one performing a specific function and encapsulating the data before passing it on to the next layer. Physical Layer 1 is aptly named since it manages the point-to-point connection and physically transmits it over the network to its intended destination. There are several hardware devices that operate at Layer 1, but the most influential and the most expensive, is the transceiver.

Keysight provides the hardware and software solutions to test transceiver performance and compliance to industry standards, ensuring the very heart of every network. IHS Markit forecasts that the number of devices connected to the Internet will reach 125 billion by 2030. That is a big number, each making their demands on those transceivers. Can you imagine how many requests will be sent to and from the network with that many devices? As I wrote about in my blog last week, 400GE Innovations at OFC 2018 – Enabling 5G and IoT, we work closely with industry innovators to help them bring to market the next generation of transceivers needed to support these network demands.

Now that you understand what part of the network that Keysight tests, it is time to explain the importance of Ixia’s contribution. Ixia provides network test solutions for all the other network layers from 2-7, including validating Software Defined Networking (SDN), and Network Function Virtualization (NFV) functionality and traffic loading. Each of these topics alone are worthy of a much more detailed explanation in a future blog article, but I’ll give you a short story here.


Remember all the billions of devices I mentioned above that will connect to the network? Well, this is really pushing the limits of existing network infrastructures that have remained virtually unchanged in the last several years. Therefore, enterprises and service providers need to find new ways to design and operate their networks and are shifting to virtualized networks using SDN and NFV. Once they have made that shift, they need to make sure that data flows through their virtualized networks as they designed them to, and that they can withstand the kind of traffic that billions of devices will generate. This is what Ixia’s network test solutions are designed to do.

Together Keysight and Ixia offer the widest array of test solutions across all network layers, from Physical Layer 1 test to full network test of Layers 2-7 including SDN/NFV validation and traffic loading. It is a powerful combination to ensure actual data center infrastructure works as promised.


Learn more about Keysight’s transceiver test solutions here and Ixia’s network test solutions here.