LMTV LIVE | WiFi Analytics (with John Kerber, CEO of Who's On My WiFi)
How TCP Works - The Handshake (by Chris Greer)

Network Troubleshooting Through the OSI Model (by Melany Joy Beck)

Network Troubleshooting Through the OSI Model

When it comes to network troubleshooting, working through the Open Systems Interconnection (OSI) model is a straightforward process. With the exception of Layer 1, each layer of the OSI model relies on the next lower layer to provide services as specified. Requests drop down and are completed, as every layer interacts with the next layer, both above and below. When dealing with different layers, understanding how each delivers data and functions impacts how you will troubleshoot.

FREE!

Viavi guide to enterprise protocols poster – Get yours today. 

Viavi free osi

Layer Highlights and Functions - A complete view from Layer 1 through Layer 7!

Read on to see each layer overview and more free links below - 

 

Physical Layer

  • If it can blind or shock you, think Physical Layer
  • Defines physical characteristics of cables and connectors
  • Provides the interface between network and network devices
  • Describes the electrical, light, or radio data stream signaling

Data Link Layer

  • Converts signals into bits which become the packet data that everyone wants
  • Performs error detection and correction of the data streams
  • Manages flow and link control between the physical signaling and network
  • Constructs and synchronizes data frame packets

Network Layer

  • Logical addressing, routing, and packet generation
  • Carries out congestion control and error handling
  • Route monitoring and message forwarding

The root cause of application anomalies don’t stop at Layer 3 of the OSI model. In fact, some of the most difficult to diagnose service issues are rooted in, or manifest themselves at the Transport Layer (Layer 4) or higher. Since the Transport layer is responsible for building and maintaining sessions between devices, it serves to connect the lower layers (1-3) to the higher layers (5-7). It can also be the point of referred pain, when the real source of the problem lies elsewhere.

Transport Layer

  • End-to-end connection and connectionless data delivery management
  • Ensures reliable packet delivery caused by network congestion & errors
  • Congestion avoidance and data transmission flow control

Session Layer

  • Establishes, manages, and terminates application connections
  • Manages data transfer permissions and records upper layer errors

Presentation Layer

  • Application, system, and network independent data formatting
  • Data conversion, compression, encryption, and decryption

Application Layer

  • Supports application and end-user processes
  • Offers application services
  • User identification, authentication, and privacy

The Viavi Guide to Enterprise Protocols poster provides you with a comprehensive visual perspective into key enterprise protocols and their relationships across the entire OSI model from the physical to application layer.

Get a complimentary copy of the protocol poster in digital format – or by mail

For faster troubleshooting at any layer, begin with a solid understanding of how the issue affects the user. Using the right performance management tools along with the OSI model, you’ll be able to more effectively apply analysis and identify root cause.

For more details on troubleshooting at every layer of the OSI model, download Troubleshooting Layers 1-3 of the OSI Model and Troubleshooting Layers 4-7 of the OSI Model white papers featuring network pros Tony Fortunato and Mike Motta today.

Author – Melany Joy Beck is a Solutions Marketing Manager at Viavi. With both a hardware troubleshooting and technical writing background, Melany is responsible for producing white papers and case studies related to network performance monitoring and diagnostics, as well as test and certification for the enterprise.

Headquartered in Milpitas, CA, Viavi provides solutions for 360-degree visibility across physical, virtual, and cloud environments from physical media to the application layer.

BeckAuthor – Melany Joy Beck is a Solutions Marketing Manager at Viavi. With both a hardware troubleshooting and technical writing background, Melany is responsible for producing white papers and case studies related to network performance monitoring and diagnostics, as well as test and certification for the enterprise. 

Headquartered in Milpitas, CA, Viavi ( Originally Network Instruments) provides solutions for 360-degree visibility across physical, virtual, and cloud environments from physical media to the application layer. Learn more about how Viavi can help your organization to ensure optimal network performance.

Comments