TCP/IP Networking Fundamentals for Sysadmins Networking 101 Back to Basics Aaron Staines NETWORK/SYSTEM ENGINEER | CCISO Module Overview What Is the OSI Model (Overview) Physical Layer of OSI Model Data Layer of OSI Model Network Layer of OSI Model Module Overview Transport Layer of OSI Model Session Layer of OSI Model Presentation Layer of OSI Model Application Layer of OSI Model OSI Model Overview OSI Model Overview Layer 7 Application Layer 6 Presentation Layer 5 Session Layer 4 Transport Layer 3 Network Layer 2 Data Layer 1 Physical What Is the Physical Layer of the OSI Model What Is the Physical Layer of the OSI Model Physical Issues – Cables/Equipment Electrical Current as Data Old School Telegraph Hub – Don’t Use What Is the Physical Layer of the OSI Model What Is the Data Layer of the OSI Model What Is the Data Layer of the OSI Model Switches Live Here Generally Data - Frames Uses MAC Addresses MAC Table – Maps MAC to Port What Is the Data Layer of the OSI Model ARP – IP to MAC Address What Is the Data Layer of the OSI Model 192.168.1.4 192.168.1.2 192.168.1.1 192.168.1.3 What Is the Network Layer of the OSI Model What Is the Network Layer of the OSI Model Equipment – Routers / Firewalls / Switches Firewalls Can Operate in Layers 3 – 7 Layer 3 Switch – Limited Layer 3 Layer 3 Switch – Cost Savings What Is the Network Layer of the OSI Model Other Equipment Types Exist IP Addressing Lives Here Layer 3 Has Protocols What Is the Transport Layer of the OSI Model What Is the Transport Layer of the OSI Model Responsible – Transportation / Ports Reliable Transportation 2 Port Types – TCP / UDP What Is the Session Layer of the OSI Model What Is the Session Layer of the OSI Model Old School Switchboard Operators Establish The Session Maintain The Session Reconnect Session What Is the Session Layer of the OSI Model Terminate Session Session Termination – Not Always By Choice 2 Year Old – Destroy Sessions What Is the Presentation Layer of the OSI Model What Is the Presentation Layer of the OSI Model 3 Critical Functions 1. Makes Code Useable for Application Layer 2. Compresses Data – Think Zipping a File 3. Encryption – Obfuscation of Data What Is the Application Layer of the OSI Model What Is the Application Layer of the OSI Model Where Users See Issues Start at Layer 1 Work through the Layers until Resolution Module Review OSI Cake Acronym – All People Seem To Need Data Processing Physical Layer – Current / Don’t Use Hubs Data Layer – Switches / MAC Addresses Module Review Network Layer – Routers / Firewalls / IP Transport Layer – Virtual Train / Ports Session Layer – Modern Day Switchboard Presentation Layer – Usable Data / Encrypt Application Layer – Users Notice Issues Here