About This Domain
Domain 1 — Network Fundamentals — accounts for 20% of the CCNA certification exam. This domain evaluates your understanding of compare and contrast osi and tcp/ip models, describe characteristics of network topology architectures (two-tier, three-tier, spine-leaf, wan, soho, on-premises, cloud), compare physical interface and cabling types (single-mode fiber, multi-mode fiber, copper, poe), and related concepts. Domain 1 covers the role and function of network components, network topology architectures, physical interfaces, cabling types, and TCP/IP and OSI model concepts. To pass this section you need practical knowledge of how these services and patterns work together in real-world architectures.
What You'll Be Tested On
- Compare and contrast OSI and TCP/IP models
- Describe characteristics of network topology architectures (two-tier, three-tier, spine-leaf, WAN, SOHO, on-premises, cloud)
- Compare physical interface and cabling types (single-mode fiber, multi-mode fiber, copper, PoE)
- Identify interface and cable issues (collisions, errors, duplex, speed)
- Compare TCP and UDP
- Configure and verify IPv4 addressing and subnetting
Key Cisco Technologies in This Domain
Study Strategy for Domain 1
While 20% might seem like a smaller portion of the exam, every point counts toward the passing score. Focus on understanding core concepts and common exam scenarios for this domain.
Exam Tips for Domain 1
Know the 7 OSI layers and which protocols operate at each layer.
Understand the TCP three-way handshake (SYN, SYN-ACK, ACK).
Be comfortable with subnetting calculations — they appear frequently.
Know the difference between collision domains and broadcast domains.
Frequently Asked Questions
How many questions on the CCNA exam come from Domain 1?
Domain 1 (Network Fundamentals) makes up 20% of the CCNA exam. The exam has 65 scored questions, so approximately 13 questions will come from this domain.
What services should I focus on for Domain 1?
The key services for this domain include Network Fundamentals, IP Addressing, Switching, WAN. Make sure you understand how each service works, its use cases, and how they integrate with one another.
How should I prepare for Network Fundamentals questions?
Start by reviewing the key topics listed above, then practice with domain-specific questions. Focus on understanding real-world scenarios rather than memorizing facts.
What's the best order to study the CCNA domains?
Many candidates start with the highest-weighted domains first. For the CCNA exam, the domains in order of weight are: Network Fundamentals (20%), Network Access (20%), IP Connectivity (25%), IP Services (10%), Security Fundamentals (15%), Automation and Programmability (10%).
Practice Domain 1 Questions
Test your knowledge of Network Fundamentals with practice questions from our CCNA question bank.
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