DevOps Networking Syllabus

Networking syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Networking in DevOps, not a summary of it.

1. 1

   Network Fundamentals

   3 topics

   • OSI Model
     • Physical Layer
     • Data Link Layer
     • Network Layer
     • Transport Layer
     • Session Layer
     • Presentation Layer
     • Application Layer
   • TCP/IP Model
     • Network Interface Layer
     • Internet Layer
     • Transport Layer
     • Application Layer
   • IP Addressing
     • IPv4 and IPv6 addressing
     • Subnetting
     • CIDR notation
2. 2

   Networking Protocols

   7 topics

   • TCP/UDP
     • Differences between TCP and UDP
     • Common ports and services
   • HTTP/HTTPS
     • Basics of web communication
     • HTTP methods
   • DNS (Domain Name System)
     • DNS Basics
     • DNS records
     • DNS Tools
   • Firewalls
     • Firewall Basics
     • Firewall Configuration
   • Load Balancers
     • Basics of Load Balancing
     • Types of load balancing
     • Tools
   • Virtual Private Networks (VPNs)
     • VPN Basics
     • Tools
   • Network Security
     • Security Basics
     • Tools

Networking flashcards for DevOps

21 of 51 cards from the Networking deck — real questions with worked answers.

1. What are the seven layers of the OSI model, in order from Layer 1 to Layer 7?

   Layer 1 Physical, Layer 2 Data Link, Layer 3 Network, Layer 4 Transport, Layer 5 Session, Layer 6 Presentation, Layer 7 Application. A common mnemonic is "Please Do Not Throw Sausage Pizza Away."

2. At which OSI layer do routers and IP addressing operate, and what is that layer's primary responsibility?

   The Network layer (Layer 3). It handles logical addressing (IP) and routing of packets between different networks.

3. Which OSI layer do switches and MAC addresses operate at, and what is its protocol data unit (PDU)?

   The Data Link layer (Layer 2). Its PDU is the frame, and it uses MAC (hardware) addresses for delivery within a local network segment.

4. Name the protocol data unit (PDU) used at the Transport, Network, and Data Link layers of the OSI model.

   Transport layer: segment (TCP) or datagram (UDP). Network layer: packet. Data Link layer: frame. (Physical layer: bits.)

5. What is the function of the OSI Presentation layer (Layer 6)?

   It handles data translation, encryption/decryption, and compression, presenting data in a format the Application layer can use (e.g., SSL/TLS, character encoding, JPEG/ASCII).

6. How many layers does the TCP/IP model have, and what are they?

   Four layers: Application, Transport, Internet, and Network Access (Link). Some descriptions use a five-layer variant that splits Network Access into Data Link and Physical.

7. How do the layers of the TCP/IP model map to the OSI model?

   TCP/IP Application = OSI Application + Presentation + Session; TCP/IP Transport = OSI Transport; TCP/IP Internet = OSI Network; TCP/IP Network Access = OSI Data Link + Physical.

8. What is encapsulation in the context of network models?

   The process by which each layer adds its own header (and sometimes trailer) to the data received from the layer above as it travels down the stack; the receiving host reverses this with decapsulation.

9. How many bits are in an IPv4 address and an IPv6 address?

   IPv4 uses $32$ bits (about $4.3 \times 10^{9}$ addresses); IPv6 uses $128$ bits (about $3.4 \times 10^{38}$ addresses).

10. What is the total number of possible IPv4 addresses, expressed as a power of two?

    $2^{32} = 4{,}294{,}967{,}296$ addresses.

11. List the default (classful) address ranges for Class A, B, and C IPv4 networks by first octet.

    Class A: $1$–$126$; Class B: $128$–$191$; Class C: $192$–$223$. (Class D $224$–$239$ is multicast; Class E $240$–$255$ is experimental.)

12. What are the three private IPv4 address ranges defined by RFC 1918?

    $10.0.0.0/8$, $172.16.0.0/12$, and $192.168.0.0/16$.

13. For a subnet with prefix length $/n$, what formula gives the number of usable host addresses?

    $2^{(32 - n)} - 2$, subtracting the network address and the broadcast address.

14. How many usable hosts are in a $/24$ subnet?

    $2^{(32-24)} - 2 = 2^{8} - 2 = 254$ usable hosts.

15. What is the subnet mask for a $/26$ network in dotted-decimal notation, and how many usable hosts does it provide?

    $255.255.255.192$, providing $2^{6} - 2 = 62$ usable hosts.

16. What does CIDR stand for, and what does the number after the slash (e.g., $/24$) represent?

    Classless Inter-Domain Routing. The number is the prefix length: the count of leading bits used for the network portion of the address.

17. What is the purpose of NAT (Network Address Translation)?

    It maps multiple private IP addresses to one or more public IP addresses, conserving public IPv4 space and hiding internal addresses behind a router/gateway.

18. What is the loopback address in IPv4 and in IPv6?

    IPv4 loopback is $127.0.0.1$ (range $127.0.0.0/8$); IPv6 loopback is $::1$.

19. Compare TCP and UDP on connection setup, reliability, and ordering.

    TCP is connection-oriented, reliable, and delivers data in order (with acknowledgments and retransmission). UDP is connectionless, unreliable (best-effort), and does not guarantee ordering.

20. Describe the steps of the TCP three-way handshake.

    1) Client sends SYN; 2) Server replies SYN-ACK; 3) Client sends ACK. The connection is then established.

21. Which transport protocol is typically preferred for real-time applications like video streaming, VoIP, and online gaming, and why?

    UDP, because its low overhead and lack of retransmission/ordering give lower latency; occasional lost packets are preferable to delay in real-time media.

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