At which OSI layer do switches operate to forward frames based on MAC addresses?
Answer: B
Switches operate at Layer 2 (Data Link Layer) and use MAC address tables to forward frames to appropriate ports within a LAN.
Q.42Easy
Which of the following protocols operates at the Transport Layer (Layer 4) of the OSI model?
Answer: B
TCP and UDP are Transport Layer protocols that manage end-to-end communication, reliability, and port-based services.
Q.43Easy
What is the primary function of the Presentation Layer (Layer 6) in the OSI model?
Answer: B
Layer 6 handles data formatting, encryption, compression, and conversion between different character sets and formats for application compatibility.
Q.44Easy
In the context of the OSI model, which layer is responsible for establishing, maintaining, and terminating connections?
Answer: B
The Session Layer (Layer 5) manages dialog control, session establishment, maintenance, and termination between applications.
Q.45Medium
An organization implements Quality of Service (QoS) policies for video streaming. At which OSI layer would bandwidth prioritization rules primarily be enforced?
Answer: C
QoS policies are typically enforced at the Transport Layer using protocols like DSCP and traffic shaping techniques to prioritize critical traffic.
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Q.46Medium
A network administrator notices that devices can connect physically but cannot communicate. After checking cables and signals, the issue remains. Which layers should be investigated?
Answer: C
Physical connectivity (Layer 1) works, so the issue is likely at Layer 2 (MAC addressing/switching) or Layer 3 (IP routing/addressing).
Q.47Medium
When a web browser displays encrypted HTTPS content correctly on the user's screen, which layers have successfully completed their functions in the correct sequence?
Answer: B
All seven layers must function correctly: physical transmission (1), framing (2), routing (3), TCP connection (4), session (5), decryption (6), and HTML rendering (7).
Q.48Medium
Which statement correctly describes the relationship between protocols and OSI layers?
Answer: B
Protocols like TCP/IP stack operate across multiple layers; HTTP spans layers 6-7, while TCP operates at layer 4.
Q.49Medium
A company deploys a VPN solution. At which OSI layer does the VPN primarily encrypt data before transmission?
Answer: C
VPNs perform encryption/decryption at the Presentation Layer, though some VPN implementations also work at Layer 3 for IP-level protection.
Q.50Medium
During a network troubleshooting session, a technician finds that DNS resolution fails while DHCP assignment succeeds. Which layers are functioning and which is failing?
Answer: C
DHCP (Layer 4) works, so Layers 1-4 are functional. DNS resolution failure indicates an issue at the Application Layer (Layer 7) or network configuration.
Q.51Medium
A firewall is configured to block traffic on specific ports. At which minimum OSI layer must the firewall operate to enforce this rule?
Answer: B
Port-based filtering requires inspection at the Transport Layer (Layer 4) where ports (TCP/UDP) are defined and identified.
Q.52Medium
In a complex network architecture, data flows through multiple devices: modem → switch → router → firewall → server. Which device primarily operates at Layer 3?
Answer: C
Routers operate at Layer 3 (Network Layer) to route packets based on IP addresses, while other devices operate at lower layers.
Q.53Hard
A network protocol analyzer shows that frames are arriving at a computer but being dropped at the Network Layer. What is the most likely cause?
Answer: B
If frames arrive at Layer 2 but are dropped at Layer 3, the issue involves IP addressing, routing tables, or network configuration at the Network Layer.
Q.54Hard
An organization implements network segmentation using VLANs. At which OSI layer does VLAN tagging primarily operate, and which layer processes these tags?
Answer: B
VLAN tagging operates at Layer 2 (Data Link Layer) using 802.1Q tags, and switches process these tags at Layer 2 to isolate traffic.
Q.55Hard
Consider a scenario where SSL/TLS encryption is implemented. At which OSI layer is the encryption applied, and through which layer does encrypted traffic pass without modification?
Answer: C
SSL/TLS operates at Layer 7 (Application Layer), encrypting application data. Lower layers (1-6) transparently carry encrypted data without understanding its content.
Q.56Hard
In a load-balancing scenario, traffic is distributed across multiple servers based on source IP addresses. At which OSI layer does this decision-making primarily occur?
Answer: B
Load balancing based on IP addresses operates at the Network Layer (Layer 3) for Layer 3 load balancing, though advanced load balancers work at higher layers.
Q.57Hard
A network architect must design a system where two applications on the same computer communicate without leaving the system. Which OSI layers are bypassed in this internal communication?
Answer: C
Internal inter-process communication (IPC) bypasses physical transmission and network routing, skipping Layers 1-3, and operates at Layers 4-7.
Q.58Hard
When implementing network monitoring with packet sniffing at multiple layers, which combination accurately represents the data structures captured at each layer?
Answer: A
Layer 2 creates Frames with MAC addresses, Layer 3 creates Packets with IP addresses, and Layer 4 creates Segments (TCP) or Datagrams (UDP).
Q.59Hard
A security incident reveals that an attacker exploited a vulnerability at Layer 5 (Session Layer). Which attack vector most likely matches this layer?
Answer: B
Session hijacking targets the Session Layer (Layer 5) by intercepting and taking control of established sessions between applications.
Q.60Easy
Which layer of the OSI model is responsible for routing and logical addressing?
Answer: A
The Network Layer (Layer 3) handles routing decisions and logical addressing using IP addresses. It determines the best path for data packets to travel across networks.
