121. What is the primary benefit of SD-WAN compared to traditional WAN?
- a) Dynamic path selection based on application needs
- b) Higher bandwidth circuits
- c) Proprietary hardware requirements
- d) Manual traffic engineering
Answer: A - SD-WAN uses policies to automatically route traffic over optimal paths (MPLS, LTE, broadband).
122. Which component virtualizes network functions in NFV architecture?
- a) VNF (Virtual Network Function)
- b) Hypervisor
- c) SDN Controller
- d) Bare-metal switch
Answer: A - VNFs (e.g., virtual firewalls, routers) run as software on commercial off-the-shelf servers.
123. What is the purpose of OTN (Optical Transport Network)?
- a) High-capacity transport of multiple protocols over fiber
- b) Wireless last-mile connectivity
- c) IoT device management
- d) DNS resolution acceleration
Answer: A - OTN (ITU-T G.709) provides error correction and multiplexing for DWDM systems (100Gbps+).
124. Which blockchain feature enhances network security transparency?
- a) Immutable ledger
- b) Proof of Work
- c) Smart contracts
- d) Tokenization
Answer: A - Blockchain's append-only ledger provides tamper-evident records for security audits.
125. What does DWDM stand for in optical networking?
- a) Dense Wavelength Division Multiplexing
- b) Digital Waveform Data Modulation
- c) Dual-Wire Data Management
- d) Dynamic Wideband Data Multiplexer
Answer: A - DWDM combines 80+ optical channels (λ) on a single fiber (C-band: 1530-1565nm).
126. Which protocol enables virtual machine mobility across data centers?
- a) VXLAN
- b) VLAN
- c) STP
- d) OSPF
Answer: A - VXLAN's 24-bit VNI allows Layer 2 extension over Layer 3 networks (RFC 7348).
127. What is the primary use of a smart contract in blockchain networking?
- a) Automatically executing agreements when conditions are met
- b) Encrypting all network traffic
- c) Replacing TCP/IP protocols
- d) Managing optical transceivers
Answer: A - Smart contracts enable trustless automation (e.g., IoT micropayments, SLA verification).
128. Which technology separates underlay and overlay networks?
- a) SDN (Software-Defined Networking)
- b) MPLS
- c) BGP
- d) ARP
Answer: A - SDN decouples control plane (overlay) from data plane (underlay) via OpenFlow.
129. What is the purpose of FEC (Forward Error Correction) in optical networks?
- a) To detect and correct bit errors without retransmission
- b) To encrypt data in transit
- c) To prioritize latency-sensitive traffic
- d) To convert electrical signals to optical
Answer: A - FEC (e.g., Reed-Solomon) maintains signal integrity over long-haul fiber links.
130. Which blockchain consensus mechanism is most energy-efficient?
- a) Proof of Stake (PoS)
- b) Proof of Work (PoW)
- c) Proof of Authority (PoA)
- d) Proof of History (PoH)
Answer: A - PoS selects validators based on coin ownership vs. PoW's computational puzzles.
131. What does CORD stand for in network virtualization?
- a) Central Office Re-architected as a Datacenter
- b) Cloud-Optimized Routing Domain
- c) Core Optical Repeater Device
- d) Cryptographic On-demand Routing
Answer: A - CORD combines NFV, SDN, and cloud economics for telecom central offices.
132. Which optical component amplifies signals without O-E-O conversion?
- a) EDFA (Erbium-Doped Fiber Amplifier)
- b) Transponder
- c) Mux/Demux
- d) Regenerator
Answer: A - EDFAs boost optical signals directly in the 1550nm window (C-band).
133. How does blockchain improve IoT device identity management?
- a) Decentralized authentication via digital fingerprints
- b) Faster DNS resolution
- c) Lower power consumption
- d) Increased wireless range
Answer: A - Blockchain provides tamper-proof device identities without central authorities.
134. Which protocol manages virtual network service chaining?
- a) NSH (Network Service Header)
- b) VLAN
- c) BGP
- d) OSPF
Answer: A - NSH (RFC 8300) defines packet paths through VNF sequences (firewall → IDS → LB).
135. What is the purpose of a ROADM in optical networks?
- a) Reconfigurable wavelength routing
- b) Optical encryption
- c) Signal regeneration
- d) Packet switching
Answer: A - ROADMs (Reconfigurable Optical Add-Drop Multiplexers) dynamically manage λ channels.
136. Which NFV component manages lifecycle operations of VNFs?
- a) MANO (Management and Orchestration)
- b) VIM (Virtualized Infrastructure Manager)
- c) Hypervisor
- d) SDN Controller
Answer: A - MANO (ETSI standard) handles VNF deployment, scaling, and termination.
137. What does P4 programming language enable in SDN?
- a) Protocol-independent packet processing
- b) Optical signal modulation
- c) Blockchain smart contracts
- d) Quantum encryption
Answer: A - P4 programs switches to handle custom headers and forwarding logic.
138. Which blockchain network is optimized for IoT micropayments?
- a) IOTA
- b) Bitcoin
- c) Ethereum
- d) Hyperledger
Answer: A - IOTA uses Tangle (DAG) instead of blockchain for feeless nano-transactions.
139. What is the primary advantage of Coherent Optics?
- a) Higher capacity over existing fiber
- b) Lower latency than DWDM
- c) Wireless backhaul support
- d) Quantum key distribution
Answer: A - Coherent detection (DP-QPSK, 16QAM) enables 400Gbps+ per wavelength.
140. Which technology virtualizes the radio access network (RAN)?
- a) vRAN (Virtualized RAN)
- b) MPLS
- c) IPsec
- d) BGP
Answer: A - vRAN separates BBU (Baseband Unit) functions into software running on COTS servers.