Quick Revision

GK One-Line Question & Answer

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Computer Fundamentals → Introduction to Computer 40

VLAN hopping attack techniques include?
Switch spoofing and double tagging (802.1Q)
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Port security on switches limits?
Number of MAC addresses allowed per port
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MAC flooding attack aims to?
Fill the CAM table forcing the switch to flood all frames like a hub
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Private VLAN (PVLAN) provides?
Layer 2 isolation between ports in the same VLAN (promiscuous, isolated, community)
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Which QoS marking is used at Layer 2?
CoS (Class of Service) in 802.1Q tag
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DSCP in QoS marks traffic at?
Layer 3 — 6 bits in IP header ToS/DS field
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ECN (Explicit Congestion Notification) allows?
Routers to signal congestion without packet drop to TCP endpoints
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Traffic shaping vs policing: shaping?
Buffers/delays excess traffic to conform to rate — smoother output
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DiffServ QoS model provides?
Scalable per-class service differentiation across the network
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IntServ (Integrated Services) QoS uses?
Per-flow resource reservation using RSVP
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RSVP (Resource Reservation Protocol) is used for?
Reserving network resources for specific flows (IntServ QoS)
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MPLS label stack supports?
Multiple labels (label stacking) for nested tunnels
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MPLS TE (Traffic Engineering) allows?
Explicit path control different from IGP shortest path
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Segment Routing (SR-MPLS, SRv6) advantage over MPLS TE?
Source-based path encoding eliminates per-router state and RSVP signaling
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SRv6 encodes path information using?
IPv6 extension headers (Segment Routing Header)
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EVPN (Ethernet VPN) is used for?
Providing Layer 2 VPN services over MPLS/VXLAN using BGP control plane
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VXLAN (Virtual Extensible LAN) extends VLANs by?
Encapsulating Layer 2 frames in UDP/IP, supporting 16M virtual networks
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GENEVE (Generic Network Virtualization Encapsulation) improves on VXLAN by?
Extensible metadata in header for more flexible network virtualization
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BGP EVPN uses which address families?
L2VPN EVPN (AFI 25, SAFI 70) for MAC/IP distribution
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Which protocol provides underlay in modern data center fabrics?
BGP with ECMP (Equal Cost Multi-Path)
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Spine-Leaf data center architecture provides?
Consistent low-latency any-to-any connectivity with 2 hops maximum
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ECMP (Equal Cost Multi-Path) allows?
Traffic load balancing across multiple equal-cost paths simultaneously
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Which hashing is used for ECMP flow distribution?
5-tuple hash (src IP, dst IP, src port, dst port, protocol)
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TRILL (Transparent Interconnection of Lots of Links) was designed to?
Enable optimal routing between switches (IS-IS based)
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SPB (Shortest Path Bridging, 802.1aq) uses?
IS-IS for computing shortest paths in Ethernet networks
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BFD (Bidirectional Forwarding Detection) provides?
Fast failure detection (sub-second) independent of routing protocol
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YANG data models are used in?
Network automation with NETCONF/RESTCONF for structured device configuration
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NETCONF protocol uses?
XML over SSH for network device configuration and management
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RESTCONF is to NETCONF as?
REST API to NETCONF — uses HTTP/HTTPS with JSON/XML for YANG-modeled data
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gNMI (gRPC Network Management Interface) uses?
gRPC/Protocol Buffers for streaming telemetry and device management
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Streaming telemetry vs SNMP polling: streaming?
Devices push data continuously — lower latency, higher frequency
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Which protocol provides NAT traversal for VoIP?
STUN (Session Traversal Utilities for NAT)
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TURN (Traversal Using Relays around NAT) is used when?
STUN fails — relays media through TURN server for symmetric NAT
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ICE (Interactive Connectivity Establishment) in WebRTC?
Systematically tries STUN/TURN/direct paths to find best connection
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SIP (Session Initiation Protocol) is used for?
Establishing, modifying, terminating multimedia sessions (VoIP)
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RTP (Real-time Transport Protocol) carries?
Media streams (audio/video) with timing and sequence information
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RTCP provides?
Quality statistics and control for RTP streams
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Jitter in network quality refers to?
Variation in packet arrival delay — problematic for real-time audio/video
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Jitter buffer compensates for jitter by?
Buffering received packets and playing them at consistent intervals
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Which codec is used in WebRTC for audio?
Opus (with fallback to G.711)
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