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GK One-Line Question & Answer

15541+ short questions with short answers, covering every category and sub-category on the site — no long articles to scroll through. Good for a fast recap before an exam, or a few minutes of daily practice.

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Computer Networks → HTTP and HTTPS 1

WebSocket upgrade uses which HTTP method
GET with Upgrade header
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Computer Networks → Introduction to Computer Networks 36

SSE (Server-Sent Events) is
One-way server-to-client streaming
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AMQP exchange types include
Direct fanout topic and headers
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Kafka is
Distributed event streaming platform
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RabbitMQ implements
AMQP protocol
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OVN in OpenStack provides
Open Virtual Network overlay
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Geneve encapsulation provides
Variable metadata for extensible network virtualization
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NVGRE competes with
VXLAN
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ACI EPG stands for
End Point Group
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ACI contract defines
Communication rules between EPGs
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NSX distributed firewall is at
Each hypervisor kernel for VM-level segmentation
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VMware NSX-T supports
Multiple hypervisors KVM ESXi and containers
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AWS transit gateway acts as
Hub connecting multiple VPCs and on-premises
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AWS PrivateLink avoids traffic going through
Public internet
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Network tap is
Passive hardware splitter for non-intrusive monitoring
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Wireshark capture filter is applied
Before capture at driver level (BPF)
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Wireshark display filter is applied
After capture to filter displayed packets
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tcpdump -i any captures on
All interfaces
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nmap -sS performs
TCP SYN half-open scan
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nmap -sU performs
UDP scan
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nmap -O attempts
OS fingerprinting
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iperf3 -s starts iperf in
Server mode
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MTR combines
Ping and traceroute for continuous path analysis
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Bandwidth-delay product equals
Bandwidth x Delay (bits in flight)
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Little Law in queuing N equals
Lambda x W
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M/M/1 queue as utilization approaches 1
Queue length approaches infinity
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Goodput excludes
Overhead retransmissions and protocol headers
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Shannon limit for fiber is approximately
Around 100 Tbps per fiber
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CWDM supports fewer wavelengths than DWDM because
Wider channel spacing 20 nm vs 0.8 nm
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DP-QPSK encodes per symbol
8 bits (4 per polarization x 2 polarizations)
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OTN G.709 wraps SONET/SDH with
Enhanced OAM FEC and mapping
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Flex-grid DWDM uses
Variable channel widths for spectral efficiency
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SDM uses multiple fiber
Cores or modes for more capacity
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BGP NEXT_HOP attribute contains
IP address of next router to reach destination
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BGP ORIGIN i means route was
Learned from interior IGP
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BGP ORIGIN e means route was
Learned from exterior EGP protocol
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BGP ORIGIN ? means route was
Redistributed (incomplete origin)
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Computer Networks → Types of Networks 2

VXLAN VNI 0 is
Not valid - reserved
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SPAN vs tap key difference is
SPAN may drop packets; tap always captures all traffic
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Computer Networks → Routing Algorithms 1

OSPF Type 7 LSA is converted to Type 5 at
ABR when leaving NSSA
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