Wide-Area Networks (WANs) Flashcards
(139 cards)
1
Q
What does a WAN connect?
A
Distant networks
2
Q
Main WAN devices?
A
Routers and switches
3
Q
WAN supports which users?
A
Branch, remote, cloud
4
Q
WAN vs LAN range?
A
WAN = large, LAN = local
5
Q
Why use WANs?
A
Communicate across locations
6
Q
What is the Pareto Rule (1990s) in networking?
A
80% LAN, 20% WAN
7
Q
Modern WAN/LAN traffic ratio?
A
80% WAN, 20% LAN
8
Q
What reversed the 80/20 rule?
A
Cloud, VoIP, video
9
Q
Modern WAN demand?
A
High-bandwidth connections
10
Q
Main WAN connection types?
A
Fiber, cable, DSL, satellite, cellular, microwave, leased lines
11
Q
FTTH meaning?
A
Fiber to the Home
12
Q
FTTC meaning?
A
Fiber to the Curb
13
Q
FTTN meaning?
A
Fiber to the Node
14
Q
FTTB meaning?
A
Fiber to the Building
15
Q
FTTH reach?
A
Direct to home
16
Q
FTTC reach?
A
Cabinet to copper
17
Q
FTTN reach?
A
Node to copper
18
Q
FTTB reach?
A
Basement to unit
19
Q
Fastest fiber type?
A
FTTH
20
Q
FTTC trade-off?
A
Uses copper last mile
21
Q
FTTN limitation?
A
Long copper reduces speed
22
Q
FTTH use cases?
A
Streaming, gamers, home offices
23
Q
FTTB benefit?
A
Great for multi-dwelling units
24
Q
Why evaluate fiber marketing?
A
“Fiber” doesn’t always mean FTTH
25
DOCSIS stands for?
Data Over Cable Service Interface Spec
26
DOCSIS used on which network?
HFC (Hybrid Fiber-Coaxial)
27
HFC structure?
Fiber + coaxial mix
28
DOCSIS upstream freq?
5–42 MHz
29
DOCSIS downstream freq?
50–860 MHz
30
DOCSIS speeds today?
Up to 5 Gbps
31
DOCSIS speed balance?
Download >> Upload
32
Coaxial cable role in HFC?
Last mile delivery
33
DOCSIS benefits?
Fast rollout, uses TV lines
34
DOCSIS modems used where?
Homes and SOHOs
35
DSL uses which wires?
Telephone copper lines
36
Three types of DSL?
ADSL, SDSL, VDSL
37
ADSL trait?
Asymmetric speeds
38
SDSL trait?
Symmetric speeds
39
VDSL speed range?
50+ Mbps down
40
VDSL range limit?
~4000 feet
41
DSLAM function?
Aggregates DSL lines to internet
42
DSL decline reason?
Replaced by fiber and cable
43
Where ADSL still used?
Rural areas
44
VDSL vs SDSL – main use case?
VDSL = homes, SDSL = business
45
ADSL max speed?
8 Mbps down
46
DSL limitation?
Distance affects speed
47
Satellite internet for which areas?
Remote/rural
48
Main satellite types?
GEO and LEO
49
GEO satellite altitude?
~22,000 miles
50
LEO satellite altitude?
~340 miles
51
GEO latency?
~500 ms
52
LEO latency?
25–35 ms
53
Dish requirements?
Clear line-of-sight
54
Satellite cons?
Latency, cost, weather
55
Starlink is what type?
LEO satellite
56
Starlink speed & latency?
Fast, low-latency
57
Satellite modem connects to?
Coax to dish
58
Example GEO provider?
HughesNet
59
Starlink coverage method?
Thousands of small satellites
60
Common WAN cellular devices?
Phones, tablets, hotspots
61
First gen (1G) used?
Analog voice
62
2G introduced what?
SMS, digital
63
3G added?
Voice + data
64
4G introduced?
LTE, 1 Gbps
65
5G supports up to?
10 Gbps
66
5G low-band trait?
Long range
67
5G mid-band trait?
Balanced speed/range
68
5G high-band trait?
Very fast, short range
69
GSM key trait?
SIM-based
70
CDMA key trait?
No SIM (pre-3G)
71
Tethering meaning?
Share mobile data
72
Hotspot role?
Cellular to Wi-Fi bridge
73
Fixed wireless uses what?
Stationary LTE/5G modem
74
Microwave WAN uses?
Point-to-point, line-of-sight
75
Frequency range of microwave?
300 MHz–300 GHz
76
Standard for fixed wireless?
IEEE 802.16 (WiMAX)
77
Max microwave distance?
~40 miles
78
LOS stands for?
Line-of-sight
79
Microwave common locations?
Campuses, business parks
80
LOS obstructions include?
Trees, terrain, buildings
81
Why is WiMAX different from Wi-Fi?
Longer range, fixed use
82
Microwave vs cellular mobility?
Microwave = fixed
83
Why is microwave declining?
5G and cellular expansion
84
What is a leased line?
Dedicated WAN link
85
Leased line bandwidth type?
Symmetric
86
Key leased line use cases?
Enterprise, branches
87
Cost of leased lines?
High
88
SLA benefit?
Guaranteed uptime
89
Uptime guarantee typical?
99.9%+
90
Leased line bandwidth scale?
2 Mbps to 10+ Gbps
91
Data isolation benefit?
Doesn’t use public internet
92
Ideal leased line users?
Banks, hospitals, legal
93
Leased line install needs?
Contract and provider access
94
MPLS is what type of tech?
Label-switching
95
MPLS replaces what?
IP header-based routing
96
Label assigned by?
Ingress router
97
Label removed by?
Egress router
98
Benefit of labels?
Faster forwarding
99
MPLS supports what?
QoS, traffic engineering
100
ISP use of MPLS?
Backbone routing
101
MPLS supports which protocols?
Ethernet, ATM, Frame Relay
102
MPLS impact on users?
Faster, more reliable connections
103
Common home WAN modem?
Cable modem
104
Fiber modem role?
Converts fiber to Ethernet
105
Satellite modem connects to?
Roof dish
106
Cellular device output?
USB or Wi-Fi
107
Common WAN device output port?
RJ-45 Ethernet
108
Most common modem in remote areas?
Satellite
109
Hotspots use which tech?
Cellular
110
3 key performance metrics?
Latency, bandwidth, jitter
111
Latency measures?
Round-trip time
112
Jitter definition?
Variation in delay
113
Throughput vs bandwidth?
Actual vs. theoretical
114
High jitter affects?
VoIP, video
115
Tool to check latency?
ping
116
Tool to check speed?
speedtest.net
117
Reason for slow throughput?
Wi-Fi, congestion
118
QoS used to?
Prioritize traffic
119
Metric most critical for VoIP?
Jitter
120
Interface definition?
Port on network device
121
"Line protocol down" means?
Logical connection is off
122
Ethernet MTU size?
1500 bytes
123
Bandwidth shown as?
kbps (e.g., 100000 kbps)
124
Reliability 255/255 means?
No packet loss
125
TXload/RXload show?
Traffic buffer usage
126
ARP timeout default?
4 hours
127
Input queue holds?
Incoming packets
128
Output queue holds?
Packets ready to send
129
CRC errors mean?
Damaged packet
130
Frame < 64 bytes?
Runt
131
Frame > 1518 bytes?
Giant
132
Overrun error?
Buffer can't keep up
133
Watchdog timer error?
Oversized packet timeout
134
Collision in full duplex?
Misconfigured port
135
Babbles mean?
Oversized outbound frame
136
Late collision indicates?
Detected too late during send
137
Lost carrier means?
Signal dropped during send
138
Half duplex + collisions means?
Duplex mismatch
139
Tool for interface diagnostics?
Show interface (Cisco)
