Course Intermediate

Wireless Networks and Network Security

By the end of this course

Evaluates the coverage and interference constraints of a wireless network design
Selects VPN technologies according to the threat model
Applies network segmentation and zero trust principles

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Wireless Networks

The physics of transmission and interference, central management of access points, channel planning and cell coverage, client handovers, security generations, range-power trade-offs, and the main components of cellular architecture.

01 Physics of Wireless Transmission In wireless, the link is not binary but a graded curve: in a forty-client setup, of the 27 clients inside a thirty-meter cell only 9 run at full rate tier, 14 drop to lower tiers, and 4 cannot associate at all.
02 Access Points and Controllers Whether the decision is made at the access point or at the controller is measured: three points running on separately given budgets associate 25 clients and produce 2 false admits, a shared policy associates 23 clients and leaks zero, and the clients running at full rate rise from 5 to 9.
03 Channel Planning and Coverage At signal budget 58, 52, 46, and 40 the associated clients are 31, 23, 17, and 13; false admit is 5, 0, 0, 0 and false deny is 1, 4, 10, 14 — the configuration that zeroes out the leak leaves ten clients inside the cell out.
04 Roaming and Band Steering As the handover threshold drops from 30 to 14, false admit falls from 8 to 0 and false deny rises from 0 to 8; early handover and late handover are two ends of the same dial, and fixing one direction grows the other.
05 Wireless Security Protocols Generation selection looks like a security setting but behaves like a coverage setting: in the same forty-client set, as the generation condition rises false admit falls from 5 to 2, false deny rises from 1 to 20, and moving from mixed mode to a single generation drops 13 clients.
06 Short-Range and Wide-Area Wireless The same intent is measured across three range classes: as range grows the highest rate tier reached falls from 8 to 6, then to 2, associated clients rise from 11 to 37, and the sign of the error comes not from the class's range but from how the radius is tuned against the power budget.
07 Mobile Networks In cellular architecture the network makes the decision, not the client; as the inter-site distance is pulled in from 90 to 30, service's two-directional error falls from 5 and 1 to zero, but overlapping clients rise from 0 to 31, and the handover decision shifts from unnecessary handover to missed handover.

Network Security

Firewall types, rule writing and evaluation order, trust zones and the demilitarized zone, intrusion detection and prevention, tunneling technologies, the zero trust model, and the classes defense does not cover.

01 Firewall Types The semantics of packet-filtering, stateful, and application-aware mechanisms on the same forty flows: the unmirrored filter false-admits 6 flows and false-denies 7, the stateful mechanism zeroes both, and the application-aware mechanism — because it reads a field intent never wrote — produces only 8 false denies.
02 Access Control Lists Four rule sets on the same forty flows: the seven-rule narrow set gives 40/40 correct, the six-rule wide set false-admits 2 flows, the eight-rule misordered set also admits 2 and shadows 1 rule, and the seven-rule tightened set zeroes the leak while false-denying 2 flows.
03 Network Segmentation and DMZ The same intent is turned into a rule set across four zone graphs: in two zones, the narrowest derivation that never leaks passes nothing and false-denies 22 flows, while the wide derivation leaks 6; in four zones, 38 rules zero the deviation, and in six zones the rule count climbs to 88 while the deviation stays at zero.
04 Intrusion Detection and Prevention In a threshold-based mechanism, the two errors are tied to each other: in the network-based system, at threshold 7 false admit is 0 but false deny is 7; at threshold 9 false deny is 0 but false admit is 5. The host-based system's 8 forbidden flows, meanwhile, never show up at any threshold, because it never sees them.
05 VPN Technologies A tunnel is a routing arrangement: the tunnel selector decides which destinations it lets inside, and a flow that is not selected exits without ever seeing the boundary. Across forty flows, four selectors and two tunnel configurations measure false admit and false deny separately.
06 Zero Trust Network Model When the location criterion is stripped from the rule chain, one rule turns into an implicit allow, three rules get shadowed, and false admit climbs from zero to eighteen; when the identity criterion takes its place, rule count rises from seven to ten, and when the credential condition is added, false deny climbs from one to four.
07 Common Network Attacks When the six controls built in this course are switched on together, the number of flows on which each of four attack classes closes is counted; with the narrow selector none of them closes across all forty flows, with full tunnel only one closes, and denial of service stays open on twenty-two flows.