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--- networking:wireless_topic:wi-fi_standards:wi-fi_4-8 [2026/02/02 18:19] – aperez
+++ networking:wireless_topic:wi-fi_standards:wi-fi_4-8 [2026/02/03 16:24] (current) – [Best practics IAP Aruba Networks] aperez
@@ Line 178: / Line 178: @@
 {{ :networking:wireless_topic:wi-fi_6:mcs-table-he-ofdm-3ss_orig.png?1000 |}}
+----
+----
 {{ :networking:wireless_topic:wi-fi_standards:noise_floor.png?600 |}}
+{{ :networking:wireless_topic:wi-fi_standards:ap.png?600 |}}
+<code bash>
+SNR = RSSI – Noise
+SNR = (–75) – (–81)
+SNR = 6 dB
+</code>
+====== Wi-Fi RF Metrics Guide (RSSI, Noise, SNR) ======
+===== What Do These Acronyms Mean? =====
+^ Acronym ^ Full Name ^ What It Measures ^
+| RSSI | Received Signal Strength Indicator | How strong the Wi-Fi signal from the AP is when it reaches the client |
+| Noise | Noise Floor | The amount of background radio interference on the channel |
+| SNR | Signal-to-Noise Ratio | How much stronger the signal is compared to the noise (true link quality) |
+----
+===== RSSI — Received Signal Strength Indicator =====
+^ RSSI (dBm) ^ Signal Quality ^ Technical Meaning ^ User Experience Impact ^
+| -30 to -50 | Excellent | Very strong signal, client is close to AP | Maximum speed and stability |
+| -51 to -60 | Very Good | Strong signal, high modulation possible | HD video, VoIP, fast transfers |
+| -61 to -67 | Good | Adequate signal for most applications | Stable browsing and video |
+| -68 to -72 | Fair | Signal getting weak, MCS begins to drop | Possible speed reductions |
+| -73 to -80 | Poor | Weak signal, retransmissions increase | Video buffering, VoIP issues |
+| < -80 | Very Poor | Signal too weak for reliable link | Frequent disconnections |
+**Interpretation:**
+RSSI tells you **how strong the AP signal is at the client**.
+More negative = weaker signal.
+----
+===== Noise Floor =====
+^ Noise (dBm) ^ Interference Level ^ Technical Meaning ^ Network Impact ^
+| -95 to -100 | Excellent | Channel is very clean | Maximum possible performance |
+| -90 to -94 | Very Good | Low interference | Stable operation |
+| -85 to -89 | Acceptable | Moderate interference present | Reduced top speed |
+| -80 to -84 | High | Significant interference | Retransmissions, lower MCS |
+| > -80 | Very High | Very noisy channel | Low throughput, high latency |
+**Interpretation:**
+Noise shows **how much interference exists on the channel**.
+Closer to zero = worse (more noise).
+----
+===== SNR — Signal-to-Noise Ratio =====
+^ SNR (dB) ^ Link Quality ^ Technical Meaning ^ User Experience Impact ^
+| > 40 | Excellent | Signal is much stronger than noise | Maximum throughput and stability |
+| 25 – 40 | Good | Good signal margin | HD video and VoIP stable |
+| 15 – 24 | Fair | Limited margin, medium modulation | Reduced speeds |
+| 10 – 14 | Poor | Small margin, frequent errors | Buffering and latency spikes |
+| < 10 | Very Poor | Signal nearly equal to noise | Unstable or dropped connection |
+**Interpretation:**
+SNR is the **most important indicator of real link quality**.
+Formula:
+SNR = RSSI – Noise
+Example:
+RSSI = -70 dBm
+Noise = -90 dBm
+SNR = 20 dB → Fair link quality
+----
+===== Support Troubleshooting Logic =====
+^ Situation ^ Likely Problem ^
+| Good RSSI + Good Noise = Good SNR | Healthy connection |
+| Good RSSI + Bad Noise = Low SNR | Interference issue |
+| Bad RSSI + Good Noise = Low SNR | Coverage issue |
+| Bad RSSI + Bad Noise | Coverage and interference problem |
+----
+===== Quick Field Reference =====
+| Metric | Main Question It Answers |
+| RSSI | How strong is the signal from the AP? |
+| Noise | How much interference is on the channel? |
+| SNR | How usable is the connection really? |
+===========================================
+----
+----
@@ Line 707: / Line 821: @@
 ----
 ----
+**{{ :networking:wireless_topic:wi-fi_standards:the-history-and-future-of-wi-fi_po_en_3609-6206-82_v0300.pdf |The-history-and-future-of-wi-fi}}**
+{{pdfjs 46em >:networking:wireless_topic:wi-fi_standards:the-history-and-future-of-wi-fi_po_en_3609-6206-82_v0300.pdf}}
+----
+----