Each RAT's access-control features arranged as the gate pipeline a request passes. Switch RAT with the buttons; click any feature node for its card — what it is, benefit, recommended parameters and the counters it moves. The fullest per-feature detail lives on each technology's optimization page (linked from every card).
The UE timers that shape every setup, resume and recovery — MO [DU] ue-timer-constants / ue-timer-const-info, defaults verbatim from the Samsung DU Parameter Description (these supersede the older catalog values; always RTRV your release template first).
| Leaf | Range | Default | What it times · optimization |
|---|---|---|---|
| t300 | ms100 … ms2000 | ms200 | Started on RRCSetupRequest; stops on RRCSetup/Reject. Too short → premature setup-fail counts; too long → worse RRC Setup Time (5214) |
| t301 | ms100 … ms2000 | ms200 | Started after RRCReestablishmentRequest |
| t304 | … ms10000 | ms1000 | Handover / PSCell completion (reconfig-with-sync) — widen on large cells / marginal targets |
| t310 | … ms6000 | ms2000 | Out-of-sync (physical-layer problem) detection — the direct lever between retainability (hold good links) and fast recovery |
| t311 | … ms30000 | ms5000 | RRC re-establishment cell-search window — widen where neighbour search is slow (deep indoor) |
| t319 | ms100 … ms2000 | ms600 | Started on RRCResumeRequest (from INACTIVE) — the resume-side timeout |
| n310 | … n20 | n10 | Consecutive out-of-sync before t310 starts — lower = more sensitive RLF detection |
| n311 | … n10 | n1 | In-sync count that cancels t310 — raise to require a steadier recovery |
t300 is the accessibility lever (setup supervision); t310/t311/n310/n311 are the retainability↔recovery levers (RLF declaration & re-establishment search); t319 is the resume lever. Move them together — a shorter t310 recovers faster but drops recoverable links.Stage-0 access — MO [DU] ul-physical-resource-config/prach-config & SON rach-optimization. Governed by FGR-RS0121/RS0122 (Random Access Support). A weak SSB beam shows in the per-beam RACH family (5243) before it shows anywhere else.
| Leaf | Range | Default | Effect · optimization |
|---|---|---|---|
| preamble-trans-max | n3 … n200 | n10 | Max preamble transmissions (TS 38.321 §5.1.4) — raise where access is coverage-limited |
| power-ramping-step | dB0 / dB2 / dB4 / dB6 | dB2 | Preamble power ramp per attempt — dB4 converges faster at the edge (more interference) |
| ra-contention-resolution-timer | sf8 … sf64 | sf64 | Msg4 contention-resolution window — shorten for faster failure/retry |
| msg1-fdm | n1 / n2 | n1 | RACH occasions in frequency (FGR-RS0121) — n2 doubles capacity under PRACH congestion |
| prach-configuration-index | 0 … 255 | (plan) | PRACH format/periodicity (TS 38.331 §6.3.2) — denser = more RACH opportunities; cell-lock to change |
| ssb-per-rach-occasion-choice | … four | one | SSB→RO mapping density — match to SSB beam count; wrong mapping starves beams (check 5243) |
| cb-preambles-per-ssb | 1 … 64 | 56 | Contention preambles per SSB — lower only when reserving CFRA; too low = collisions |
| zero-correlation-zone-config | 0 … 15 | 12 | Preamble cyclic-shift spacing — must match cell radius; wrong value = ghost/missed preambles |
The hard limits that cap concurrent context (protecting existing users) and the overload switches that shed new access under congestion — the direct levers behind Admission Control Fail Rate (LTE reject causes · NR Families 5147/5148).
| Leaf | RAT | Default | Optimization |
|---|---|---|---|
| max-enb-call-count / max-call-count | LTE | 18000 / — | eNB & cell UE-count caps (SW4101) — size to channel-card capability |
| call-cac-threshold-for-normal | LTE | 90% | Lower to 80–85% to intervene before overload; emergency/HO keep their own higher thresholds |
| call-count-cac-usage | NR | use | Master call-count gate (CC0301) — behind CacFail_GnbCallCount (5148) |
| call-cac-threshold | NR | 100.00 | Lower to 80–90% for early intervention |
| qos-based-cac-usage | NR | use | PRB-aware GBR admission (CC0302) — behind CacFail_QosBasedCount (5147) |
| slice-cac-usage | NR | not-use | Enable when slicing is sold (CC0303) — per-slice-group portions; read per S-NSSAI (5438) |
| call-protect-usage / paging-protect-usage | NR | not-use | Enable (FGR-LC0303) — caps RRCSetup/Resume + SgNB-Add + paging per unit time to protect CPU |
| preemption-trigger-arp-priority | NR | 3 (1..15) | ARP at/above which a new call preempts (CC0401) — lower = more aggressive priority protection |
Denied_*/Discarded_*; NR Families 5180/5185 denied/discarded paging. When accessibility dips, check these before blaming RF — a rejected-by-design request is not a fault.Sources: Samsung eNB (LTE) Feature Description SVR24B (LTE-SW features), 5G RAN Feature Description SVR25B (FGR-CC/BC/LC features), and the eNB / CU-ACPF (SVR25A) / DU (SVR22B) Parameter Descriptions (MO leaf, range, default). Every feature code, name, MO and default is verbatim; recommended values are Samsung optimization guidance. Full per-feature cards on the LTE / NSA / SA optimization pages.