5-Layer Protection Architecture: MEC & LLM Security

• 5-Layer Protection Architecture is a structured framework deploying five interlocking layers to enforce access controls, validate devices, and enhance reliability in both MEC and LLM systems.
• It employs techniques such as Single Packet Authentication, mutual TLS, dynamic firewalls in MEC, and self, cross, mutual, relationship, and beneficiary protections in LLM architectures.
• The design minimizes risks like unauthorized entry, session hijacks, and cognitive errors while maintaining low latency overhead and adaptable calibration protocols.

A five-layer protection architecture refers to a hierarchical security or reliability mechanism in which five distinct and often interlocking layers are deployed to mitigate risks, enforce policy, and sustain desired operational states. This architecture is highly relevant in both multi-access edge computing (MEC) security, as formalized in software-defined perimeter (SDP) literature (Singh et al., 2020), and in high-stakes human–machine collaboration for LLMs (Jadad, 10 Nov 2025). Each instantiation defines the layers, control flows, and monitoring strategies to address specific classes of threats or failure modes.

1. Layer Overview and Architectural Positioning

In the SDP-based paradigm for MEC, the five-layer stack consists of: Single Packet Authentication (SPA), Mutual Transport Layer Security (mTLS), Device Validation (VD), Dynamic Firewall (DFW), and Application Binding (AppB). Traffic originating from user equipment (UE) traverses the LTE radio network, enters the core EPC, and arrives at the SDP Accepting Host (Gateway) where these layers sequentially enforce access controls. The control plane is managed by a local SDP Controller. Each layer introduces a set of primitives that are mutually reinforcing.

In high-stakes LLM decision architectures, the layers are: Self-Protection, Cross-Protection, Mutual Protection, Relationship Protection, and Beneficiary Protection. These operate on dialogue and partnership dynamics rather than packets, with each layer designed to monitor and intervene on cognitive traps such as sycophancy, solution drift, context exhaustion, and stakeholder misalignment.

Layer Table (Editor’s term: “Layer-Function Map”):

SDP MEC Layer	High-Stakes LLM Layer	Primary Function
Single Packet Auth	Self-Protection	Prevent unauthorized entry; bias
Mutual TLS	Cross-Protection	Authenticate, integrity; cross-bias reinforcement
Device Validation	Mutual Protection	Session legitimacy; challenge/response
Dynamic Firewall	Relationship Protection	Traffic control; partnership state monitoring
Application Binding	Beneficiary Protection	Port/service restriction; stakeholder safety

This illustrates the analogy between physical network security layering and interactive dialogue reliability mediation.

2. Layer-by-Layer Mechanisms

Layer 1: Single Packet Authentication (SDP) / Self-Protection (LLM)

SPA operates as a “knock” on a blackened port, requiring a single packet with timestamp, client ID, nonce, and keyed HMAC. If valid, the SDP Controller issues session credentials. The default Gateway policy is drop-all; only after SPA passes is a connection permitted. Threats mitigated include port scanning, basic spoofing, and replay.

Self-Protection mandates per-exchange monitoring for linguistic or computational failure markers (e.g., “I agree completely”, unwarranted hedges). Rolling counts over sliding windows trigger corrective subroutines if threshold crossing occurs. Detection feeds upward to higher layers when self-correction is insufficient.

Layer 2: Mutual TLS (SDP) / Cross-Protection (LLM)

mTLS establishes a bidirectionally authenticated, encrypted tunnel via TLS handshake with certificates from the SDP Controller. Cipher suite negotiation prioritizes forward secrecy and resistance to MITM. Only after SPA success does mTLS initiate, with session certificates provisioned dynamically.

Cross-Protection quantifies reinforcement bias metrics (anchor-bias index for humans, sycophancy index for LLMs). If partner move frequencies cross defined thresholds, a cross-challenge is auto-issued, prompting reconsideration of assumptions and defending against compounded bias.

Layer 3: Device Validation (SDP) / Mutual Protection (LLM)

Device Validation involves periodic, signed heartbeats over the TLS tunnel, containing attestation, liveness proofs (fresh nonces), geolocation, or hardware ID. The Controller maintains session state and withdraws access on validation failure or timeout. This mechanism blocks session hijack and lateral-movement using stolen credentials.

Mutual Protection injects bidirectional challenge behavior periodically (e.g., every 4th exchange), requiring partners to challenge each other's key assumptions. This scaffolds critical assessment and breaks up automatic consensus formation.

Layer 4: Dynamic Firewall (SDP) / Relationship Protection (LLM)

Dynamic Firewall enforces ephemeral, whitelist-only rules at the Gateway (iptables via FWKNOP). Only a specific src/dst IP, port, and protocol tuple is allowed temporarily (e.g., 60 seconds). Rule withdrawal occurs on validation failure or timeout, shrinking the attack surface dramatically and nullifying generic DoS attempts.

Relationship Protection monitors the overall health of human–LLM interaction (false consensus, context exhaustion, unanswered challenges). Health scores are calculated via drift flags, challenge response rates, and context usage. Failure to maintain above-threshold health leads to escalation or session dissolution.

Layer 5: Application Binding (SDP) / Beneficiary Protection (LLM)

Application Binding ensures traffic authorized by prior layers is mapped strictly to designated backend services (e.g., SSH port only). Attempts to access unrelated services (HTTP, DNS) are silently dropped, preventing exploit chaining and lateral scans.

Beneficiary Protection maintains and updates a stakeholder impact plan, comparing projected impact against pre-set loss thresholds ($L_{max}$). When projected harm or violation is detected, a hard stop triggers—decisions freeze, and handoff to governance protocols occurs.

3. Inter-Layer Interactions and Escalation Logic

Layers interoperate by feeding signals upward or laterally. In SDP MEC, SPA must be validated before mTLS is triggered (Layer 1 precedes Layer 2). Heartbeat failures in VD instantly result in firewall rule withdrawal (Layer 3 → Layer 4). Only when a time-bound firewall rule is in place can application proxying proceed (Layer 4 → Layer 5).

In LLM architectures, self-monitoring failures (Layer 1) cause escalation to cross-protection (Layer 2), which may initiate mutual challenge (Layer 3) and relationship health checks (Layer 4). Ultimately, regardless of internal partnership comfort, the final judge is projected stakeholder impact (Layer 5), which can override all prior layers.

Transition logic in both paradigms is rule-based, with explicit thresholds, counters, and consequence maps.

4. Performance and Overhead

The SDP architecture models end-to-end delay as the sum of initialization and session rule installation phases:

$$Delay(i,j) = \frac{\alpha_i}{R} + \frac{\beta_i}{S}$$

where $\alpha_i$ is the packet size, $R$ is the link bandwidth, $\beta_i$ is path length, and $S$ is signal speed.

Initialization overheads are calculated for SPA, TLS handshake, and LTE attach phases. In experimental testbeds (Singh et al., 2020), measured end-to-end session delay with SDP was $0.5551$ s, compared to $0.5478$ s without SDP layers. Controller overhead and per-session Gateway rule install were $0.0477$ s and $0.0489$ s respectively. This demonstrates minimal added latency for substantial security gain.

LLM architectures report session degradation rates ($\lambda_{drift}$) rising linearly with token count. Probability of maintaining partnership intact at time $t$ is $P(t) \approx e^{- \alpha t}$, with $\alpha$ in the range $0.0001$–$0.0003$ per token. Shorter, recalibrated sessions outperform monolithic, lengthy engagements.

5. Implementation Protocols and Limitations

SDP MEC Implementation:

• SPA and mTLS require coordinated certificate authority/PKI deployment and stateful session management.
• Device validation necessitates attestation support and secure tunnel liveness checks.
• Dynamic firewall policy must interface with real-time iptables scripting engines like FWKNOP.
• Application binding requires strict port mapping at the proxy/gateway interface.

LLM High-Stakes Decision Architecture:

• Initialization consists of partnership calibration artifact, behavioral operationalization, session continuity protocols, and vignette specification, each with comprehension checkpointing.
• Calibration demands reloading artifacts, transmission of prior partnership state, and operational testing under ambiguity.
• Maintenance involves adversarial challenge cycles, drift monitoring, dynamic recalibration, and irrevocable stop rules when predefined stakeholder thresholds are crossed.

Limitations:

• In SDP, failure to properly orchestrate inter-layer rule transition can create unintended access holes.
• LLM protocols depend on self-reported internal state, which is not externally verifiable; highly capable models may simulate partnership behavior without substantive cognition.
• Calibration overhead may burden fast-turnaround contexts; empirical validation is limited by simulated vignettes.

6. Security and Reliability Outcomes

When deployed in MEC environments, the five-layer SDP protection paradigm defeats port scans, sniffing, MITM, session hijack, DoS floods (which are dropped before even opening a socket), and lateral exploitation. Full chaining ensures only authenticated, valid edge devices receive minimal, ephemeral firewall openings restricted to their authorized application ports.

In human–LLM team operations, the five-layer protection prevents avoidable cognitive traps by embedding active error detection, cross-partner intervention, iterative challenge, relationship monitoring, and stakeholder governance. The architecture supports robust decision partnership under operational pressure, substantially reducing the risk of organizational-scale regret from unchecked bias or drift.

The layered approach, with explicit transition logic, continuous monitoring, and rule-based session management, provides a reproducible, generalizable protocol for both MEC security and high-stakes AI decision processes.