업무 시스템 흐름
3-Tier · N-Tier
사용자 요청의 10계층 추적

Session 2 · Day 1 — 11:00 ~ 12:00 (60분)

아키텍처 패턴 · 계층별 컴포넌트 · 프로토콜·포트 · 응답시간 · 국내 실무 매핑

강사 박수현 · 🚀 젠아이랩스(GenAI Labs)

Session 2 — 회차 메타데이터

Session 2 — 오늘의 흐름 (60분)

Part A. 아키텍처 패턴 큰 그림

모놀리식 → 3-Tier → N-Tier → 마이크로서비스

4 슬라이드 · 약 7분

아키텍처 진화 — 30년 큰 그림

🎨 이미지 프롬프트: "Editorial horizontal timeline illustration on dark navy #0f1722 background, divided into 4 sequential decade panels separated by thin teal vertical dividers. Panel 1 labeled '1990s · Monolith': a single large beige mainframe-style box with a green CRT terminal in front, labels 'COBOL · C/S · HP9000 · Tandem' floating around. Panel 2 labeled '2000s · 3-Tier': three vertically stacked rectangular boxes labeled top-to-bottom 'Web · WAS · DB' connected by glowing arrows, side note 'Java EE · WebLogic · JEUS · NEIS · Gov24'. Panel 3 labeled '2010s · N-Tier + Cache': five horizontally connected boxes 'LB → Web → WAS → Cache(Redis) → DB' with a small load-balancer icon at the front, side note 'Naver · Kakao · KB'. Panel 4 labeled '2020s · Microservices': a hexagonal cluster of 6-8 small service nodes orbiting a central Kubernetes wheel icon, each node a different teal-purple tint, side note 'KakaoBank · Toss · Daangn'. Bottom ribbon across all panels: '95% of Korean Universities & Public Sector still run 3-Tier — the standard, not the trend'. Teal #00b894 and purple #6c5ce7 accents, clean editorial illustration style, 16:9. CRITICAL: All visible text MUST be in English ONLY (no Korean characters). Each label appears EXACTLY ONCE."

아키텍처 진화 — 30년 큰 그림

4가지 아키텍처 패턴 — 언제 어떤 것을 쓰는가?

Part B. 3-Tier 상세

Presentation · Business Logic · Data Layer

8 슬라이드 · 약 13분

3-Tier 큰 그림

┌──────────────────────────────────────────────────────────┐
│  ① Presentation Layer  (DMZ)                             │
│     Browser · Mobile App · 화면 렌더링·세션 표시          │
│     → Web Server (Nginx·Apache)                          │
├──────────────────────────────────────────────────────────┤
│  ② Business Logic Layer  (업무망)                        │
│     WAS — JEUS · WebLogic · Tomcat                        │
│     비즈니스 규칙·트랜잭션·외부 연계                       │
├──────────────────────────────────────────────────────────┤
│  ③ Data Layer  (업무망 깊숙이)                            │
│     DB — Oracle · Tibero · PostgreSQL                     │
│     Storage — SAN · NAS                                   │
│     영구 저장·트랜잭션 일관성·백업                         │
└──────────────────────────────────────────────────────────┘

🎨 이미지 프롬프트: "Editorial isometric architecture diagram on dark navy #0f1722 background showing the classic 3-Tier architecture. Three large vertically stacked horizontal floors connected by glowing teal arrows pointing downward (one-way). TOP FLOOR labeled 'Presentation Layer · DMZ Zone' (teal tint): a desktop monitor and a smartphone on the left, both connected via thin lines to a tall server rack labeled 'Web Server · Nginx · Apache'. MIDDLE FLOOR labeled 'Business Logic Layer · Internal Net' (purple tint): three server racks side by side labeled 'WAS · JEUS · WebLogic · Tomcat' with small gears floating around them representing transactions. BOTTOM FLOOR labeled 'Data Layer · Deep Internal' (orange tint): a cylindrical database icon labeled 'Oracle · Tibero · PostgreSQL' next to a storage array labeled 'SAN · NAS'. A vertical red 'ONE-WAY ONLY' arrow on the right side of all 3 floors showing direction. A red X mark blocking any arrow going from bottom to top, with a label 'NO direct back-channel'. Clean editorial illustration style, teal #00b894 and purple #6c5ce7 accents, 16:9. CRITICAL: All visible text MUST be in English ONLY. Each label appears EXACTLY ONCE."

3-Tier 큰 그림

① Presentation Layer — Web Server

② Business Logic Layer — WAS (Web Application Server)

③ Data Layer — DB · Storage

3-Tier — 망분리와 통신 경로 (KISA 가이드)

                  ┌─ 외부 인터넷 (Internet)
                  │
        ┌─────────▼──────────────────────────────────┐
        │  외부 방화벽 (NGFW · KCMVP)                 │
        └─────────┬──────────────────────────────────┘
                  │
                  ▼
        ┌──────────────────────────────────────────┐
        │  📍 DMZ                                  │
        │   ┌──────────────┐    ┌──────────────┐  │
        │   │  WAF / LB    │ →  │   Web Server │  │
        │   └──────────────┘    └──────────────┘  │
        └──────────────────────┬───────────────────┘
                               │ (단방향만 허용)
        ┌──────────────────────▼───────────────────┐
        │  내부 방화벽 (NGFW · 망간 통제)            │
        └──────────────────────┬───────────────────┘
                               ▼
        ┌──────────────────────────────────────────┐
        │  📍 업무망                                │
        │   ┌──────────────┐    ┌──────────────┐  │
        │   │     WAS      │ →  │      DB      │  │
        │   └──────────────┘    └──────────────┘  │
        │                                          │
        │              ┌──────────┐                │
        │              │ Storage  │                │
        │              └──────────┘                │
        └──────────────────────────────────────────┘

Part C. 사용자 요청 10계층 추적

Client → DNS → 보안 → LB → Web → APIGW → WAS → Cache → DB → SAN

14 슬라이드 · 약 22분

사용자 요청 — 10계층 흐름 전체도

┌───────────────────────────────────────────────────────────────────┐
│                                                                   │
│  ① Client            ②           ③            ④           ⑤    │
│  ┌────────┐ HTTPS ┌─────┐ A    ┌──────┐    ┌──────┐     ┌─────┐ │
│  │Browser ├──────▶│ DNS ├─────▶│ AntiD├───▶│  WAF ├────▶│ LB  │ │
│  │ Mobile │ 443   │     │ IP   │ DDoS │    │      │     │ L4  │ │
│  └────────┘       └─────┘      └──────┘    └──────┘     └──┬──┘ │
│                                                            │     │
│                                                ┌───────────┘     │
│                                                ▼                 │
│  ⑩            ⑨        ⑧         ⑦      ⑥                     │
│  ┌──────┐  ┌────┐  ┌──────┐  ┌─────┐  ┌──────┐                 │
│  │ SAN  │◀─┤ DB │◀─┤Cache │◀─┤ WAS │◀─┤APIGW │                 │
│  │Storage│  │    │  │ Redis│  │     │  │      │                 │
│  └──────┘  └────┘  └──────┘  └─────┘  └──────┘                 │
│                                          ▲                       │
│                                          │                       │
│              ⑤b                          │                       │
│           ┌──────┐                       │                       │
│           │  Web │───────────────────────┘                       │
│           │Nginx │ HTTP 8080                                     │
│           └──────┘                                               │
└───────────────────────────────────────────────────────────────────┘

🎨 이미지 프롬프트: "Editorial horizontal flow diagram on dark navy #0f1722 background showing a 10-stage user request flow as a clean left-to-right pipeline that loops back. Top row left-to-right: stage 1 'Client' (icon: laptop+phone) → stage 2 'DNS' (icon: globe with address) → stage 3 'Anti-DDoS' (icon: shield with arrows blocked) → stage 4 'WAF' (icon: brick wall + filter) → stage 5 'Load Balancer L4/L7' (icon: traffic distributor). The pipeline then bends at stage 5 and continues right-to-left on the bottom row: stage 6 'Web Server · Nginx' (icon: web server rack) → stage 7 'API Gateway' (icon: gate with API tag) → stage 8 'WAS' (icon: server with gears) → stage 9 'Cache · Redis' (icon: lightning bolt cylinder) → stage 9b 'DB Primary+Replica' (icon: two linked database cylinders) → stage 10 'Storage · SAN/NAS' (icon: striped disk array). Each stage is a card with a teal #00b894 left border and purple #6c5ce7 connecting arrows. Tiny red warning dot on every stage with label 'SPOF risk' floating subtly. Top-right corner has a small badge 'End-to-end latency budget: 2 sec'. Clean editorial illustration style, 16:9. CRITICAL: All visible text MUST be in English ONLY. Each label appears EXACTLY ONCE."

사용자 요청 — 10계층 흐름 전체도

① Client + ② DNS — 시작점

③ Anti-DDoS + ④ WAF — 외부 보안 1·2차 방어

⑤ Load Balancer — L4 / L7 분산

⑥ Web Server — 정적 컨텐츠 + Reverse Proxy

worker_processes auto;
worker_connections 4096;
proxy_pass http://was_upstream;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_read_timeout 30s;
gzip on;
limit_req zone=login burst=10;

⑦ API Gateway — 인증·라우팅·통제

⑧ WAS — 비즈니스 로직의 심장

⑨ Cache — DB 부하 분산

⑨ DB — 트랜잭션 최종 처리 지점

⑩ Storage — 데이터를 영속적으로 보관하는 계층

Part D. N-Tier 확장

4·5·6 Tier · 마이크로서비스 분해

6 슬라이드 · 약 10분

N-Tier — 3-Tier에서 어떻게 확장하는가?

Client → Web → WAS → Cache → DB

Client → Web → APIGW → WAS → Cache → DB

Web → APIGW → [Istio Mesh] → MS → Cache → DB

🎨 이미지 프롬프트: "Editorial vertical stacking illustration on dark navy #0f1722 background showing the evolution from 3-Tier to 6-Tier as four horizontal rows, each row a complete pipeline of connected boxes. ROW 1 labeled '3-Tier · baseline · 95% of KR systems': three boxes 'Web → WAS → DB' with thin teal arrows. ROW 2 labeled '4-Tier · +Cache · 1000+ concurrent users': four boxes 'Web → WAS → Cache(Redis) → DB' with the new 'Cache' box highlighted in glowing teal. ROW 3 labeled '5-Tier · +API GW · public API era': five boxes 'Web → API GW(Kong) → WAS → Cache → DB' with 'API GW' highlighted in glowing purple. ROW 4 labeled '6-Tier · +Service Mesh · 50+ microservices': six boxes 'Web → API GW → Service Mesh(Istio) → MS Cluster → Cache → DB' with 'Service Mesh' highlighted in glowing orange and a small Istio honeycomb icon. Right-edge stacked counter ribbon showing '3T: 95% · 4T: included · 5T: 5% · 6T: <1%' of Korean systems. Tiny KR brand silhouettes next to relevant rows: 'Kakao · Naver · Toss' next to 6-Tier. Clean editorial illustration style, teal #00b894 and purple #6c5ce7 accents, 16:9. CRITICAL: All visible text MUST be in English ONLY. Each label appears EXACTLY ONCE."

N-Tier — 3-Tier에서 어떻게 확장하는가?

마이크로서비스 — 언제·어떻게 분해하는가?

🎨 이미지 프롬프트: "Editorial split illustration on dark navy #0f1722 background contrasting Monolith vs Microservices. LEFT HALF labeled 'Before · Monolithic 3-Tier': one large solid block labeled 'Single Codebase · Single Deploy · Single DB' with cracks running through it; thin red labels around it 'deploy 1 month · cross-team blocking · partial fault = total down'. A small dashed arrow points right with a label 'Decompose by Bounded Context'. RIGHT HALF labeled 'After · Microservices': five floating hexagonal service nodes arranged in a constellation, each clearly labeled — 'Auth Service', 'Approval Service', 'Board Service', 'Mail Service', 'File Service' — each with its own small DB cylinder underneath labeled 'Own DB' (or 'Object Store' for File). Subtle teal connecting lines between hexagons represent service-mesh calls. Bottom strip across both halves: '4 boxes must be ✓ before MSA — Deploy time, Team blocking, Partial fault blast radius, Ops headcount 30+'. Two-Pizza Team icon (small pizza+people) appears next to one of the hexagons. Clean editorial illustration style, teal #00b894 and purple #6c5ce7 accents, 16:9. CRITICAL: All visible text MUST be in English ONLY. Each label appears EXACTLY ONCE."

마이크로서비스 — 언제·어떻게 분해하는가?

3-Tier vs 마이크로서비스 — 결정 매트릭스

Part E. 국내 실제 시스템 매핑

대학 학사 · 공공 그룹웨어 · 금융 코어

5 슬라이드 · 약 8분

사례 ① — 대학 학사 시스템 (학생 1.2만 명)

사례 ② — 공공 그룹웨어 (5,000명 사용)

사례 ③ — 금융 코어 시스템 (고객 500만 명·24/7)

4 사례 비교 — 내 시스템은 어디에 가까운가?

Part F.
응답시간 분해 + 워크시트 연계

8 슬라이드 · 약 13분

응답시간 분해 — SLA 「화면당 2초」를 10계층에 배분

🎨 이미지 프롬프트: "Editorial horizontal stacked bar chart illustration on dark navy #0f1722 background visualizing the '2-second SLA latency budget' broken down across 10 layers. ONE long horizontal bar at the center spanning most of the canvas labeled '2000 ms SLA Budget · per screen response'. The bar is divided into colored segments proportional to their share: tiny teal slices for 'Client 100ms · DNS 50ms · Anti-DDoS 5ms · WAF 5ms · LB 5ms · Web 10ms · API GW 5ms · Cache 5ms · Network 115ms', and two HUGE purple slices labeled prominently 'WAS · 800ms' and 'DB+Storage · 900ms' marked with red star icons ★. Above the bar a thinner reference bar showing actual measured times totaling '1,482 ms · 518 ms slack' in green. Right side has a vertical legend with each layer color-coded. Bottom callout box says 'WAS + DB = 85% of the budget → tune these FIRST (Jennifer, Pinpoint, pgBadger)'. A red magnifying glass icon hovers over the two large purple slices. Clean editorial illustration style, teal #00b894 / purple #6c5ce7 / red accents, 16:9. CRITICAL: All visible text MUST be in English ONLY. Each label appears EXACTLY ONCE."

응답시간 분해 — SLA 「화면당 2초」를 10계층에 배분

병목 식별 — APM으로 SLA 위반 구간 찾기

흐름 설계 — TA 의사결정 체크리스트

흐름 설계 — 주니어 TA가 흔히 하는 실수 5가지

Session 2 — 정리

Session 2 — 마무리