1
# 路由跳数延迟计算
2
hops = 15  # 典型的跨省访问跳数
3
processing_delay_per_hop = 2  # ms，路由器处理延迟
4
physical_delay = 20  # ms，光纤传输延迟
5

6
total_delay = physical_delay + hops * processing_delay_per_hop
7
print(f"总延迟: {total_delay} ms")
8
# 输出：总延迟: 50 ms

1
# CDN 推荐的缓存头配置
2
# 静态资源（CSS、JS、图片）
3
Cache-Control: public, max-age=31536000, immutable
4

5
# HTML 页面（需要协商）
6
Cache-Control: no-cache
7
ETag: "abc123"
8

9
# API 响应（不缓存）
10
Cache-Control: no-store

1
# CDN 缓存规则配置示例
2
rules:
3
  - pattern: "*.css"
4
    cache_control: "public, max-age=31536000, immutable"
5
    edge_ttl: 31536000 # 边缘缓存 1 年
6

7
  - pattern: "*.js"
8
    cache_control: "public, max-age=31536000, immutable"
9
    edge_ttl: 31536000
10

11
  - pattern: "*.jpg, *.png, *.webp"
12
    cache_control: "public, max-age=31536000"
13
    edge_ttl: 2592000 # 边缘缓存 30 天
14

15
  - pattern: "*.html"
16
    cache_control: "no-cache"
17
    edge_ttl: 300 # 边缘缓存 5 分钟，强制协商
18

19
  - pattern: "/api/*"
20
    cache_control: "no-store"
21
    edge_ttl: 0 # 不缓存

1
# 缓存命中率计算
2
total_requests = 1000000
3
cache_hits = 920000
4
cache_misses = total_requests - cache_hits
5

6
hit_rate = cache_hits / total_requests * 100
7
print(f"缓存命中率: {hit_rate:.1f}%")
8
print(f"回源请求: {cache_misses}")
9

10
# 输出：
11
# 缓存命中率: 92.0%
12
# 回源请求: 80000

1
# 源站 Nginx 配置
2
server {
3
    listen 80;
4
    server_name origin.example.com;
5

6
    location /static/ {
7
        alias /var/www/static/;
8

9
        # 设置缓存头
10
        expires 1y;
11
        add_header Cache-Control "public, immutable";
12

13
        # 开启 gzip
14
        gzip on;
15
        gzip_types text/css application/javascript image/svg+xml;
16

17
        # 支持 Range 请求（视频分段）
18
        add_header Accept-Ranges bytes;
19
    }
20
}

1
# CDN 缓存配置
2
domain: cdn.example.com
3
origin: origin.example.com
4

5
cache_rules:
6
  - path: "*.css"
7
    ttl: 31536000 # 1 年
8
    gzip: true
9

10
  - path: "*.js"
11
    ttl: 31536000
12
    gzip: true
13

14
  - path: "*.jpg, *.png, *.webp"
15
    ttl: 2592000 # 30 天
16
    image_optimize: true # 图片优化
17

18
  - path: "*.mp4, *.webm"
19
    ttl: 86400 # 1 天
20
    range: true # 支持分段请求

1
# 静态资源加载时间对比
2
# 假设资源大小 100KB，用户到源站距离 2000km
3

4
# 无 CDN
5
origin_latency = 80  # ms，RTT
6
origin_bandwidth = 10  # Mbps
7
load_time_no_cdn = origin_latency + (100 * 8 / origin_bandwidth)
8
print(f"无 CDN 加载时间: {load_time_no_cdn:.0f} ms")
9

10
# 有 CDN
11
cdn_latency = 15  # ms，RTT 到边缘节点
12
cdn_bandwidth = 100  # Mbps
13
load_time_with_cdn = cdn_latency + (100 * 8 / cdn_bandwidth)
14
print(f"有 CDN 加载时间: {load_time_with_cdn:.0f} ms")
15

16
improvement = load_time_no_cdn / load_time_with_cdn
17
print(f"性能提升: {improvement:.1f}x")
18

19
# 输出：
20
# 无 CDN 加载时间: 160 ms
21
# 有 CDN 加载时间: 23 ms
22
# 性能提升: 7.0x

1
# CDN 安全配置建议
2
security:
3
  # 强制 HTTPS
4
  force_https: true
5
  tls_version: "1.2+"
6
  hsts: "max-age=31536000; includeSubDomains"
7

8
  # WAF 规则
9
  waf:
10
    enabled: true
11
    rules:
12
      - sql_injection: block
13
      - xss: block
14
      - path_traversal: block
15

16
  # 访问控制
17
  access_control:
18
    ip_whitelist: ["10.0.0.0/8"]
19
    referer_whitelist: ["example.com"]
20

21
  # 速率限制
22
  rate_limit:
23
    requests_per_second: 100
24
    burst: 200
25

26
  # 源站保护
27
  origin_protection:
28
    hide_origin_ip: true
29
    origin_pull_timeout: 30s