Cost Control Tips For Korean CN2 Site Clusters: Bandwidth Billing And Resource Allocation Recommendations

When providing stable access to Chinese users via CN2 links in South Korea, bandwidth and billing become the main costs. First, clarify: site networks (multiple domains/multiple sites) will amplify sudden traffic spikes; CN2 is typically billed on a 95th, fixed bandwidth, or per traffic basis, with different billing methods affecting the strategy. This article focuses on practical application, helping you implement traffic calculations, route selection, bandwidth smoothing, speed limiting, and resource allocation.

Calculation formula: Peak bandwidth (Mbps) ≈ concurrent visits × Average page size (MB) × 8 / Average page load time (s). For example, 500 concurrent users, 1.2MB page size, 4s loading time, bandwidth ≈ 500×1.2×8/4=1200Mbps. It is recommended to order or negotiate with a minimum margin of 1.2~1.5 times.

If charged as 95th: focus on smooth peak periods to avoid short-term suddenness; If bandwidth is fixed: you can strive for tiered discounts or guaranteed bandwidth; Billing by flow: optimized caching and CDN optimization. Negotiation skills: Request trial periods, peak threshold thresholds, excess price tiering, seasonal discounts, and cross-region bandwidth sharing terms.

Schedule non-real-time tasks (backup, synchronization, batch push) during off-peak periods and execute them in batches. Example: Use rsync + cron to split and upload large files and set sleep intervals; Limit the number of concurrent threads during backup. For site networks, resources from different domain names can be synchronized in rotation, reducing the need for all sites to simultaneously attract traffic.

Common tools: vnStat (long-term traffic statistics), iftop/top (real-time monitoring), iperf3 (link band), installation and basic commands: apt install vnstat; vnstat -u -i eth0； iperf3 -c server_ip -t 60 -P 4 tests concurrent bandwidth. Regularly export 95th statistics to keep bill comparisons.

Simple HTB speed limiting example: tc qdisc add dev eth0 root handle 1: htb default 30; tc class add dev eth0 parent 1: classid 1:1 htb rate 1000mbit; tc class add dev eth0 parent 1:1 classid 1:10 htb rate 200mbit ceil 1000mbit； Paired with TC filter, speed limits are assigned based on IP/port. For clusters, traffic can be labeled and policies applied by container/virtual IP, or Wondershaper can be used to quickly limit interface bandwidth.

Migrate images, JS, CSS, videos, etc. to the CDN or Korean edge nodes. Practical steps: 1) Point the static domain to the CDN; 2) Enable Cache-Control at the origin and configure long caches; 3) Use Nginx proxy_cache as L2 cache. Image compression tools (cwebp, jpegoptim) enable Brotli/Gzip and HTTP/2 push, which can significantly reduce bandwidth.

Use containers (Docker/LXC) to isolate each station: docker run -- name site1 -- cpus="1.0" -- memory="512m" ..., or use systemd.slice and cgroups to set finer resource limits. Disk I/O is limited by ionice and blkio cgroup, preventing a single station from filling I/O and causing slower response to other stations, extending download times, and increasing bandwidth usage.

Answer: The key is to "shave peaks and fill valleys." Specific steps: 1) Enable speed limiting or streaming shunting (tc+iptables mark) before peak times; 2) Deferring or buffering responses to non-critical requests; 3) Use CDN and edge caching to reduce large volumes of requests; 4) Spread large file uploads/distributions through scripts during off-peak periods. Coordinate with daily/weekly monitoring of the 95th trend, adjust strategies, and aim to negotiate lower prices based on historical peaks.

Answer: First, conduct A/B testing: use iperf3 and real access to monitor latency, packet loss, and jitter among different vendors; Compare prices and SLAs for GIA/CN2 GT and similar schemes. If the goal is minimal latency and budget allowance, CN2 GIA is chosen and supplemented with CDN; If your budget is sensitive, choose the CN2 GT or a balanced solution with cheaper bandwidth, and prioritize caching and speed limiting to reduce outbound traffic.

Answer: Do four things regularly: 1) Check the bandwidth curve and the 95th change every week; 2) Monthly evaluation of static resource cache hit rates and optimization; 3) Set time windows for high-bandwidth tasks and automate scheduling (cron/queue); 4) Maintain records of supplier bill reconciliation and price negotiation. Combined with automatic alerts (Netdata/Prometheus), expansion or speed limiting strategies are automatically triggered when traffic approaches thresholds, preventing sudden bill spikes.