Monitoring Network Performance in China
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ThousandEyes provides visibility into network performance and critical operations for enterprises, particularly focusing on challenges in China, including high latency, packet loss, and stringent censorship. The document discusses methods for benchmarking network performance, identifying DNS issues due to tampering, and monitoring blocked page components. Best practices are recommended for adjusting alerts and continuously monitoring the dynamic Chinese internet environment.
Monitoring Network Performance in China
- 2. 2 About ThousandEyes ThousandEyes delivers visibility into every network your organization relies on. Founded by network experts; strong investor backing Relied on for " critical operations by leading enterprises Recognized as " an innovative " new approach 31 Fortune 500 5 top 5 SaaS Companies 4 top 6 US Banks
- 3. 3 • High latency and packet loss are common • 10 backbone access points (i.e., “choke points”) • 2 dominant, government-controlled ISPs: China Unicom (North), China Telecom (South) – Underdeveloped and congested – Few peering points in between • Highly sophisticated censorship system – Great Firewall – Great Cannon A Different Internet in China
- 4. 4 • IP blocking – Routers drop all packets going to blacklisted IP addresses – Lightweight • DNS tampering – Cache poisoning – Keyword-based hijacking The Great Firewall
- 5. 5 • Deep packet inspection and keyword filtering – Resource-intensive The Great Firewall Read more: https://blog.thousandeyes.com/deconstructing-great-firewall-china/
- 6. 6 • Set up Network tests to benchmark performance metrics like latency and packet loss • Expect: – Higher latency and loss • Especially for traffic crossing into or out of China – Changing conditions due to censorship and diurnal patterns Baseline Network Performance Read more: https://blog.thousandeyes.com/benchmarking-network-performance-china/
- 7. 7 Higher loss and latency from China Clear diurnal patterns in outbound traffic Use Reports to Benchmark Performance
- 8. 8 Compare HK with geographically close locations in China: Foshan, Zhuhai, Guangzhou Performance differences can then be attributed to crossing the Great Firewall Use Hong Kong for Comparison
- 9. 9 • DNS packets often go missing – Frequently congested, unreliable networks – DNS poisoning and hijacking • Cloud Agents in China use local ISP caches • Use DNS Server and Trace tests and alerts to check if records: – Are always available – Have the correct mappings – Are served up quickly DNS Issues Read more: https://blog.thousandeyes.com/monitoring-application-delivery-china/
- 10. 10 DNS lookup of “dns- plx.ewr1.nytimes.com” returns incorrect mappings to blocked IPs of services including Facebook, Dropbox Tests to these blocked IPs are then blocked in China Telecom and China Unicom DNS Server Test: NYTimes.com A record
- 11. 11 DNS lookup of “ns1.p24.dynect.net” returns correct mapping, suggesting DNS tampering on NYTimes nameserver’s A record Test traffic from China makes it through to the Dyn nameserver Evidence of DNS Tampering
- 12. 12 Lookup of NYTimes.com A record returns incorrect mappings to blocked IPs Impossibly low resolution times suggest DNS cache poisoning Evidence of DNS Cache Poisoning
- 13. 13 • Page objects with blocked keywords or domains may fail to load and slow down page load times • Watch out for: – Google: fonts, APIs, ads, Google Analytics – Facebook – Adobe Typekit – Marketo • Use the waterfall in Page Load and Transaction tests to monitor for objects that fail to load Blocked Page Components Read more: https://blog.thousandeyes.com/monitoring-application-delivery-china/
- 14. 14 Objects from blocked sites Facebook and Google have long wait times and fail to load Page Load Test: Starbucks US from China
- 15. 15 China-optimized webpage sees much lower object load times Still room for improvement: Google object has long DNS time Page Load Test: Starbucks China from China
- 16. 16 • Scope alerts to China agents and recalibrate thresholds • Consider ISP- specific Path Trace alerts Alerting Read more: https://blog.thousandeyes.com/monitoring-application-delivery-china/
- 17. 17 q Adjust your expectations and alerts based on Network test data q Use Reports to analyze data by country q Also benchmark: q CDN providers q Data center/colocation providers q Continuously monitor important services in China’s volatile environment Best Practices for Monitoring in China q Understand the difficulties unique to the Chinese Internet and adjust your monitoring strategy accordingly q 2 ISPs with few peering points q Underdeveloped and congested q Only 10 access points q Stringent censorship q DNS poisoning and hijacking q Blocked page objects
- 18. 18 See what you’re missing. Watch the webinar: https://www.thousandeyes.com/resources/network-performance-in-china-webinar