Due to long geographical distances and complex international outbound routes, mainland China often encounters high network latency, severe packet loss, and unstable connections when accessing US VPSs, severely impacting user experience and business operational efficiency. How can we optimize high latency on US VPSes? Understanding the nature of high latency is key to finding the right optimization solution.
Analysis of the Reasons for High Latency When Accessing US VPSs from Mainland China
1. Long Physical Distance: The distance between mainland China and the US is over 10,000 kilometers. Signal transmission requires multiple fiber optic nodes and submarine cables. This physical distance determines the minimum theoretical latency limit. Even with ideal routes, one-way latency typically never exceeds 70-90 milliseconds.
2. Complex Cross-Border Routes: Cross-border networks rely on submarine cables, multiple layers of network operators, and involve multiple international outbound routes. Most common routes are BGP routes, which traverse multiple transit nodes, resulting in numerous hops and suboptimal routing, leading to increased latency and even packet loss.
3. Network Congestion and Bandwidth Bottlenecks: Cross-border bandwidth resources are limited, especially during peak hours in the evening, when congestion is significant. This increases packet queueing times and slows response times.
4. Network device performance and configuration issues: Excessive server or transit network equipment load and improper firewall configuration can also cause packet processing delays.
Optimizing latency for mainland China access to US VPSs
To address the above issues, optimization paths primarily focus on improving line quality, routing, reducing hops, and utilizing technical means to divert traffic. Several effective measures are listed below.
1. Selecting high-quality international optimized lines
Ordinary BGP lines often suffer from congestion. Choosing a CN2 GIA dedicated line or similar high-quality international dedicated lines is the most effective optimization method. CN2 GIA dedicated lines connect directly to China Telecom's backbone network, avoiding traditional BGP multi-layer forwarding, reducing routing hops to less than 10, and ensuring bandwidth during evening peak hours with extremely low packet loss. If your VPS provider supports line selection, it is recommended to purchase a US VPS equipped with a CN2 GIA or other high-quality dedicated line.
2. Utilizing CDN distribution acceleration
CDNs (content delivery networks) play a crucial role in optimizing the access experience. By deploying nodes within mainland China, CDNs cache static resources closest to the user, significantly reducing access latency. For static content (images, JavaScript, CSS, etc.), CDN acceleration can significantly reduce load times. For dynamic requests, intelligent DNS resolution can be combined to direct user requests to nodes with lower latency.
3. Utilize Intelligent Routing Optimization Services
Some service providers offer cross-border intelligent routing acceleration services. These services monitor line status in real time and dynamically select the optimal path to avoid congested nodes. For example, accelerator software or hardware can be used to direct traffic to low-latency links. VPS providers offer elastic dedicated lines and intelligent acceleration gateways to improve connection quality. Enterprises can consider leasing dedicated lines or utilizing cloud providers' elastic public IP optimization features.
4. Utilize Multi-BGP or Multi-Exit Strategies
Multi-BGP refers to servers connecting to multiple international exit carriers and intelligently switching exits based on line status. When a line is congested, it automatically switches to another, more accessible line, achieving load balancing and failover for cross-border access. A multi-line BGP solution can effectively improve the availability and stability of cross-border access, preventing service interruptions caused by single-line failures.
5. Deploy a transit node or jump server
If latency is too high when connecting directly to a US VPS and is difficult to optimize, consider deploying a transit node in Asia (such as Hong Kong, Japan, and Singapore) as an access bridge. Using transit nodes can optimize routing and shorten access paths. For some application scenarios, transit nodes can significantly improve access response speed. This solution requires a well-designed proxy forwarding strategy to avoid adding additional latency.
6. Optimize server configuration and application architecture
Server-side performance optimization is equally important. Disable unnecessary firewalls or security policies to reduce packet filtering time. Optimize applications to reduce resource usage and response time for individual requests. Effectively utilize cache to avoid repeated requests to databases and disks. Furthermore, adopting a distributed architecture to disperse data and computing can reduce single point pressures and improve overall response speed.
Technical Details and Practical Recommendations:
1. Test and diagnose line bottlenecks. First, accurately locate the source of latency. Use tools such as ping, traceroute, and mtr to monitor cross-border link hop counts and packet loss. Based on the diagnostic results, determine whether it's a physical link issue or node congestion.
2. Choose a suitable VPS server. US VPS servers are widely distributed, located on both the East and West Coasts and in the Midwest. For mainland China access, connections from the East Coast (such as Los Angeles, San Francisco, and Dallas) are generally preferred. Some areas have more direct CN2 dedicated line access.
3. Configure the MTU value to avoid packet fragmentation. An inappropriate MTU setting can increase packet fragmentation and reduce network efficiency. It's recommended to adjust the MTU value based on the actual link, generally setting it to 1400-1460 bytes, to avoid additional latency caused by packet fragmentation.
4. Use HTTP/2 and TCP optimization technologies. Enabling HTTP/2 multiplexing can reduce the number of request connections and improve load times. Expanding the TCP window and optimizing the congestion control algorithm can also improve transmission efficiency.
5. Continuously monitor and dynamically adjust. Cross-border network conditions fluctuate frequently. It's recommended to establish a monitoring platform to track latency, packet loss, and bandwidth utilization in real time, and dynamically switch routes or adjust configurations using automated policies.
High latency when accessing US VPSs from mainland China is a common challenge for cross-border businesses. However, by selecting high-quality routes, deploying a CDN, using intelligent routing, multi-line BGP strategies, and rational architecture design, access speed and stability can be significantly improved. Different business scenarios should flexibly apply various optimization solutions based on budget and actual needs. Technical details and monitoring must not be neglected; continuous optimization is essential to maintaining efficient and stable cross-border access.
