From a network perspective: Instability of Hong Kong servers CN2 and suggestions for improving routing strategies

The unstable CN2 link of Hong Kong servers is sensitive in scenarios requiring cross-border access and low latency. This article analyzes the typical manifestations and root causes of CN2 instability from a networking perspective, and proposes actionable routing strategies and operational improvement suggestions aimed at helping engineering teams enhance availability and user experience.

CN2 instability usually manifests as delayed fluctuations, an increased packet loss rate, and frequent path changes. Causes include cross-border export congestion, poor inter-ISP connectivity, slow BGP convergence, link maintenance, or strategic traffic engineering, and it may also be affected by DDoS or incorrect routing configurations.

At the routing level, issues are mostly related to BGP policies, AS path selection, and MED and local priority settings. Incorrect prefix announcement or unreasonable AS_PATH operations cause traffic to take a detour, increasing hops and jitter ； At the same time, the lack of proper filtering introduces suboptimal paths.

It is recommended to establish a continuous multi-point monitoring system, including Ping and Traceroute based on latitude and longitude, as well as traffic sampling (NetFlow/sFlow). By combining BGP routing views with an analysis of historical routing changes, it is possible to quickly determine whether the path change is caused by link congestion, ISP failures, or policies.

Prioritize multihoming and BGP redundancy, select upstream providers with stable quality, and configure appropriate LOCAL settings_PREF and COMMUNITY are used to direct inbound traffic. Through AS_PATH prepending and Selective Announce optimize outbound paths to reduce uncontrollable detours.

Achieve intelligent traffic distribution using Anycast or SD-WAN, and configure more granular routing policies and QoS markings for important prefixes ； At the same time, security measures such as RPKI/ROA are enabled to prevent instability caused by misannouncements and route hijacking.

Choose upstream and peer partners in Hong Kong with good connectivity, giving priority to evaluating interconnection latency, packet loss rates, and historical failure records. When signing an SLA, focus on convergence time and fault response procedures, and require visualized routing and link status data for quick decision-making.

In summary, addressing the instability of Hong Kong server CN2 from a networking perspective requires monitoring as a foundation, BGP and multiple hosts as core components, along with the use of Anycast/SD-WAN, traffic engineering, and security verification. It is recommended to implement monitoring deployment, routing strategy optimization, upstream diversification, and SLA negotiations in priority order to achieve measurable improvements in stability.