Review Of The CN2 To The US Route Via Singapore And Feasible Technical Solutions For Improving The Link

Reasons Usually from various sources: One is from upstream or backbone operators BGP Path Selection Preferences cause the originally direct route to be changed by ads or policies ； Secondly, there are failures or congestion in the intermediate links. To maintain connectivity, operators choose alternative paths, resulting in traffic being routed through Singapore ； Third, there is a lack of equivalent points (IX) or peering strategies between the two parties, forcing traffic to take a longer route via IP transit ； Fourth is incorrect configuration, such as BGP community The local-pref or MED is misconfigured.

In this case, during a link maintenance task, the operator activated the backup MPLS/TE policy. Combined with the upstream BGP policy, this resulted in traffic originating from China and destined for the United States being routed preferentially through Singapore as an exit point, creating a clear detour.

The most direct is Increased latency It causes an increase in jitter, affecting the experience of voice, video, and interactive services ； Next is the decrease in throughput due to an increase in packet loss and more retransmissions ； Furthermore, asymmetric upstream and downstream traffic on the link can affect TCP performance and security policies (such as geolocation-based access control), as well as increase bandwidth costs and SLA risks.

E-commerce, low-latency financial transactions, and real-time audio and video services are particularly sensitive to such detours, which can directly cause users to lose connection, orders to fail, or an increase in QoS complaints.

The first step is to use traceroute/mtr Confirm path hop count and nodes ； Combine BGP routing table (show ip bgp) Check path attributes (AS_PATH, local-pref, MED, community) ； Analyze traffic flow distribution using NetFlow/sFlow or TSAMP ； Deploy active probing (ping, latency probes) and passive monitoring (SNMP, ifDescr) on suspicious links to identify sources of packet loss/jitter.

Use BGP looking glasses and routing monitoring platforms (such as RouteViews, RIPE RIS) to compare routing advertisements from different observation points, and check whether ISP announcements or maintenance window logs are related. If MPLS or TE is used, employ SRv6/Segment Routing tools to view the LSDB and LSP status.

Option A: Optimizing BGP policies — through adjustments local-pref Use BGP communities or introduce more direct peerings/IXPs to achieve proximity-based egress and load balancing. Plan B: Deploy SD-WAN or smart routers to route application traffic to low-latency paths and enable automatic link switching.

Option C: Introduce multi-operator redundancy and proactive health checking (BFD/ICMP), combined with MPLS-TE or FRR for fast rerouting ； Plan D: Use Segment Routing or SRv6 for explicit routing to ensure that critical services take the designated paths, avoiding being overwritten by upstream policies.

When choosing a solution, it is necessary to weigh costs (bandwidth and interconnection fees), operational complexity, and business urgency. Recommended priorities: In the short term, use BGP adjustments and SD-WAN strategies for rapid recovery; in the long term, advance the transformation to multi-link and SR architectures.

At the deployment level, it is recommended to establish a multi-point proactive detection network (from key POPs to target countries), with sampling latency/packet loss measured per minute ； Enable BFD and fast convergence mechanisms on the router, and establish a rollback process for BGP policy changes. Introduce real-time alerts (delay threshold, packet loss threshold, path anomalies) and establish SOPs in the NOC.

Monitoring items include: End-to-end RTT, packet loss rate per hop, BGP update frequency, number of path changes, traffic distribution, and link utilization. Combine automated scripts to notify in case of exceptions and trigger predefined traffic switching strategies.