Guide for Troubleshooting Large Delay and Route Overlap in Cloud Connected Network (CCN)
In the architecture of enterprise hybrid cloud and multi-branch networking,
Cloud Connect Network (CCN)
It is the core weapon to realize the efficient access of offline gateway devices (SAG) to Alibaba Cloud, and complete enterprise remote networking and plug-and-play interconnection. With seamless integration with Enterprise Forwarding Router (TR) and Cloud Enterprise Network (CEN), CCN helps many enterprises build agile networks covering the whole country and even the world.
However, in the actual operation and maintenance and SEO technical support work, we often receive feedback from branches:
"Today's system access is extremely slow, and cross-region access to the database has timed out"
, or
"The two branches below the line cannot cut each other, and the business is directly paralyzed"
.
As an SEO website optimizer who pays attention to site stability and full link experience, I know very well:
Any jitter, latency spike, or routing conflict on the network base is reflected in the front end of page load timeout, TTFB (first byte response time) deterioration, search engine crawl failure, or even service interruption.
This article will take the perspective of real front-line investigation, in-depth analysis of Aliyun CCN in off-site networking
Large delay
with
route overlap
The root causes of the two core pain points, and provide a set of troubleshooting and optimization strategies that can be landed.
1. why is there a large delay in CCN remote networking?
In an ideal state, CCN will provide low-latency and high-quality transmission to all branches through the backbone network of Alibaba Cloud. If there is a sudden delay surge or packet loss, it is usually caused by the following four reasons:
1. Physical path deflection (cross-regional not the best backbone)
CCN supports local access by default, but if the enterprise does not correctly configure cross-region interconnection (such as cross-region connection of CEN), or
Access point (POP point) selection error
:
The branch SAG equipment located in Chengdu is connected to the CCN access point in Beijing due to the DNS or routing problem of the local operator;
When this branch tries to access the business of VPC on Guangzhou cloud, the traffic path becomes Chengdu-> Beijing POP -> Guangzhou VPC, bypassing more than half of China, and the delay naturally increases exponentially.
2. Line bandwidth speed limit or sudden congestion
The cross-region bandwidth of CCN and CEN usually requires the purchase of bandwidth packages on the forwarding router (TR) or cross-region connection (or use the per-traffic/per-bandwidth billing mode).
Business traffic burst: The offline branch suddenly initiates large file transmission, full backup or video conference, resulting in the upper limit of cross-regional bandwidth (100 full load), triggering the system's speed limit and packet loss mechanism.
Degradation of Arrears and Speed Limit: When some enterprises adopt the pay-as-you-go or bandwidth package automatic renewal mode, if the finance fails to follow up in time, it may lead to insufficient account quota, triggering bandwidth degradation of cloud resources or even service suspension. Therefore, in the daily network operation
In the maintenance and infrastructure management, ensuring that the financial early warning mechanism is smooth and the Alibaba Cloud account recharge is completed on a regular basis to ensure sufficient funds, which is the basic prerequisite to prevent network bandwidth from being limited by no early warning speed and to ensure high business availability without interruption.
3. SAG Hardware and Local Egress Link Bottleneck
The problem does not necessarily lie in the Alibaba Cloud cloud, but may also lie in the "last mile":
The performance of SAG devices is tight: the hardware CPU is full, and too many complex security policies or flow control rules are enabled, resulting in a surge in data packet encryption and decryption time.
Poor local broadband quality: The local broadband bound by SAG (such as ordinary home broadband or wireless 4G/5G) itself has packet loss, fiber attenuation, or operator backbone network jitter.
2. routing overlap: the man behind the network "mess"
"Route Overlap/Conflict" is often more deadly than simply "slow. It can cause some branches to suddenly fail to communicate with each other, or traffic to be dropped by mistake (black hole).
In CCN hybrid networking, route overlap usually occurs in the following scenarios:
1. The offline network segment (CIDR) planning is not standardized
Enterprises in the initial deployment did not do a unified IP address planning. For example:
The local LAN segment of the Shanghai branch is 192.168.1.0/24;
The local LAN segment of Shenzhen branch is also 192.168.1.0/24;
The two branches simultaneously bind and learn the same CCN through their respective SAGs.
At this point, CCN receives a trip
192.168.1.X
A routing conflict occurs when the traffic is. The cloud cannot determine whether the data packet should be delivered to Shanghai or Shenzhen, causing communication interruption or "random drop".
2. Dynamic routing (BGP/OSPF) release out of control
When the BGP or OSPF dynamic routing protocol runs between the SAG and the offline enterprise core switch, if
Lack of route filtering (Route Map / Prefix List)
:
The offline switch mistakenly released a 0.0.0.0/0 default route or WAN segment to SAG and further synchronized to CCN cloud;
This causes the VPC traffic on the CCN to be incorrectly directed to an unauthorized offline router, resulting in a routing loop or traffic black hole.
3. five-step combat method for troubleshooting "large delay" and "route overlap"
When receiving an alarm that the network is slow or disconnected, perform progressive troubleshooting according to the following standardized process:
[Step 1] Confirm the topology and traffic path (clear SAG -> POP point-> TR -> VPC path)
│
▼
[Step 2] Check the routing table (troubleshoot overlapping and black hole routes in the CCN/TR/VPC routing table)
│
▼
[Step 3] Test network delay and packet loss rate
(using Ping, MTR, Tracert segment positioning)
│
▼
[Step 4] Check the status of cloud resources and bandwidth utilization (confirm whether the bandwidth is full or the account is in arrears)
│
▼
[Step 5] Check SAG hardware status and local export (CPU, memory, optical link and carrier quality)
Step 1: Identify traffic paths and access points
Log on to the Alibaba Cloud console to view the connection status of the Smart Access Gateway (SAG) and CCN:
Check whether the Alibaba Cloud POP point connected to SAG is the physical node closest to the local area.
If cross-province access is found, you can try to restart the SAG connection or contact Alibaba Cloud technical support to adjust the access point policy.
2. Step 2: In-depth investigation of routing tables (location route overlap)
Examine the routing table at three locations in turn:
CCN routing table: Check whether the same CIDR mask exists in the learned offline network segment.
Forwarding Router (TR) route table: Check whether there is a priority override for routes conducted by cross-region connections and VPCs.
VPC route table: Check whether the custom route pointing to the CCN is correct.
💡Troubleshooting Tips: If multiple branch network segments overlap, Alibaba Cloud CCN matches finer subnets (long prefix matching) first by default. If the network segments are completely consistent, you must configure NAT gateway/mapping rules on SAG or TR, or reconstruct and divide the offline network segments.
3. Step 3: Segmentation using MTR tools for link testing
Don't just ping the domain name in the terminal, use
mtr
or
traceroute
Segmented test:
Bash
# The private IP address of the VPC on the MTR cloud directly on the offline branch host
mtr -n --report --report-cycles=100 10.0.1.100
Analyze the number of hops: If the delay is high before entering the Alibaba Cloud backbone network (usually a specific intranet IP segment), the problem is the local operator or SAG exit.
Analysis of packet loss: If more than 50% of continuous packet loss occurs suddenly in a hop in the middle, it indicates that the backbone network or cross-regional connection bandwidth has a congestion speed limit.
4. Step 4: Check bandwidth utilization and account status
Go to the CloudMonitor (cloud monitoring) to view the real-time bandwidth curve of cross-region connection and CCN:
If the bandwidth utilization is above 90% for a long time, it indicates that the service growth has exceeded the existing bandwidth package and needs to be expanded in time.
Check the cost status of cloud resources to prevent resource degradation caused by automatic renewal failure. Recharge your Alibaba Cloud account in a timely manner and set up a balance alert to provide a solid financial guarantee for the continuous and stable operation of your business.
5. Step 5: Check the SAG device and local link
Login to SAG
Console or Local Management Web Interface:
Check whether the CPU and memory usage of the device are normal.
Check the packet loss and optical power of the WAN port to eliminate the problems of local network cable aging, wireless signal interference or carrier fiber attenuation.
4. Solution and Optimization
In view of the above investigation results, the following countermeasures are recommended:
Problem phenomenon
The core reason
The best solution
route overlap
Offline branch CIDR segment conflict
Large cross-geographical delay
No backbone network/no TR
Bandwidth runs full frequently
Business Burst Traffic/No Flow Control
occasional service interruption
Account Arrears/Bills Abnormal
Improve the operation and maintenance financial warning, and regularly complete the recharge of Aliyun account to ensure smooth charging and renewal by volume.
5. the Linkage Thinking of SEO and Technical Operation and Maintenance
As SEO optimizer, we should not only care about the front-end TDK configuration, content quality and external chain construction, but also care about
The overall network architecture behind the website
.
Especially in scenarios involving cross-region multi-data center deployment and hybrid cloud architecture (for example, the front-end web page is deployed on the cloud, and the back-end core data/ERP is stored online in the private cloud):
CCN delay directly affects page loading: if the front end on the cloud needs to frequently call offline private cloud data through CCN when rendering pages, CCN's high delay will directly lengthen TTFB (first byte response time), thus reducing Baidu and Google's rating of the page.
Overlapping routes may lead to crawler crawling timeout: if DNS resolution or internal microservices cause some nodes to fail due to routing conflicts, search engine spiders may encounter 504 Gateway Timeout when crawling dynamically rendered content, causing a blow to website inclusion.
Summary
Alibaba Cloud Cloud Connected Network (CCN) has brought great convenience for enterprises to network in different places, but network troubleshooting is a system engineering that "affects the whole body.
Facing the problem of large delay and overlapping routing in remote networking, we must
Take the routing table as the starting point, based on the segmented link test.
We should not only do a good job in offline IP specification planning and hardware monitoring, but also ensure the continuous stability of cloud bandwidth and account funds. Only by creating a zero-conflict, low-latency, high-availability hybrid cloud network can provide the most solid guarantee for the SEO performance of the upper business and website.
