Mainland Network Circuits

June 19, 2025 · 3 min read · Page View:

The 163 network backbone circuit of China Telecom

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The performance and reliability of internet connectivity to and from mainland China are determined by a complex web of different network circuits, each with its own characteristics.

We will explore the crucial differences between the standard public network backbones, like the workhorse 163 network, and premium, optimized lines like CN2. We’ll also explain what dedicated networks such as IPLC are and why they offer a completely different level of performance and privacy. By the end of this article, you’ll have a clear framework for understanding these circuits, helping you make more informed decisions whether you’re choosing a hosting provider, diagnosing network issues, or are simply curious about how the internet infrastructure in mainland China operates.

You can check every circuit’s info here: https://bgp.he.net/^[1] eg. https://bgp.he.net/AS4809#_graph4^[2]

Public Network #

International export: The international export is the last port of the internet in China when the traffic is going to the overseas. Mainly located in Beijing, Shanghai and Guangzhou. Many ISP will not directly connect their circuits to the international export, there exists some detours situation^[3]. And there are also some foreign circuits, this article will only cover mainland circuits.

China Telecom^[4] #

• 163: AS4134. The 163 network is the backbone of the internet in China. And mainly used by China Telecom. The backbone node is started with 202.97. There is basically no performance bottleneck when accessing each other within the 163 network in China. Congestion only occurs at the international export.
• CN2(CNCN): AS4809. China telecom next carrier network, which is the backbone of the internet in China(Public network), which is more advanced than the old 163 network. The backbone node is started with 59.43.
  • CN2GT: CN2 Global Transit, cheaper but congested, in CN2 GT product in the city → province → international export section is 163 network, the international export → overseas access point section is CN2 network, the return is the same.
  • CN2GIA: CN2 Global Internet Access, expensive but less congested.(eg. Bandwagonhost has the most stable and cheapest CN2GIA line, but it is the key examined object of domestic.) GIA the whole network is CN2 network.
• CTGNet: AS23764. Responsed by China Telecom Global Limited, mainly for the overseas business.
• CN2-DCI: The third generation of CN2, constructed since 2015. Mainly for business.

China Unicom^[5] #

• 169: AS4837. The 169 network is the backbone of the internet in China. And mainly used by China Unicom. Started with 219.158.
• A Net: AS 9929, CUII, Also known as the former China Netcom Internet (CNCNET). The AS number of China Unicom’s A network backbone is 9929. It was built by the China Netcom, and after the merger of China Netcom and China Unicom, so the A network was available. Now the users are less and mainly aims for the government(Actually you will seldom see it, at least I have never seen it). Started with 218.105.*.* or 210.*.*.*.
• CUG: AS10099. Provides the differentiated access to the mainland direction. Mainly CUG（AS10099 -> AS4837） and CU Premium AS10099 -> AS9929 -> AS4837.

The China Unicom is a special case unlike the Telecom:

• Mainland: 169 network (AS4837), or A network (AS9929)
• Overseas: 169 network (AS4837), or CUG (AS10099)

China Mobile^[6] #

• CMNET: AS9808. The AS9808 is the backbone of the internet in China. And mainly used by China Mobile. The PCCW line is currently among the lines between China and Hong Kong, China or those from China to other regions in Southeast Asia where transshipment in Hong Kong, China is required. It is the line with the best quality in China except for the pure CN2 GIA line.
• AS24059. The AS24059 is used for the IP private network, which is used to carry the soft switch voice/signaling, network management, telecommunication operation support system, self-owned business, etc.
• CMI: AS58453. Overseas Network.
• CMIN2: AS58807. Overseas Network.(Optimized Network)

Others #

• Educational Network
• China Science and Technology Network
• Private Broadband.

Dedicated Network #

IPLC: International Private Leased Circuit, which is the international dedicated line.

But for many service suppliers, it is just the intranet of Alibaba(深港means Alicloud shenzhen – Alicloud HK), which usually purchase multiple end to end IPLC lines to connect the every data center. Then it has two pros:

1. The bandwidth in IPLC is dedicated, which is more stable than public network.(The decicated line is normally described the physical line, the most traffic in Submarine optical cable is the public network traffic and small part is the IPLC traffic.)
2. The traffic when transiting, it will not go through the specific examination.

IEPL: International Ethernet Private Line, which is the enhanced version of IPLC. It is a dedicated management bandwidth service from end to end.