CN2 GIA vs CN2 GT vs BGP: A China Route Buyer's Guide

If your visitors are in mainland China, the network line behind your server often matters more than CPU or RAM. Providers in Hong Kong and the wider Asia-Pacific region advertise many labels, and the difference between CN2 GIA vs CN2 GT and ordinary BGP or 163 lines shows up most clearly in the evening, when Chinese networks are busiest. This guide explains what each line is, how it behaves, how to test it before you buy, and how to choose.

Two China Telecom Backbones: AS4134 and AS4809

China Telecom runs two separate backbones. ChinaNet (AS4134), often called the 163 network, carries most consumer traffic. Its international gateways are heavily used, so cross-border traffic can see higher latency and packet loss at peak times. CN2 (AS4809), the "next carrier network", is a premium backbone with lower utilisation, more stable latency and a higher price.

You can usually recognise them in a traceroute: hops in 202.97.x.x belong to the 163 backbone, while hops in 59.43.x.x belong to CN2.

The Main Line Types Explained

CN2 GIA

CN2 GIA (Global Internet Access) keeps traffic on AS4809 in both directions, from the overseas data center to the user's province. It is the most stable China Telecom option at evening peak and also the most expensive bandwidth.

CN2 GT

CN2 GT (Global Transit) uses CN2 for the international section but hands traffic to the 163 backbone inside China. It is clearly better than plain 163 at most times, but because part of the path is shared with consumer traffic, latency can rise in busy hours.

Standard BGP / 163

Ordinary international BGP bandwidth reaches China Telecom users via 163. It is affordable and fine during the day, but evening congestion often brings higher latency and noticeable packet loss for China users.

CMI and China Unicom 9929 / 4837

China Mobile users are often best served by CMI (China Mobile International) routes. For China Unicom, AS9929 is the premium network, while AS4837 (the 169 backbone) is the standard network that usually performs reasonably well. A good "three-network" route chooses the right path for Telecom, Unicom and Mobile users.

Why the Return Route Matters

Internet routing is asymmetric: the path from China to your server (outbound) and from your server back to China (the return route) are often different. Most data flows from server to user, such as web pages, downloads, video and game updates, so the return route largely decides what your visitors experience. A server may advertise CN2 but return traffic to Unicom or Mobile users over ordinary routes, or reach Telecom users through 163 in the evening. Our guide How to Test a Server's Return Route shows how to check this for all three carriers.

How to Test Before You Buy

Ask for a test IP and run these from a computer in mainland China, ideally once in the afternoon and again between 20:00 and 23:00 Beijing time:

ping -c 100 203.0.113.10
mtr -rwc 50 203.0.113.10
nexttrace 203.0.113.10
besttrace -q 1 203.0.113.10

• ping: look at average latency and the spread between the lowest and highest values, not just the minimum.
• mtr: 50 cycles reveal packet loss and on which hop it starts. Loss only on a middle hop that does not continue to the end is usually harmless.
• nexttrace / besttrace: show the ASN and location of each hop, so you can see whether traffic uses 59.43.x.x (CN2) or 202.97.x.x (163).

To check the return route, log in to the test server and trace back to a China Telecom, Unicom and Mobile address in your users' province (replace the example with a real one):

mtr -rwc 50 198.51.100.20
nexttrace 198.51.100.20

For more on running these tools, see Speed Test and Traceroute Guide.

Use Cases and How to Choose

• Websites and e-commerce for China users: CN2 GT is often enough for content sites; choose CN2 GIA when checkout speed and evening stability matter.
• Game acceleration and real-time apps: jitter and loss hurt more than raw latency, so CN2 GIA or a well-tuned three-network route is the safer choice.
• API relays and cross-border office: pick by where your staff connect from; mixed teams benefit from a route optimised for all three carriers.
• Global or non-China audiences: standard BGP is cost-effective and usually all you need.

1. Identify which carriers your users are on and when they are online.
2. If most traffic is in the Chinese evening, budget for CN2 GIA or a premium three-network route.
3. If the budget is tight, start with CN2 GT or BGP and upgrade after measuring real traffic.
4. Choose the location by audience as well as route.

At IMIDC, Hong Kong, Russia and US (Los Angeles) servers have CN2 routes to China, Japan servers use CN2-optimised routes, Korea servers run on the KT network, and Taiwan servers offer native Taiwan IPs. Other locations are best suited to audiences in their own regions, so test first if China access matters.

FAQ

Is CN2 GIA always faster than CN2 GT?

Not always during quiet hours, when both can perform similarly. The difference is mainly stability at evening peak and during congestion.

Why is my ping fine but the website still slow in the evening?

Ping is small and may take a different path. Check packet loss with mtr and test the return route, since page data travels from server to user.

Do I need CN2 if my users are outside China?

Usually not. CN2 mainly improves access from mainland China; for other audiences, standard BGP lines in the right location are generally sufficient.

How can I tell which line a server really uses?

Run nexttrace or besttrace in both directions and look at the ASN of each hop: AS4809 and 59.43.x.x indicate CN2, AS4134 and 202.97.x.x indicate 163.

Need help reading your test results or choosing a location? Open a support ticket and the IMIDC 24/7 team will review your routes and recommend a suitable server.