How to Read China's Carrier AS Numbers: AS4134, AS4809, AS23764, AS4837, AS9929, AS58453, and AS58807 Explained

“CN2 GIA,” “premium China routing,” “three-network optimized.” You’ve seen the labels, and if you’ve been in this market for long you’ve probably bought at least one server whose real route didn’t match its label.

The way to cut through it is to stop reading labels and start reading AS numbers. An autonomous system is a routing domain identified by an AS number; many end-user networks operate within a provider’s AS rather than having their own. China’s three state carriers each run several of them, split between cheap standard backbones and premium networks. Traceroute and BGP data provide evidence about the path, but they cannot certify the commercial product you bought.

This guide explains the Chinese carrier AS numbers that matter for foreign-hosted servers, how to identify them in a traceroute, and how to verify a provider’s route claims in both directions.

Why AS numbers tell you more than route names

Route names are marketing; AS numbers are routing. When a provider says it has CN2 GIA, it’s describing a commercial product, and products can be sold on, mixed, or used for only part of the path. An AS-aware traceroute maps responding interface IPs to origin ASes. That mapping can differ from the actual forwarding path because of hidden hops, MPLS, third-party interface addresses, and asymmetric ICMP replies.

This matters because each Chinese carrier runs a congested standard network and a premium network side by side. Both get you into China, and both can show up for the same destination at different times or in different directions. The difference between them at evening peak can be the difference between 2% and 20% packet loss.

The other reason is that names change. China Telecom’s premium international product is now called CTGNet, China Unicom sells CUP, and China Mobile sells CMIN2, but older names like CN2 GIA and “9929” still circulate. The AS numbers have stayed stable through the rebranding.

China Telecom: AS4134, AS4809, and AS23764

AS4134 is ChinaNet, China Telecom’s main domestic backbone, often called “163” after its original network name. It carries most ordinary China Telecom traffic, including standard international transit. It’s enormous and heavily loaded, and at evening peak the international links into it are where much of the loss on cheap routes happens. In traceroutes, its routers commonly appear in the 202.97.x.x range.

AS4809 is CN2, China Telecom’s Next Carrying Network, a separate premium backbone built for business and higher-quality traffic. Its routers typically show up as 59.43.x.x hops. The distinction between the two classic CN2 products comes down to where AS4809 appears. With CN2 GT, traffic enters through the 163 network at the international gateway and only uses CN2 for part of the path, so you’ll see 202.97 hops mixed in. CN2 GIA is associated with premium CN2 delivery, but access networks and unresponsive routers mean a real traceroute need not contain only 59.43 addresses.

AS23764 is China Telecom Global’s international network, CTGNet, which carries the premium product outside mainland China and connects to AS4809 at the border. When a provider describes “CTGNet (formerly CN2 GIA),” AS23764 and AS4809 together are what you should expect to see, rather than treating a single hop prefix as a pass/fail rule. China Telecom’s official Global Internet Access page describes access through ChinaNet (AS4134) and CN2 (AS4809), showing why the commercial service name alone does not establish a single AS path.

China Unicom: AS4837, AS9929, and AS10099

AS4837 is China Unicom’s main backbone, known as “169.” Like AS4134 on the Telecom side, it carries most standard Unicom traffic and gets congested at peak, though Unicom’s international capacity has historically held up better than Telecom’s standard route in some regions. Its routers often appear in the 219.158.x.x range.

AS9929 is the China Unicom Industrial Internet backbone, previously known as CNCNET and nicknamed the “A network.” It’s Unicom’s premium network, carrying far less consumer traffic and staying cleaner at peak. Hops in the 218.105.x.x and 210.51.x.x ranges are common signs you’re on it.

AS10099 is China Unicom Global, the carrier’s international arm. Unicom’s premium product, CUP, typically pairs AS10099 outside China with AS9929 inside it, but domestic access hops and incomplete responses mean the exact visible sequence varies. Confirm the purchased service with the provider as well as checking measured performance.

China Mobile: AS9808, AS58453, and AS58807

AS9808 is CMNET, China Mobile’s domestic network. You’ll see it at the China end of most China Mobile paths regardless of which international route was used, often in the 221.183.x.x and 221.176.x.x ranges.

AS58453 is China Mobile International’s standard network, CMI. It’s the default for much of China Mobile’s international traffic, and it performs reasonably well in parts of Asia but varies a lot depending on where it hands off and how loaded it is. Hops in 223.120.x.x are a common sign.

AS58807 is CMIN2, China Mobile International’s premium network. It’s the China Mobile equivalent of CTGNet or CUP, carrying traffic on a separate, less congested path. Seeing AS58807 rather than AS58453 on the international leg is what separates the premium route from the standard one.

A quick reference table

Carrier	Standard network	Premium network	International arm	Common hop hints
China Telecom	AS4134 (163)	AS4809 (CN2)	AS23764 (CTGNet)	202.97 = 163, 59.43 = CN2
China Unicom	AS4837 (169)	AS9929 (CUII)	AS10099 (CUG)	219.158 = 169, 218.105 = 9929
China Mobile	AS9808 (CMNET) domestic	AS58807 (CMIN2)	AS58453 (CMI) standard	223.120 = CMI, 221.183 = CMNET

Treat the hop prefixes as hints rather than proof. Address assignments change, and some routers answer from interfaces you wouldn’t expect. A BGP lookup identifies the origin AS of the prefix containing the responding address; it still does not prove the router’s complete forwarding path or the purchased service tier.

How to read a traceroute for carrier AS numbers

Use a traceroute tool that shows AS numbers alongside each hop. On Linux, mtr -z (or mtr --aslookup) adds an AS column, and traceroute -A does the same on many systems. Run it toward an address on the carrier you care about, such as a China Telecom IP in Shanghai or a China Mobile IP in Guangzhou.

Work through the path from your server outward. The first few hops belong to your provider and its upstreams. Watch for the point where a Chinese carrier AS first appears, which tells you where traffic entered that carrier’s network and whether it entered on the standard or premium side.

Then check consistency. A route that shows AS4809 throughout, with no AS4134 hops, is behaving like a premium Telecom path. A route where AS4134 appears at the border and AS4809 only later is closer to CN2 GT. A route showing only AS4134 is standard ChinaNet, whatever the plan page says.

For any hop you’re unsure about, look up the address on bgp.tools or Hurricane Electric’s BGP toolkit, which show the originating AS and its announced prefixes. PeeringDB is useful for checking which networks a provider actually interconnects with.

Check both directions

Here’s the part most quick checks miss. A traceroute from your server shows one direction only: server to China. That’s the direction carrying the bulk of the data when a user loads a page or downloads a file, which is why it’s the one providers like to show. Internet routing is frequently asymmetric, though, so the other direction, China to your server, can use a completely different network.

That inbound direction matters more than it looks. It carries every request, every upload, every game input, and every TCP acknowledgment, and loss on the acknowledgments throttles throughput on the outbound side too. Some providers buy premium routing in one direction only, because it’s cheaper, and leave the other on the standard network.

To check it, you need a traceroute from inside China to your server. China-based network testing services, or a test machine on each carrier, let you run that. A route that’s premium in both directions is what you’re actually after, and it’s worth asking any provider directly whether its routing is premium both ways. Our list of questions to ask about CTGNet and CN2 GIA claims covers this in more detail.

Common patterns and what they mean

You see AS4809 outbound but AS4134 inbound. That suggests an asymmetric path, but it does not prove the provider’s purchasing arrangements. Confirm the full path and ask the provider to explain it. Pages may still load reasonably, but uploads, interactive traffic, and anything sensitive to acknowledgment loss will suffer at peak.

A route is premium to China Telecom but generic to Unicom and Mobile. That’s a single-carrier optimization, common with providers that sell “CN2 GIA” and nothing else. Users on Unicom or Mobile, which together make up a large share of Chinese internet users, get the standard path.

The AS path changes between tests. Some providers route dynamically or have multiple upstreams, so you might get CN2 at noon and 163 at night. Run tests at different times, especially evening peak in China, before drawing conclusions.

You see a Hong Kong or Japanese carrier between your provider and the Chinese network. That’s normal for many routes and not necessarily bad, but it adds a handoff. Premium paths typically connect more directly.

How to verify a provider’s claims before you buy

Start with the provider’s Looking Glass. Run a traceroute from their server to a test IP on each of China Telecom, China Unicom, and China Mobile, and read the AS numbers. Our own Looking Glasses for Tokyo and Singapore support ping, traceroute, and BGP lookups for exactly this.

Check the BGP side next. Inspect BGP paths from several vantage points and the provider’s looking glass. One collector shows only the route selected at that vantage point; it does not enumerate every upstream or establish a direct commercial relationship.

Then test the China-to-server direction, ideally at evening peak, and on all three carriers. Remember that any single result is a snapshot. A good traceroute at 10 a.m. doesn’t promise the same path at 9 p.m., so look for consistency across several tests rather than one perfect run.

Wrapping up

The Chinese carrier AS numbers to know are AS4134 and AS4809 for China Telecom’s standard and CN2 networks, with AS23764 on the international side; AS4837 and AS9929 for China Unicom’s standard and premium networks, with AS10099 internationally; and AS58453 and AS58807 for China Mobile’s standard and premium international routes, with AS9808 at home. Seeing the premium ones in both directions, on all three carriers, is what “premium China routing” should actually mean.

Read traceroutes for AS numbers, not labels, check both directions, and test at peak. That’s how you find out what you’re really buying.

Thanks for reading! If you’d rather verify than trust, Riven Cloud runs KVM VPS in Tokyo and Singapore on CTGNet (AS23764/AS4809), CUP (AS9929/AS10099), and CMIN2 (AS58807), with a public Looking Glass in each location so you can check the AS path to every carrier before you order.

Want to see the path for your own users? Compare plans or contact our team with questions.

Frequently asked questions about China carrier AS numbers

What is AS4809?

AS4809 is China Telecom’s CN2 network, its premium backbone. AS4809 is associated with CN2 delivery. CN2 GIA and CTGNet are related commercial routing terms, but AS4809 appearing in a traceroute does not by itself certify either service or require every visible hop to be in that AS.

What’s the difference between AS4134 and AS4809?

AS4134 is ChinaNet, China Telecom’s standard, heavily loaded backbone. AS4809 is CN2, its separate premium network with lower congestion. Both reach the same users, but AS4809 typically holds up far better at evening peak.

What is AS9929?

AS9929 is China Unicom’s Industrial Internet backbone, formerly CNCNET, used as its premium network. It pairs with AS10099 internationally to form the CUP product.

What’s the difference between AS58453 and AS58807?

Both belong to China Mobile International. AS58453, CMI, is the standard international network, while AS58807, CMIN2, is the premium network with a separate, less congested path.

How do I see AS numbers in a traceroute?

Use mtr -z or mtr --aslookup on Linux, or traceroute -A where supported. For individual hops, look up the address on bgp.tools or bgp.he.net to confirm which AS it belongs to.

Why does my traceroute look premium but users still see slow speeds?

The path from China to your server may use a different, standard network, and loss in that direction slows everything down. Routing is often asymmetric, so test from inside China to your server as well, ideally at evening peak, on all three carriers.