Connect to ChinaExplainer

Internet exchange points and the way to China

An exchange lets networks hand traffic to each other directly. It reaches the networks present there, not the ones inside mainland China.

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What an internet exchange point is

An internet exchange point (IXP) is a shared switching platform, usually in a data center, where networks connect once and then exchange traffic directly with any other member that agrees to peer. That direct exchange is called peering.

Peering keeps traffic between two networks short and local. It reaches only the networks present at the exchange and their customers, so most networks also buy IP transit for everything else.

Most exchanges are a switched fabric. Each member connects a port, the fabric forwards frames between members that have agreed to peer, and a route server can distribute routes so nobody has to configure every neighbor by hand. The route server shares routing information; the traffic still crosses the fabric between the two members.

An exchange is not the same thing as a data center or a point of presence. The data center rents space, power and cross-connects, the exchange runs the interconnection fabric inside it, and a PoP is where a provider hands over traffic. One building can host all three, but they are different services with different contracts.

AS numbers BGP Point of presence

Peering at an exchange and IP transit

How peering at an exchange compares with IP transit
Aspect	Peering at an exchange	IP transit
Reaches	The networks at the exchange that agree to peer, and their customers	Every destination on the internet, through the provider's routes
Arrangement	Agreed network by network	One contract with the transit provider
Typical use	Local and regional traffic between networks that meet there	Everything peering does not cover
Cost	A port fee plus a cross-connect; peering itself is often settlement-free but not always	A recurring fee for capacity and commit
Responsibility	You set your own filters, policies and capacity; each network is responsible for its own side	The provider's routing and support cover the path to the internet

How exchanges are organized, by region

Americas

Many countries run national or community exchanges in their main cities, often supported by the local internet community or academic networks.
They keep domestic traffic in the country; traffic to other continents still travels on transit or private capacity.
Route servers and looking glasses are common, so a prospective member can see who is present before taking a port.

Europe

Large exchanges in the main interconnection hubs connect networks from many countries, run by member associations or as companies.
Port fees are often low and settlement-free peering between networks of similar size is common, so many international networks meet there.

Asia

Regional hubs host exchanges where networks from across Asia meet, and many international networks connect there.
Capacity between countries is costly, so networks tend to peer where traffic concentrates, at regional hubs and the exchanges inside them.

Mainland China

Domestic networks interconnect at national backbone interconnection points designated by MIIT, and at newer internet exchange centers approved by MIIT.
International traffic enters mainland China on a Chinese carrier backbone, through designated international gateways, not through an open exchange.
A domestic exchange center is not an international gateway. Ask which gateway your traffic will use, not only which exchange a network is present at.

What an exchange does for traffic to China

Peering at an exchange outside mainland China reaches the networks present there. Reaching users on networks inside the mainland still means carrying traffic onto a Chinese carrier backbone, through IP transit, premium routing or a private line.

Exchanges and China connectivity cover different traffic: peer for regional traffic, and choose a China route for traffic headed into the mainland.

When you evaluate a China route, ask where the traffic enters the mainland and over whose backbone, not only whether a provider is present at an exchange. Ask for the AS path, the latency and loss baseline for your city pair, and what happens when a path fails; those answers describe the path you will actually use.

Which route fits? Connect to China

FAQ

Does peering at an exchange reach users in mainland China?

Only the networks present at that exchange. Traffic for users on networks inside the mainland is carried onto a Chinese carrier backbone, through IP transit, premium routing or a private line.

Is IP transit the same as peering?

No. Transit reaches the whole internet through one provider’s routes under one contract; peering reaches only the networks you agree to exchange traffic with.

Where do you peer?

We do not publish our peering or interconnection points. A route assessment covers what matters for your traffic: the option, the delivery point and the terms.

What is a route server?

A service at an exchange that distributes routes between members so each one does not have to configure a session with every peer. It shares routing information only. It does not carry traffic, and it does not make a peer accept your routes.

Is peering always cheaper than transit?

No. Peering needs a port, a cross-connect, a router and engineering time, and it reaches only the networks that agree to peer. For small volumes transit is usually cheaper; peering pays off when you exchange a lot of traffic with networks at the same exchange.

Plan the China part of your network

China circuits are quoted after a route assessment.