Give an example of a non transit AS

• A. A data center
• B. An organization that is multihoming with two ISPs
• C. A large ISP
• D. An Internet Exchange Point

Answer: (B)

Non-transit AS means an Autonomous System that does not carry traffic for other networks between two different ASes. It primarily connects to the Internet through one or more providers and may serve its own customers, but it does not act as a path for third parties to route traffic across.

The organization that is multihoming with two ISPs is the best example because it uses both providers for Internet access and redundancy, yet it does not function as a transit path for other networks. It doesn’t advertise routes to enable traffic to flow from one provider to another through its own AS, which is what a transit (or core) AS would do.

A large ISP, on the other hand, is a transit provider by design, forwarding traffic between many networks. An Internet Exchange Point is a peering facility used to exchange routes between networks, not a typical end-user AS that provides transit for others. A data center might host many tenants, but the canonical non-transit example is the multihomed organization.