There are two terms that I see often when looking at network traffic in Azure: Ingress and Egress.
But what are they? A quick define: search with google gives the following (not tech related) definitions:
In broad terms, ingress implies the action of entering, and egress implies exiting.
Definitions for Networking
In the context of network traffic, the terms have a very similar definition:
- Egress refers to any traffic that exits an entity, or a network boundary. This may also be referred to as outbound traffic.
- Ingress refers to traffic that enters the boundary of a network. This may also be referred to as inbound traffic.
Ingress is free, Egress is not.
Fortunately, in Azure, only egress is charged. Ingress is completely free.
There are a number of reasons why Azure might do this, including (but definitely not limited to):
- It's much easier to migrate customers to Azure when there is no initial ingress charge.
- Most customer data is egress. Typically, a user will make a small request to a cloud application (e.g., a user ID), and get a large amount of data in response (e.g., all that users information).
- All major cloud providers have decided not to charge for ingress. Azure would have to follow to remain competitive.