Egress Traffic

Egress Traffic

Every byte of data that traverses a network is categorized based on its direction—whether it's entering or exiting a system. This classification helps administrators, developers, and users ensure efficient and secure data management. 

Behind the scenes, a ballet of bytes dances silently, ensuring that your favorite show streams flawlessly, your urgent email reaches its recipient or your cloud-stored photos get shared with loved ones in a heartbeat. 

Central to this dance is "egress traffic." A term perhaps unheard of by many, but without it, our online experiences would be significantly different.

What is Egress Traffic?

Egress traffic refers to the flow of data packets exiting a network or system. In simpler terms, it's the data that your system or network sends out to the external world. Whether it's a website sending out data to a user's browser, an app updating its content, or even an email being sent to a recipient outside your organization—these are all examples of egress traffic.

Imagine your computer or server as a busy airport. The planes taking off, carrying passengers to various destinations, can be likened to egress traffic. They represent data packets leaving your system to reach other systems or devices. 

Just as airport authorities need to ensure that planes take off safely and reach their destinations without any hitches, network administrators have the responsibility to manage and monitor egress traffic effectively.


CDN's Role in Reducing Egress Cloud Traffic Costs

Content Delivery Networks (CDNs) play a pivotal role in the digital ecosystem, particularly when it comes to mitigating the costs associated with egress traffic. 

As organizations increasingly adopt cloud services, they face the challenge of managing and optimizing the costs of data transfer out of their cloud platforms. Here's where the role of CDNs becomes invaluable.

  1. Offloading Traffic: CDNs work by caching content closer to end-users. When a user requests content that's cached on a CDN edge server, the request is served by the CDN rather than fetching it directly from the origin server. This offloading mechanism reduces the amount of data that exits the cloud, thereby reducing egress traffic costs.
  2. Predictable Costs: By offloading a significant portion of traffic to CDNs, organizations can achieve more predictable data transfer costs. This is especially valuable for businesses that experience spikes in user demand, as the CDN can absorb a large volume of requests, preventing unexpected surges in egress costs.

Egress Traffic Use Cases

Egress traffic, being the outflow of data from a system, has multiple applications across varied sectors and scenarios. Here are some typical use cases where egress traffic is crucial:

Web Hosting and Content Delivery: 

When you visit a website, the server hosting that website sends data to your browser, ensuring that the webpage loads correctly on your device. 

Every bit of information—from images and texts to videos—represents egress traffic from the web server.

Cloud Services: 

Cloud providers, like AWS or Google Cloud, charge customers based on the egress traffic they generate. 

For instance, if you store data in the cloud and then download it to a local system, the data transfer out of the cloud platform constitutes egress traffic.

Email Servers: 

Whenever an organization sends out emails, be it newsletters, transactional emails, or any other form, the emails constitute egress traffic from the organization's email server.

Streaming Services: 

Platforms like Netflix or YouTube send out vast amounts of data to users' devices. 

Every movie, song, or video clip streamed by a user is egress traffic from the service provider's servers.

Online Gaming: 

Multiplayer online games require constant data exchange between the game server and players' devices. 

Every update, leaderboard score, or real-time game data sent from the server to players represents egress traffic.

VPN and Remote Access: 

When employees access corporate resources remotely via a VPN, any data sent from the company's servers to the employees' devices is egress traffic.

CDN Edge Servers: 

Content Delivery Networks (CDNs) use edge servers to cache and deliver content closer to end-users. 

Leveraging a multi CDN strategy can further optimize egress traffic, ensuring faster content delivery. When an edge server sends out cached content to a user, it generates egress traffic.

IoT Devices: 

The Internet of Things (IoT) ecosystem involves multiple devices communicating with central servers. 

Any data sent from these servers to IoT devices, like updates or commands, is considered egress traffic.


Ingress vs. Egress Traffic

'Ingress' and 'egress' traffic are two terms that describe the flow of data in and out of a network or system. Here, we'll delineate the key differences between these two types of traffic.

Ingress Traffic

Ingress traffic refers to the incoming data packets that enter a network or system. It's the data your system or network receives from external sources. Here are the primary characteristics and examples of ingress traffic:

Ingress traffic starts from an external source and targets a specific system or network. For instance, when a user sends a request to access a website, that request represents ingress traffic for the website's server.


  1. Website Access: The act of typing in a website URL and sending a request to access it results in ingress traffic for the server hosting the site.
  2. IoT Commands: When a central server sends commands to an IoT device, that command data entering the device is considered ingress traffic.
  3. VPN Connections: When employees initiate a connection to a corporate network via VPN, the initial connection request and data are ingress traffic for the corporate network.

Egress Traffic

Egress traffic, on the other hand, pertains to the data packets that leave a network or system, directed towards external entities. Here are its primary characteristics and examples:

Egress traffic originates within a specific system or network and is dispatched outwards. An example would be a cloud server sending data to a user's device.


  1. Web Hosting: A server sending webpage data, images, or videos to a user's browser is generating egress traffic.
  2. Streaming Services: When users stream content, platforms like Netflix send data (like movie files) to users' devices, which is egress traffic.
  3. CDN Edge Servers: Delivering cached content from edge servers to end-users results in egress traffic.

Key Differences

  1. The fundamental difference lies in their direction. Ingress is incoming traffic, while egress is outgoing traffic.
  2. Ingress traffic comes from external sources targeting a specific system or network, whereas egress traffic starts within a system or network and moves outwards.
  3. Ingress traffic is typically scanned for potential threats or malicious payloads, whereas egress traffic might be monitored for potential data breaches or leaks.
  4. In cloud environments, ingress and egress traffic might have different cost structures. For instance, some cloud providers might offer free ingress but charge for egress.
  5. Ingress traffic might be measured in terms of request rates or connection establishment rates. In contrast, egress could be assessed based on data volume or rate of data transfer.


In essence, egress traffic, though perhaps a term unfamiliar to many, ensures that our devices receive the content we seek, our messages reach their intended recipients, and our data gets to its destination safely and swiftly. It's the outbound journey of data, a reflection of our active digital footprints, be it a sent email, a shared photo, or a posted status update.

Published on:
December 28, 2023
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