Push CDN vs Pull CDN

Push CDN vs Pull CDN

In this tutorial, we are going to discuss about Push CDN vs Pull CDN. Push CDN and Pull CDN are two different approaches to content delivery within a Content Delivery Network (CDN).

CDNs can be categorized into two types: Pull CDNs and Push CDNs. Both types aim to deliver content efficiently, but they differ in how they handle and distribute the content.

Pull CDN

• In a Pull CDN, the content is not stored on the CDN’s servers by default.
• In a Pull CDN, content is fetched or “pulled” from the origin server to the CDN’s edge servers when a user requests it.
• When a user requests content that is not yet cached on an edge server, the edge server fetches the content from the origin server.
• Once the content is cached on the CDN’s edge server, subsequent requests for the same content will be served directly from the CDN, reducing the load on the origin server.
• When the cached content expires or reaches its Time-to-Live (TTL), the CDN will fetch the content again from the origin server, ensuring that users receive up-to-date content.
• This approach is suitable for dynamic content or content that changes frequently, as it ensures that users always receive the latest version of the content.
• Pull CDNs are more flexible and can handle dynamic content effectively, but they may introduce slightly higher latency for the first request since the content needs to be fetched from the origin server.
• Examples of Pull CDNs include Cloudflare, Fastly, and Amazon CloudFront.

Advantages of Pull CDN

• Dynamic Content Handling: Pull CDNs excel at delivering dynamic content that changes frequently, such as personalized web pages, real-time data, or user-generated content. Since content is fetched from the origin server on-demand, users receive the latest version of the content.
• Ease of Implementation: Setting up a Pull CDN is often simpler than a Push CDN because content is fetched automatically from the origin server when needed. Content providers don’t need to proactively upload assets to the CDN’s servers, reducing management overhead.
• Scalability: Pull CDNs can handle sudden spikes in traffic more efficiently because content is fetched from the origin server dynamically. As traffic increases, additional edge servers can be deployed to handle the load without pre-populating them with content.
• Cost-Effectiveness: Pull CDNs can be more cost-effective for content providers with unpredictable traffic patterns or those who don’t want to incur additional storage costs for caching large volumes of content across multiple edge servers.

Disadvantages of Pull CDN

• Potential Latency: The initial request for content that is not yet cached on an edge server may experience slightly higher latency because the content needs to be fetched from the origin server. However, subsequent requests benefit from cached content, reducing latency.
• Increased Load on Origin Server: Since content is fetched from the origin server on-demand, there may be increased load on the origin server, especially during traffic spikes or when serving large files to multiple users simultaneously. Content providers need to ensure that their origin servers can handle the load efficiently.
• Cache Misses: Pull CDNs are susceptible to cache misses, where content is not available on any edge server and needs to be fetched from the origin server. Frequent cache misses can result in higher latency and increased load on the origin server.
• Limited Control: Content providers have less control over the caching process with Pull CDNs compared to Push CDNs. They rely on the CDN’s caching algorithms to determine which content to cache and for how long, which may not always align with their preferences.

Push CDN

• In a Push CDN, the content is “pushed” to the CDN’s servers by the content provider, usually through manual uploads or automated processes. The content is proactively distributed across the CDN’s edge servers, making it readily available for user requests.
• In a Push CDN, content is uploaded or “pushed” to the CDN’s servers in advance of user requests.
• Content providers proactively upload their assets to the CDN’s servers, typically using FTP, SCP, or similar protocols.
• This approach is beneficial for content that doesn’t change frequently, such as images, videos, and other static assets.
• Push CDNs are suitable for scenarios where content updates are predictable and can be scheduled in advance.
• Examples of Push CDNs include Rackspace Cloud Files and Akamai NetStorage.

Advantages of Push CDN

• Low Latency: Since content is pre-loaded onto CDN edge servers, users can access it with lower latency compared to Pull CDNs. Content is readily available on edge servers closest to the user, reducing the time needed to fetch it from the origin server.
• High Availability: Pre-loading content onto edge servers ensures that it is readily available to users, even in the event of origin server downtime or network issues. This improves overall availability and reliability of content delivery.
• Reduced Load on Origin Server: By distributing content to edge servers in advance, Push CDNs reduce the load on the origin server. This can help optimize the performance of the origin server and ensure it can handle other tasks effectively.
• Cache Control: Content providers have more control over caching with Push CDNs. They can specify which content to cache, how long to cache it for, and where to distribute it, allowing for fine-tuning of caching policies to optimize performance.

Disadvantages of Push CDN

• Storage Costs: Pre-loading content onto edge servers requires additional storage space, which may incur extra costs for content providers, especially for large volumes of content or frequent updates. However, these costs can vary depending on the CDN provider’s pricing model.
• Complexity of Management: Managing content distribution across multiple edge servers can be more complex with Push CDNs, especially for content providers with large libraries of content or frequent updates. Content must be uploaded and managed across multiple edge servers, which requires coordination and monitoring.
• Scalability Challenges: Scaling a Push CDN to accommodate sudden spikes in traffic may be more challenging compared to Pull CDNs. Additional edge servers need to be provisioned and populated with content in advance, which may require more time and resources.
• Potential Staleness: Pre-loaded content may become stale if it is not updated frequently enough. Content providers need to ensure that updates are pushed to edge servers in a timely manner to avoid serving outdated content to users.

In summary, Push CDNs are more suitable for static content with predictable update schedules, while Pull CDNs are better suited for dynamic content or content that changes frequently. Each approach has its advantages and disadvantages, and the choice between them depends on factors such as the nature of the content, update frequency, and performance requirements.

That’s all about the Push CDN vs Pull CDN. If you have any queries or feedback, please write us email at contact@waytoeasylearn.com. Enjoy learning, Enjoy system design..!!