WEBVTT

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In this lesson,

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we will learn about network traffic management.

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Network traffic management involves the control, direction,

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and optimization of data flow across a network.

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Network traffic management tools

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include forward and reverse proxies

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as well as content delivery networks, or CDNs.

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Let's dive deeper into proxies

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and content delivery networks.

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We'll begin by discussing different types of proxy servers.

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Proxy servers are devices that create a connection

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between an end user's client machine

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and a remote resource, such as a web server.

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Proxies can be either physical, hardware-based appliances

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or software installed on a server

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within your infrastructure.

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Either way, proxy servers offer several key benefits,

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including improved speed, efficiency, security,

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and enhanced auditing capabilities.

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Speed and efficiency are enhanced

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through a process called Web caching.

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When a user requests a website through the proxy,

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the proxy retrieves the site from the web server

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and delivers it to the user.

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Simultaneously, the proxy stores a local copy of the website

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in its cache.

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The next time someone requests the same site,

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instead of retrieving it from the web server

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over a slow wide area network link,

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the proxy sends the cached version,

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saving both time and bandwidth.

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This works particularly well for static websites.

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However, this technique is less effective

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for modern Web 2.0 websites,

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like Facebook, Twitter, or Reddit,

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which rely heavily on user-generated content.

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Since each user receives a personalized experience,

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caching is far less efficient for these dynamic sites.

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Beyond caching.

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Another key benefit of a proxy server

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is increased security through content filtering.

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This is achieved by configuring the proxy

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with a list of acceptable and non-acceptable sites,

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allowing it to block access to sites

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deemed inappropriate or harmful.

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For instance, if an employee attempts to visit a website

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containing pornography or gambling while at work,

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the proxy can be configured to deny access.

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Similarly, it can block websites known to host malware

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or other harmful content,

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helping to protect the corporate network

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from security threats.

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A final benefit to proxy servers

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is that they provide valuable auditing capabilities

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as they can log every user request

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made to access the wide area network.

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These logs can be used to track attempts

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to access restricted sites,

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such as gambling or pornography, as mentioned earlier.

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Additionally, they allow for monitoring

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how much time employees spend on particular websites.

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For instance, if a manager suspects an employee

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is spending an excessive time on social media

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instead of working,

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they can request a report from the system administrators,

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who can query the proxy server logs

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to determine the exact time spent on each site,

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provided this is in line with the organization's policies.

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Now, everything I've discussed so far

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refers to a specific type of proxy

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known as a forward or transparent proxy.

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This type of proxy is typically positioned

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at the edge of a corporate network,

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and it is responsible for regulating outbound traffic

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according to your acceptable use policies.

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Often, it also hides the client's IP address

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and blocks any malicious incoming traffic

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that may be sent in response

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to the client's request to a remote server.

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But there is another type of proxy known as a reverse proxy.

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Unlike a forward proxy,

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a reverse proxy acts as an intermediary

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positioned at the edge of your corporate network,

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functioning as the endpoint for external users.

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Essentially, it serves as a gateway

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between your users and your application's origin server.

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For instance, if I'm hosting a web application

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on one of my servers,

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I can set up a reverse proxy to act as a middleman

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between remote users and my application.

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This allows the reverse proxy

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to receive connection requests,

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complete the TCP three-way handshake,

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and then connect the application's origin server

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to the end user.

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So, why would you want to use a reverse proxy?

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Well, it offers four main benefits,

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content caching, traffic scrubbing,

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IP masking, and load balancing.

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First, reverse proxies are useful for content caching.

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By deploying a reverse proxy

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in various locations around the world,

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they can act as part of a content delivery network, or CDN.

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For example, if my main web server hosting my website

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is in Miami, Florida,

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I could place reverse proxies in Japan,

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Germany, New York, and San Francisco.

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These proxies would each store a cached copy of my website,

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and any time I update the content in Miami,

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the changes would be compressed

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and cached across all these locations.

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This way, if a student in India requests my homepage,

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they would receive it from the closest and fastest proxy,

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such as the one in Japan,

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reducing load times and enhancing the user experience.

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As far as content delivery networks are concerned,

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a reverse proxy is part of the solution,

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but it doesn't fully address the challenge

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of delivering content quickly on a global scale.

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More on this in a few minutes.

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Second, reverse proxies can handle traffic scrubbing.

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Placing them in front of a backend web application server

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allows them to inspect and filter traffic

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before it reaches the servers.

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This helps mitigate distributed denial-of-service attacks

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since the proxies absorb the attack,

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keeping the backend servers safe.

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Reverse proxies also enhance security

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by filtering out malicious traffic

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when paired with a web application firewall.

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Third, reverse proxies provide IP masking.

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Just like a forward proxy hides the client's IP address,

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a reverse proxy hides the IP address

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of the application servers.

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This means clients only communicate with the proxy,

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keeping the server's IP addresses hidden.

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Fourth, reverse proxies can be used for load balancing.

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As gateways between users and web application servers,

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reverse proxies can distribute individual requests

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to any available server.

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This helps distribute the load

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across multiple backend servers,

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ensuring better performance and quality of service

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for end users.

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So, while both forward and reverse proxies

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offer valuable features like caching,

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traffic filtering, and security improvements,

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they don't fully address the challenge

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of delivering content quickly and efficiently

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to users across the globe.

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This is where content delivery networks, or CDNs,

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come into play.

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CDNs are designed to ensure that content

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such as website data, videos, or files

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is available to users as quickly as possible

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by distributing copies of the content

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to multiple servers located in different geographic regions.

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When a user requests content,

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the CDN delivers it from the server closest to them,

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reducing latency and improving the overall user experience.

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CDNs offer global scalability

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and are specifically optimized

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for handling large volumes of traffic.

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They can automatically route traffic

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to the most efficient server

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based on factors like location and network conditions,

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while also providing dynamic content acceleration

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and built-in distributed denial-of-service protection.

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This makes CDNs effective at delivering content seamlessly

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across large, geographically dispersed networks.

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So, remember, when you're thinking about proxies,

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there are two basic types,

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forward or transparent proxies, and reverse proxies.

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Forward proxies are focused

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on filtering and managing information

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that is leaving our networks,

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helping out with things like content filtering,

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security, and user activity monitoring.

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Reverse proxies filter information coming into our networks,

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serving as intermediaries between external users

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and our internal application servers.

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And they provide benefits like load balancing,

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content caching, and security.

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Finally, content delivery networks distribute content

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across multiple servers distributed globally,

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allowing users to access data from the nearest server.

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This ensures faster load times, reduced latency,

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and an overall better user experience.

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Content delivery networks also provide content acceleration,

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optimizing the delivery of dynamic and static content

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by routing traffic through the most efficient paths.

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By doing so, they reduce congestion

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and improve the speed at which content is delivered,

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even during periods of high traffic.