We look at a particular usage of Object Storage as Content Distribution Network (CDN). The latter is merely a collection of proxy servers. Typically, proxy servers have local storage while object storage unifies the storage and exposes a single endpoint for the object. This would mean replicating the object over multiple geographical zones from the same object storage. Regardless of the topology of the storage where the assets are made available, any service requiring to use the content can rotate through one or more CDNs for downloading it to the device.
Typically a CDN is enabled over object storage using a gateway. A Rados gateway for example enables content to be served from a distributed object storage. In order to read an object, a rados gateway will create a cluster handle and then connect to a cluster. Then it opens an IO context and reads the data from the object following which it closes the context and the handle. This gateway is implemented in the form of a proxy FastCGI module and can be used with any web server that supports such module.
The use of a gateway facilitates server-load-balancing, request routing and content services. It can be offloaded to hardware. Gateways may perform web switching or content switching  They need not be real web servers and can route traffic to other web servers. They may be augmented to monitor servers in order to change forwarding rules. Rules may be made simpler with good addressing instead of using lookup. Also, a gateway is generally assigned a single virtual IP address.
Moreover, not all the request need to reach the object storage. In some cases web caches may be used. A gateway can forward a request to a web cache just the same way as it forwards a request to a web server. The benefits of using a web cache including saving bandwidth, reducing server load, and improving request-response time. If a dedicated content store is required, typically the caching and server are encapsulated into a content server. This is quite the opposite paradigm of using object storage and replicated objects. to directly serve the content from the store. The distinction here is that there are two layers of functions - The first layer is the gateway layer that solves distribution using techniques such as caching, asset copying and load balancers. The second layer is the compute and storage bundling in the form of a server or a store with shifting emphasis on code and storage.
The two layers need to adhere to the end to end principle which is best to do with a DiffServ paradigm