The Digital Millennium Copyright Act (DMCA) is a federal statute addressing copyright issues that arise due to new technologies, such as the Internet. The “Online Copyright Infringement Liability Limitation Act” added Section 512 to the Copyright Act, providing 4 safe harbors for online service providers. If they meet all the requirements of the provisions, service providers are not liable for damages for copyright infringement.

Section 512 is mainly written in terms of networking technologies, which makes sense as it applies to internet infrastructure and service providers. We have seen some confusion by the legal profession around some of the technical terminology, and we discuss one of these issues here.

Paragraph (a) of Section 512

Paragraph (a) of Section 512 is concerned with “Transitory Digital Network Communications” and is intended to exempt from copyright infringement service providers that provide network connectivity. The thinking here is that if the public would like to have access to the internet, that connectivity must be provided by someone, and that service provider may not have the ability or resources to police the digital content that flows through its networks.

For example, if person A posts a copyrighted image to their website and an internet user visits their website, that content is transmitted to the internet user via an internet service provider (ISP). But given the sheer number of websites and other forms of information on the internet, it is impractical for service providers to be aware of the copyright status of all this information and to try to filter what is delivered to internet users.

Paragraph (b) of Section 512

Paragraph (b) of Section 512 is concerned with “System Caching.” A cache (pronounced ‘cash’) is a storage facility that improves the performance of content delivery to end users. The simplest form of caching occurs on the end user’s own computer. The web browser saves most of the content viewed, so that when the internet user visits that same website again, the content does not need to be downloaded again. Of course, this only works for static content. Dynamic content, such as stock prices or the news, should always be downloaded from the web hosting service.

Service providers can store static content inside their data centers, or points of presence (PoPs) closer to end users so that popular websites can be served faster to multiple Internet users within close geographic proximity. Section 512 provides exemption to service providers for caching activities because caching is done purely for network performance purposes and is for the benefit of the Internet browsing public in general. In other words, cached content is not stored at the discretion of a service provider, but instead, it is simply a temporary copy of a website created by a third party, and cashing it is simply a part of delivering content to end users.

Temporary vs Transient Memory

Most websites change over time, and therefore it is important not to cache web content permanently. As an example, even news content can be cached for several minutes, but it should probably not be cached for several hours. Content caching is inherently a temporary storage activity, and this is why paragraph (b) describes cache as temporary storage.

This is in contrast with transient storage, which is what happens inside network switches that simply forward content from one network to the other. Perhaps the simplest example of such a network switch is a home Wi-Fi router, which connects the ISPs network to home devices. A Wi-Fi router simply forwards network packets from one network to the next. While doing so, the switch must store network packets in its memory until they are transmitted successfully to the next network destination. Such a storage is transient because it is purely for the purposes of transmission. Data packets are only stored in transient memory for a very short amount of time, typically milliseconds, but if retransmission is needed, it could be for several seconds.

On the other hand, caching can be done for several hours or several days and is done on caching servers specially built for that purpose.


Our hope is that the differences between transient and temporary storage are now intuitively clear for people in non-technical professions. We at Sidespin Group are in the business of explaining complex technical concepts to non-technical audiences. We do this in the context of litigation consulting, expert witness consulting, technology strategy consulting, and management consulting.