Internet RFCs (Requests for Comments) are one of the most significant influences on the conduct of the internet, and more generally, on the use of the IP protocol. In the IT community, the role of RFCs is recognized. Unfortunately, the same is not true in the AV community. Recognizing the importance of RFCs would hasten the integration of IT and AV. This lesson focuses on where RFCs came from, what they are, and how they influence IP technology.
In 1969 the predecessor to the internet, the ARPANET, was operated in a casual manner by researchers and computer scientists at major universities. One engineer at UCLA, Steve Crocker, wrote RFC 1, which was titled “Host Software.” He didn’t intend this to be a rule or standard. Rather, he sought input on its contents. Very quickly, the number of published RFCs grew. Gradually, they took on the tone of strong suggestions or guidelines. To a greater extent, they became definitions of protocols and guides as to how protocols could be used. For example, in 1981, the IP protocol was prescribed in RFC 791 and the TCP protocol was prescribed in RFC 793. If you contemplate the plethora of internet acronyms such as ICMP, TSL, RIP, and HTTP, you will find one or more RFCs that give the details of the protocol. The number of RFCs is approaching 9,000.
[Byte-Sized Lesson in AV/IP: Packet Structures]
Today, in the IT community, a new protocol or method is not likely to be accepted unless it is proposed as an RFC. These new specifications are first submitted to the Internet Engineering Task Force (IETF) as drafts. They may or may not be placed on a standards track, which is the path to formal approval. However, sometimes manufacturers feel they can obtain the credibility they need by publishing an RFC as “informational.”
While RFC documents are generally the guidelines that are used across the industry, there are some notable exceptions. This is especially true for audio and video transport. MPEG-DASH (Adaptive bitrate using HTTP) is specified in ISO/IEC 23009-1:2014. Yet, even here, RFCs 6983 and 7933 describe the use of DASH video in particular application scenarios. The IT community also treats the methods specified by certain major manufacturers such as Cisco and Microsoft as standards. These are referred to as de facto standards and are recognized as proprietary in nature. Within the AV industry, few de facto standards compete with the influence of the RFCs.
[Byte-Sized Lesson: How’s Your IT Lingo?]
Over the last several years, the Byte-Sized Lesson series has made an effort to inform you of the many methods and protocols used to deliver audio and video over IP networks. Nearly every IP related protocol we’ve covered has a corresponding RFC. A short list of audio/video RFCs includes 1890, 5334, 6416, and 4856. However, there are many more. With the growth of audio and video traffic on IP networks, the list will surely continue to grow.
