12 myths about how the Internet works

A list of assumptions we make when we hit the send button or download a video

Thirty years have passed since the Internet Protocol was first described in a series of technical documents written by early experimenters. Since then, countless engineers have created systems and applications that rely on IP as the communications link between people and their computers.

Here's the rub: IP has continued to evolve, but no one has been carefully documenting all of the changes.

"The IP model is not this static thing," explains Dave Thaler, a member of the Internet Architecture Board and a software architect for Microsoft. "It's something that has changed over the years, and it continues to change."

Thaler gave the plenary address Wednesday at a meeting of the Internet Engineering Task Force, the Internet's premier standards body. Thaler's talk was adapted from a document the IAB has drafted entitled "Evolution of the IP Model.''

"Since 1978, many applications and upper layer protocols have evolved around various assumptions that are not listed in one place, not necessarily well known, not thought about when making changes, and increasingly not even true," Thaler said. "The goal of the IAB's work is to collect the assumptions -- or increasingly myths -- in one place, to document to what extent they are true, and to provide some guidance to the community."

The following list of myths about how the Internet works is adapted from Thaler's talk:

1. If I can reach you, you can reach me

Thaler dubs this myth, "reachability is symmetric," and says many Internet applications assume that if Host A can contact Host B, then the opposite must be true. Applications use this assumption when they have request-response or callback functions. This assumption isn't always true because middle-boxes such as network address translators (NAT) and firewalls get in the way of IP communications, and it doesn't always work with 802.11 wireless LANs or satellite links.

2. If I can reach you, and you can reach her, then I can reach her

Thaler calls this theory "reachability is transitive," and says it is applied when applications do referrals. Like the first myth, this assumption isn't always true today because of middle-boxes such as NATs and firewalls as well as with 802.11 wireless and satellite transmissions.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.

Tags wireless lan

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Carolyn Duffy Marsan

Network World
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?