Daryl's Subnet Calculator

This document is designed to give the reader a reasonable working knowledge of TCP/IP subnetting, addressing, and routing. It is not intended to be complete, or to cover all issues. This is targeted toward LAN administrators just moving to TCP/IP, however it should help anyone who wants to know a little (more) about how TCP/IP works. This document does not, generally, apply to dial-up SLIP/PPP connections.

The difference between this (a primer) and an FAQ, is that most FAQ's, in practice, tend to be question-and-answer oriented, and generally seem to try to cover ALL issues, not just the ones frequently asked about. This primer is intended as a starting point for someone who has an interest in the subject, but doesn't know where to start or what questions to ask. This should also help to broaden the understanding of people who have worked with TCP/IP for a while, but either haven't had the time to study all the less-than-useful theory behind the subject, or have been somewhat overwhelmed by the many theoretical details and have missed the big picture.

“The FCC is dishonestly claiming that it is promoting equity and fairness. However, the FCC is just seizing control over business decisions, funneling resources to politically preferred constituencies.” //

Congress, in the 2021 bipartisan infrastructure bill, delegated to the FCC the task to “ensure that all people of the United States benefit from equal access to broadband internet access.”

In fact, the agency found no evidence of intentional discrimination, but the leftists on the FCC used Congress’ delegation as an excuse to force equity and diversity mandates ranging from controls over discounts, language options, and credit checks to marketing and advertising.

The Internet started in the 1960s as a way for government researchers to share information. Computers in the '60s were large and immobile and in order to make use of information stored in any one computer, one had to either travel to the site of the computer or have magnetic computer tapes sent through the conventional postal system.

Another catalyst in the formation of the Internet was the heating up of the Cold War. The Soviet Union's launch of the Sputnik satellite spurred the U.S. Defense Department to consider ways information could still be disseminated even after a nuclear attack. This eventually led to the formation of the ARPANET (Advanced Research Projects Agency Network), the network that ultimately evolved into what we now know as the Internet. ARPANET was a great success but membership was limited to certain academic and research organizations who had contracts with the Defense Department. In response to this, other networks were created to provide information sharing.

January 1, 1983 is considered the official birthday of the Internet. Prior to this, the various computer networks did not have a standard way to communicate with each other. A new communications protocol was established called Transfer Control Protocol/Internetwork Protocol (TCP/IP). This allowed different kinds of computers on different networks to "talk" to each other. ARPANET and the Defense Data Network officially changed to the TCP/IP standard on January 1, 1983, hence the birth of the Internet. All networks could now be connected by a universal language.

SpaceX also faulted the FCC for relying on Ookla speed tests:

For instance, the Bureau's decision arbitrarily penalized SpaceX—and only SpaceX—for not meeting RDOF speed requirements years before SpaceX had any obligation to do so. The arbitrariness of applying this unstated standard exclusively to SpaceX was only compounded by the Bureau's reliance on Ookla nationwide speed tests without any notice that it planned to use such tests and even though those nationwide averages included areas that would not be served by RDOF. Even so, Starlink likely recorded the fastest speeds of any operator in the locations eligible for RDOF funds... Starlink has also deployed its service in advance of all RDOF deployment milestones and well ahead of most, if not all, RDOF awardees.

Notice the format of the hostname: ::ffff:a.b.c.d

I had to look this up: this is a IPv4-mapped IPv6 address. It is a format to describe an IPv4 address using a IPv6 address format.

From Wikipedia article on IPv6 addresses:

::ffff:0:0/96 ? This prefix is used for IPv6 transition mechanisms and designated as an IPv4-mapped IPv6 address.

With a few exceptions, this address type allows the transparent use of the transport layer protocols over IPv4 through the IPv6 networking application programming interface. In this dual-stack configuration, server applications only need to open a single listening socket to handle connections from clients using IPv6 or IPv4 protocols. IPv6 clients are handled natively by default, and IPv4 clients appear as IPv6 clients at their IPv4-mapped IPv6 address. Transmission is handled similarly; established sockets may be used to transmit IPv4 or IPv6 datagram, based on the binding to an IPv6 address, or an IPv4-mapped address.

The IPv4 part of the address can also be represented in hexadecimal: ::ffff:aabb:ccdd

Instead of carefully crafting a framework that identifies bad actors, describes their discriminatory actions, and outlines solutions to them, the FCC just assumes everyone is guilty. The regulators will treat any entity that tries to build up the next generation of internet access as purveyors of systemic injustice. The agency’s order does not give tangible examples of violations but operates under the premise that it should punish all broadband internet companies.

The regime applies to every company in the broadband internet space. It even applies to the small business contractors who build and maintain the infrastructure. These operators and technicians simply build where governments have permitted them to construct cell towers or lay fiber. But if the FCC deems that their work promotes discrimination, then bureaucrats will investigate and punish the workers on the frontlines.

This bureaucracy will hamstring the entire internet ecosystem. The rules will hinder industry leaders from developing and deploying new technologies that could transform internet access. Companies might fear that the FCC will interpret their best efforts as discrimination if all communities do not have an “equitable” opportunity to adopt the innovations. //

For example, in Pennsylvania, the population of Amish residents in Lancaster County is more than 39,000. As we learned from last month’s emergency alert test, there are quite a few Amish individuals who enjoy digital connectivity. If the FCC does not think enough Amish people subscribe to cell phone plans or use Wi-Fi in their barns, then the agency has granted itself the authority to investigate the supposed shortcoming as a violation of the digital discrimination order. Think of the absurdity: The FCC could actually punish a provider for not selling cellphones to enough Amish people. With this new regime, it is clear there are no limits to what the FCC will consider a breach. //

Instead of an arbitrary and undefined regime, the FCC would better serve the nation by establishing a framework that encourages cities and municipalities to promote the deployment of next-generation internet access. Too many communities, such as New York City, are dragging their feet. Others, like San Jose, are delaying deployment by charging internet providers exorbitant fees to build out these transformative networks.

It is clear the FCC’s rules are not concerned with improving internet access and upward mobility. Instead, they’re intended to dramatically expand the federal government’s power. There are real challenges to closing the digital divide, but the new order will not help that effort.

Now is the time to empower creators and innovators who are bringing new ideas to life. The FCC should work to promote new opportunities and technologies that will enable upward mobility rather than create a regime that punishes entrepreneurs who dare to take chances.

See this page fetch itself, byte by byte, over TLS

• This page performs a live, annotated https: request for its own source. It’s inspired by The Illustrated TLS 1.3 Connection and Julia Evans’ toy TLS 1.3.
• It’s built on subtls, a pure-JS TLS 1.3 implementation that depends only on SubtleCrypto. Raw TCP traffic is carried via a serverless WebSocket proxy.

The history of TCP congestion control is long enough to fill a book (and we did) but the work done in Berkeley, California, from 1986 to 1998 casts a long shadow, with Jacobson’s 1988 SIGCOMM paper ranking among the most cited networking papers of all time.

Slow-start, AIMD (additive increase, multiplicative decrease), RTT estimation, and the use of packet loss as a congestion signal were all in that paper, laying the groundwork for the following decades of congestion control research. One reason for that paper's influence, I believe, is that the foundation it laid was solid, while it left plenty of room for future improvements–as we see in the continued efforts to improve congestion control today.

And the problem is fundamentally hard: we’re trying to get millions of end-systems that have no direct contact with each other to cooperatively share the bandwidth of bottleneck links in some moderately fair way using only the information that can be gleaned by sending packets into the network and observing when and whether they reach their destination. //

It seems clear that there is no such thing as the perfect congestion control approach, which is why we continue to see new papers on the topic 35 years after Jacobson’s. But the internet's architecture has fostered the environment in which effective solutions can be tested and deployed to achieve distributed management of shared resources.

In my view that’s a great testament to the quality of that architecture. ®

As exhausting as it is to read that list, the FCC itself says it is not an exhaustive list. The Biden administration’s plan empowers the FCC to regulate every aspect of the internet sector for the first time ever. The plan is motivated by an ideology of government control that is not compatible with the fundamental precepts of free market capitalism.

But it gets worse.

The FCC reserves the right under this plan to regulate both “actions and omissions, whether recurring or a single instance.” In other words, if you take any action, you may be liable; and if you do nothing, you may be liable.

There is no path to complying with this standardless regime. It reads like a planning document drawn up in the faculty lounge of a university’s Soviet Studies Department.