LukeParke/unicorn-utterances
1
0
Fork 0
mirror of https://github.com/LukeHagar/unicorn-utterances.git synced 2025-12-09 12:57:45 +00:00
Code Issues Packages Projects Releases Wiki Activity

Initiate initial rewrite of article

Browse Source
This commit is contained in:
Corbin Crutchley
2020-03-29 20:52:54 -07:00
parent 2f29099fdf
commit be85bb7fd8
1 changed files with 186 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files

224
content/blog/networking-101-part-1-udp/index.md
View File

@@ -12,13 +12,102 @@
}
---
Networking is the foundation that all interactions of the internet are built upon. Every chat you send, every website you visit, every interaction that is shared with another digitially is built upon the same fundamentals. These fundamentals layout and explain how computers are able to communicate with one-another and how they interlink with one-another in order to provide you with the experience you've come to know and love with the internet.
In the last article in the series, we outlined what a packet architected network was, what the OSI layers represent, and demonstrated how we could use physical mail as an analogy for how packet-based networks function. Since we've gone to a hundred-mile view in the last series, I figured we'd take a look at what we deliver in an HTTP network. You see, the internet, as you know it, is merely a large scale HTTP network; it's built upon the packet architecture. There are two common types of packets that are delivered in the HTTP network: UDP and TCP.
# Commonalities {#udp-and-tcp-both}
Let's start by talking about what similarities UDP and TCP have. While they do have their distinct differences, they share a lot in common.
Since they're both packet-based, they both require an "address" of sorts to infer where they've come from and where they're going.
## IP Addresses {#ip-address}
### Different Types of IP Addresses {#ipv4-vs-ipv6}
While IP addresses may seem somewhat arbitrary at first glance, there are important rules to abide by to have what's considered a "valid" IP address. What's considered "valid" is defined by the TCP/IP specification, which is lead by the [Internet Engineering Task Force](https://en.wikipedia.org/wiki/Internet_Engineering_Task_Force), a group created specifically to manage and handle network protocol standardization. As time has gone on, there have been various revisions to the IP validation methods. What was once valid is now considered outdated and migrated to a newer standard of IP address. The two most commonly used standards for defining IP addresses today are:
- IPv4 (Internet Protocol version 4)
- IPv6 (Internet Protocol version 6)
Due to the explosion of internet enabled-devices, we have had to make changes to the way we assign network addresses. The previous version of the IP protocol (v4) allowed for 4,294,967,296 (2^32) unique IP addresses. While this number may seem excessive, it's important to realize that we ran out of unique IP addresses in 2017. The only reason why we even lasted that long is due to a myriad of techniques that networking companies (like your ISP) utilized to extend the life of the IPv4 protocol. With IPv6, we're able to have 340,282,366,920,938,463,463,374,607,431,768,211,456 (2^128) (yes, that's correct) unique addresses - no fear of immediate exhaustion of addresses.
![A showcase of an example IPv4 address and an IPv6 address. IPv4 example is "131.198.246.34" while IPv6 is "4131:e0fd:ef8e:ed27:f5b:ac98:640c:bfa5"](./ip-comparison.svg)
#### What Happened to version 5? {#ipv5}
As mentioned previously, the Internet Engineering Task Force manages various specifications regarding the standardization of internet communication. Back in 1995, they gathered to attempt to create a new version of the protocol to handle the growing use of live-streamed communication. To make a long story short, IPv5 was abandoned for various reasons, and they moved on to tackle the issue of unique identifiers rapidly diminishing. To avoid confusion with the attempted streaming protocol improvements, when a new version of the protocol was being worked on afterward, it was called IPv6.
> If you'd like to read more about this version for fun, you can read through [the Wikipedia page](https://en.wikipedia.org/wiki/Internet_Stream_Protocol). Unfortunately, there's limited information, and things get very quickly highly technical due to the "in progress" nature that things were left at.
## Ports {#udp-ports}
Continuing with the mail analogy, just like an apartment complex can have a single mailbox for multiple apartments living within the same building, so too can a single machine have multiple landing sites for network packets.
These separated landing sites are called "ports"; called as such because they operate very similarly to the seaside "ports" that are used to dock ships. You're able to "open" a port to start engaging in network activity through that port, or "close" it to stop communication from flowing through that port. A single machine may choose to open a myriad of ports ranging anywhere from `0` to `65,535`. Any one of these ports can receive a different stream of information in-bound and out-bound alike.
This method of port address selection even has it's own shorthand. For example, if you wanted to send data to IP address `192.168.1.50` on port `3000`, you'd send that data to: `192.168.1.50:3000`, being sure to use a colon to delineate between the IP address and the port number.
#### Pre-Assigned Ports {#standard-ports}
Like an apartment complex may pre-assign individuals to specific rooms, so too does the specification for Internet Protocol pre-assign specific applications to specific ports. For example, port 21 is officially designated to the [File Transfer Protocol (FTP)](https://en.wikipedia.org/wiki/File_Transfer_Protocol), which can be used to transfer files if a server is set up on a machine to handle this protocol. As a result, it's strongly discouraged to use these ports that are reserved for your application stack if you want to use a specific port for networking in your app or project.
In this series, we'll go through what these fundamentals are, how they're used and composed to makeup the communications you utilize on a day-to-day basis.
Let's start where most things tend to: The most simple to start with.
Let's start with **UDP**.
# UDP {#udp}
@@ -26,13 +115,103 @@ UDP is the **"User Datagram Protocol"**. Of the acronym, you may be familiar wit
If you're familiar with how a telegram (like the old-school messaging method, not the new-age messaging platform) used to work, you may already be familiar with how a datagram works.
_A datagram is a uni-directional, non-verifably-sent peice of communication that contains data._
_A datagram is a unidirectional, non-verifiably-sent piece of communication that contains data._
Whoa. What's that even mean?
Okay, let's take a step back and understand what's going on with a datagram. Let's imagine you want to send a letter with some information to a friend in another state. Using the postal service, you're unable to verify that your friend has recieved the letter, only wait for a reply. There's also interaction required in order to send a letter. So long as you know the address of your friend, you can send as many letters as you'd like.
In a typical correspondance, you'd send off a letter, include a return address, and wait for a response back. That said, there's nothing stopping someone from sending more than a single letter before recieving a response. This chart is a good example of that:
Okay, let's take a step back and understand what's going on with a datagram. Let's imagine you want to send a letter with some information to a friend in another state. Using the postal service, you're unable to verify that your friend has received the letter, only wait for a reply. There's also interaction required in order to send a letter. So long as you know the address of your friend, you can send as many letters as you'd like.
In a typical correspondence, you'd send off a letter, include a return address, and wait for a response back. That said, there's nothing stopping someone from sending more than a single letter before receiving a response. This chart is a good example of that:
![An image showcasing the rules of data sending both ways](./image-of-unidirectional-data-being-sent.svg)
@@ -56,37 +235,6 @@ These headers can contain information (also called "metadata") like what size th
`video: title: "A simulation of a packet that has a header stating the body to be in XML format being routed to a server that specifically handles XML files and a packet with a header that notes the data being in JSON being routed to a server that handles JSON": ./redirect-based-on-headers.mp4`
## Different Types of IP Addresses {#ipv4-vs-ipv6}
While IP addresses may seem somewhat arbitrary on first glance, there are important rules to abide to in order to have what's considered a "valid" IP address. What's considered "valid" is defined by the TCP/IP specification, which is lead by the [Internet Engineering Task Force](https://en.wikipedia.org/wiki/Internet_Engineering_Task_Force), a group created specifically to manage and handle network protocaul standardization. As time has gone on, there have been various revisions to the IP validation methods. What was once valid is now considered antiquated and migrated to a newer standard of IP address. The two most commonly used standards for defining IP addresses today are:
- IPv4 (Internet Protocol version 4)
- IPv6 (Internet Protocol version 6)
Due to the explosion of internet enabled-devices, we have had to make changes to the way we assign network addresses. The previous version of the IP protocol (v4) allowed for 4,294,967,296 (2^32) unique IP addresses. While this number may seem exorbant, it's important to realize that we ran out of unique IP addresses in 2017. The only reason why we even lasted that long is due to a myriad of techniques that networking companies (like your ISP) utilized to extend the life of the IPv4 protocol. With IPv6, we're able to have 340,282,366,920,938,463,463,374,607,431,768,211,456 (2^128) (yes, that's correct) unique addresses - no fear of immediate exhaustion of addresses.
![A showcase of an example IPv4 address and an IPv6 address. IPv4 example is "131.198.246.34" while IPv6 is "4131:e0fd:ef8e:ed27:f5b:ac98:640c:bfa5"](./ip-comparison.svg)
### What Happened to version 5? {#ipv5}
As mentioned previously, the Internet Engineering Task Force manages various specifications regarding the standardization of internet communication. Back in 1995, they gathered to attempt to create a new version of the protocol to handle the growing use of live-streamed communication. To make a long story short, this version was abandoned for various reasons and they moved on to tackle the issue of unique identifiers rapidly diminishing. In order to avoid confusion with the attempted streaming protocol improvements, this new version was called IPv6.
> If you'd like to read more about this version for fun, you can read through [the Wikipedia page](https://en.wikipedia.org/wiki/Internet_Stream_Protocol). Unfortunately, there's limited information and things get very quickly highly technical, due to the "in progress" nature that things were left at.
# Ports {#udp-ports}
Continuing on with the mail analogy; just like an apartment complex can have a single mailbox for multiple apartments living within the same building, so too can a single machine have multiple landing sites for network packets.
This method of seperating out locations for different network packets are called **"ports"**. A single machine may choose to open a myriad of ports ranging anywhere from `0` to `65,535`. Any one of these ports is able to recieve a different stream of information in-bound and out-bound alike.
This method of port address selection even has it's own shorthand. For example, if you wanted to send data to IP address `192.168.1.50` on port `3000`, you'd send that code to: `192.168.1.50:3000`, being sure to use a colon to deliniate between the IP address and the port number.
That said, UDP does not require you specify a port, you're able to pass port `0` to have the server dynamically decide the port used to communicate, if it does have a preference.
## Pre-Assigned Ports {#standard-ports}
Like an apartment complex may pre-assign individuals to specific rooms, so too does the specification for Internet Protocol pre-assign specific applications to specific ports. For example, port `21` is officially designated to the [File Transfer Protocol (FTP)](https://en.wikipedia.org/wiki/File_Transfer_Protocol), which can used to transfer files if a server is setup on a machine to handle this protocol. As a result, it's strongly discouraged to use these ports that are reserved for your application stack if you want to use a specific port for networking in your app or project.
# Conclusion
This has been a breif overview of UDP. In this series, we're hoping to introduce the fundamentals of networking, and while UDP is not often seen in higher-level coding directly, it's usage is integral to understand many other aspects of networking. In the next article in the series, we'll introduce TCP and how you're able to verify that your messages are being sent to the other client. Even further into the series, we'll explain how IP addresses are assigned by using UDP thanks to DHCP.