RFC 1375
Suggestion for New Classes of IP Addresses
RFC 1375 💖 Suggestion for New Classes of IP Addresses
Okay bestie, this is RFC 1375, "Suggestion for New Classes of IP Addresses" 🦋 It was written by P. Robinson and Tansin A. Darcos & Co., and it's dated October 1992. Its status is informational, so it's here to inform the Internet community and isn't a standard ✨ The document doesn't say it obsoletes or updates any other RFCs, so it's giving main character energy all on its own 🌸
Status of this Memo 📜
So this memo is just here to give info to the Internet community 🫶 It doesn't specify an Internet standard, and distribution is unlimited, so anyone can share it 💜
Abstract 🌈
The big idea: this RFC suggests changing how IP addresses are specified so we can add brand new network classes called F, G, H, and K 🎀 The goal is to waste way less address space and make more addresses available, especially for smaller organizations or types of connectors who don't need (or want) a full Class C IP address 💅
Table of Contents 📚
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Suggestion for new IP address classes . . . . . . . . . . . . . 2
Current Class C Address . . . . . . . . . . . . . . . . . . 3
Proposed new Class C Address . . . . . . . . . . . . . . . 4
Proposed "Class F" address . . . . . . . . . . . . . . . . 4
Proposed "Class G" address . . . . . . . . . . . . . . . . 4
Proposed "Class H" address . . . . . . . . . . . . . . . . 5
Proposed "Class K" address . . . . . . . . . . . . . . . . 5
Optional selection of routing codes by region . . . . . . . . . 5
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Security Considerations . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7Introduction 🌸
Right now, IP addresses on the Internet are 32-bit quantities 🔢 They're usually written as four decimal numbers from 0 to 255, separated by periods. That's the "dotted" decimal number, and it's iconic. The current scheme gives us three classes of networks in general use (A, B, and C), plus two other classes, D and E 💖
Class A networks give a large address space to a particular network, so it can have up to 254^3 local machines [1] 😭 Class B gets a somewhat smaller address space and allows up to 254^2 local machines 🍓 Class C gets an even smaller one and allows up to 254 local machines 🧚
This memo proposes taking part of the unused Class C address space and giving smaller networks something that actually fits them 💅 The term "Class D" is used for the "multicast" capability, and addresses in "Class E" are reserved for future use. So these new features that are going to be added are being called classes F, G, H, and K 🦋
Suggestion for new IP address classes 💌
Okay, the most worrisome problem in the literature is the possibility of running out of IP address space 😰 Various schemes are being suggested to deal with it, like subrouting, adding more bits, and other possibilities.
But there's an even more serious matter, ngl 😬 I suspect that eventually the Internet backbone will either become available to anyone who wants to use it, like public highways, with the costs paid out of taxes or some other method that gets someone else to foot the bill 🚗 Or the Internet will be fully commercialized and made available to anyone who wants to buy a permanent connection. As hardware and connection costs drop, some Computer Bulletin Board Systems (BBSs) that you can currently reach by phone call may become accessible via TELNET or FTP 📞➡️🌐 When a 9600 baud connection can be had for around the price of a phone line, the demand for internet access will skyrocket 🚀 That almost-certain availability to virtually anyone who wants a connection will cause an even greater demand for internet addresses, and it'll make this situation even worse 😩
One problem is the granularity of IP addressing. The smallest possible IP address you can get allows for as high as 254 IP addresses. If someone only wants to put four or five computers on the Internet, more than 240 addresses are wasted 🙈
Lots of smaller installations would probably be interested in putting their computers and/or servers on the Internet (and maybe helping pay the cost of running it 💸), or in accessing the Internet directly and making some of their machines' facilities available to others 🫶 The problem is that IP addresses on the Internet aren't readily available to small classes of users 😤 There's also the possibility of eventually putting non-computer, output-only devices like printers, facsimile machines, and visual pagers directly on the Internet 🖨️ That way, you could send a message to a local device simply by directing it to a specific internet site as an E-Mail message 📧
The scheme this paper proposes is a slight change to one of the classes of network address 🎀 It shouldn't be a significant problem to implement, and it shouldn't be a big hardship, since the addresses it would use aren't allocated right now anyway 🙌 It may also pull some of the demand that would have eaten through Class C addresses in large quantities into Class F, H, or K addresses, which waste less IP address space 🌈
Here's how it works: this scheme allows for very small networks (1 or 2, 1-7, or 1-15, depending on how many addresses the administrator of that site thinks they'll need 📋). It does this by reconstructing the network address so that it includes what is nominally part of the local address 🧩 If bridges and routers (and other hardware and software) don't assume that only the last 8 bits make up a local address, and they permit smaller spaces for local addresses, then this method shouldn't cause problems 🤞 Sites needing less than a close order of 256 IP addresses could simply apply for 2 or more contiguous blocks of Class F numbers 💖
Current Class C Address 🧱
Right now, a Class C address is a 32-bit number where the leftmost 3 bits are 110 [2]. The third type of address, class C, has a 21-bit network number and an 8-bit local address. Its three highest-order bits are set to 1-1-0, which allows 2,097,152 class C networks 🔢
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 1 0| NETWORK | Local Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Current Class C AddressProposed new Class C Address 🆕
This memo proposes changing Class C addresses to be 4-bit numbers beginning with 1100 🥹 Under the new version, the third type of address, class C, has a 20-bit network number and an 8-bit local address. The four highest-order bits are set to 1-1-0-0, which allows 1,048,576 class C networks.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 1 0 0| NETWORK | Local Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Proposed new Class C AddressThis memo then proposes adding four new types of addresses, called "Class F", "Class G", "Class H", and "Class K" [3] ✨ All of them would use part of the "old" class C address space by starting with the 4-bit sequence 1101. Class F addresses begin with the binary sequence 11010, Class G addresses begin with 110110, Class H addresses begin with 1101110, and Class K addresses begin with 1101111.
Proposed "Class F" address 🦋
Class F addresses will be used for networks having from 1-15 sites [4], where the number could be expected to exceed 7 😌 The sixth type of address, class F, has a 23-bit network number and a 4-bit local address. Its five highest-order bits are set to 1-1-0-1-0, which allows 16,777,256 class F networks.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | Local |
|1 1 0 1 0| NETWORK |Address|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Proposed "Class F" addressProposed "Class G" address 🌸
Class G is reserved for future use 🔮 The seventh type of address, class G, has its six highest-order bits set to 1-1-0-1-1-0.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
|1 1 0 1 1 0| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Proposed "Class G" addressProposed "Class H" address 💜
Class H is for small networks which are not expected to exceed 7 connected IP addresses 🐣 The eighth type of address, class H, has a 22-bit network number and a 3-bit local address. The seven highest-order bits are set to 1-1-0-1-1-1-0, which allows 4,194,304 Class H addresses [5].
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |Local|
|1 1 0 1 1 1 0| NETWORK | Addr|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Proposed "Class H" addressProposed "Class K" address 🍓
Class K is for sites which will either only have one or two connected addresses [6] 🥰 The eighth type of address, class K, has a 25-bit network number and a 1-bit local address. The seven highest-order bits are set to 1-1-0-1-1-1-1, which allows 33,554,432 Class K addresses [7].
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |*|
|1 1 0 1 0 0| NETWORK | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* = Local Address, 1 or 0
Proposed "Class K" addressOptional selection of routing codes by region 🌍
Okay bestie, so because things could get confusing 😵💫, the author suggests a method kinda like the international dialing plan 📞. The idea is that bits 5-8 in Class F, bits 7-10 in Class H, and bits 6-9 in Class K could be used to show what part of the world an address is in. It works like the phone system, where the first digit of an international number tells the network which region it's calling ✨. Here's how the international dialing codes are currently assigned:
1 North America 6 Oceania, Australia
2 Africa 7 Ex-Soviet Union Countries
3 Europe 8 Asia
4 Europe 9 Mideast
5 South America and MexicoIf we copy this kind of system 💅, the author would recommend giving 0, 1, 10 and 11 to North America, 8 and 12 to Asia, and keeping 13 through 15 open for other areas as needed 🌸. ngl this would only make some routing choices easier 🦋. It's not actually required, because routing today is usually done by picking the shortest path to a site, and IP numbers don't really match up with any specific spot on the map 🗺️.
The number form of a class F, G, H or K address can still be written as n.n.n.n 🎀. Just don't assume the 4th number alone tells you the local address, and don't assume that numbers sharing the same first 3 parts always belong to the same network 🙈.
Summary
Okay so here's the main ask 🫶. Even if the method for doing all this isn't ready yet, the author suggests taking Class F, G, H, and K address space out of Class C space 🧁. That space would be reserved for smaller networks, so this feature can be made available later 💜. And honestly, it shouldn't be a problem, since Class C addresses are currently only using the equivalent of one Class A number anyway 👑.
Notes
[1] Common practice dictates that neither an address 0 nor 255 should be used in any "dotted" address. 🙅♀️
[2] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1340, USC/Information Sciences Institute, July 1992. 📚
[3] To prevent confusion, no class "I" or "J" address was created by this memo. 🙃
[4] It is expected that if the higher part of the network address occupying the 4-bits to the left of the Class F address are neither 0 nor 15, that a class F site could have 16 machines. If the 4-bits to the left are all 0, the Class F site must not use number 0. If the four bits are all 1, the site must not use number 15. 🔢
[5] It may be that Class H numbers are more appropriate for classes of addresses that will not have as high a demand for access via Internet addresses such as facsimile machines and pagers. (The end digit could be used to determine class of service, i.e., 0 for tone only, 1 and 2 for numeric only, 3 4 and 5 for alphanumeric, and 6 and 7 for facsimile machines. Or some combination of these according to the demand. Remember, Internet won't always be just text messages and file transfers; we may eventually see things like voice telephone calls or voice data being placed to an Internet address just like calls made via the telephone system. This would require a whole change in the way things are done, but it's always best to look at the future. 📠📟 The future is literally so bright rn ✨
[6] It is suggested that addresses in this range not be assigned where the 7 bits to the left of the local number are all the same (all 0 or all 1), to allow all Class K addresses to have two local addresses. 🧩
[7] Different things can be done with different capabilities. One thought was to set up some group of numbers and use them to indicate systems which are "gateway" systems, i.e., the top set of numbers in Class K could indicate that subnets are required after those numbers, similar to the use of an extension number on the switchboard of a large organization. Another possibility is to assign some of the numbers to specific classes of devices, such as number-only pagers and electronic display devices. 🪄
Security Considerations
Security issues are not discussed in this memo. 🔐 I know, I know, this is a lot. Please go check on your security stuff anyway, bestie 😭💀
Author's Address
Paul Robinson
Tansin A. Darcos & Company
8604 Second Avenue #104
Silver Spring, MD 20910 USA
Phone: 202-310-1011
Telex: 6505066432MCI UW
E-mail: TDARCOS@MCIMAIL.COMAnd that's the whole RFC, bestie! 🌈💖
📦 where this page comes from
- ietf: rfc1375 1992-10
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms