RFC 1226

Internet Protocol Encapsulation of AX.25 Frames 🎀

okay bestie, this is RFC 1226 and it's giving tiny, focused, experimental energy ✨ Here's the title-block tea 🫖

• It's from the Network Working Group, filed as Request for Comments: 1226 🦋
• The author is Brian Kantor at the Univ. of Calif San Diego (his address is at the bottom, obsessed 🙈)
• It's dated May 1991 🌸
• The category is Experimental Protocol 🧪
• The header doesn't list anything it obsoletes or updates, so it isn't replacing or changing any earlier RFC 💅

Status of this Memo 📝

okay so this memo describes a way to wrap AX.25 (the Amateur Packet-Radio Link-Layer Protocol) frames inside IP packets 📦 It's an Experimental Protocol for the Internet community, and they are literally asking for discussion and suggestions for improvement 🫶 For the standardization state and status, check the current edition of the "IAB Official Protocol Standards" 📚 Distribution of this memo is unlimited 🌈

The AX.25 Amateur Packet-Radio Link-Layer Protocol 📻

the whole AX.25 spec lives in its own publication, cited as [1], and it's incorporated here by reference, so this memo just borrows it 🤝

Each AX.25 packet ("frame") gets encapsulated in one IP datagram 💌 Normally no AX.25 frame will exceed 330 octets, so fragmentation at the IP layer SHOULD NOT be necessary 🧩 However, experiments with larger AX.25 frame sizes MAY require the use of standard IP fragmentation and reassembly procedures ⭐

here's the glow-up part 💖 When an AX.25 frame is encapsulated within an IP packet, the HDLC framing elements (flags and zero-stuffing) are omitted, since the IP datagram already marks the beginning and end of each AX.25 frame 🎯 The 16-bit CRC-CCITT frame check sequence (normally generated by the HDLC transmission hardware) is still included 🔐 In all other respects, AX.25 frames are encapsulated unaltered ✨

And the rule itself: each such IP datagram SHALL have a protocol number of 93 🔢👑

Reference 📚

[1] AX.25 Amateur Packet-Radio Link-Layer Protocol Version 2.0 October 1984. Available from the American Radio Relay League, Newington CT USA 06111, and other sources.

Security Considerations 🔐

okay, serious moment 💀 No security issues are discussed in this memo, so the RFC itself stays totally silent on that one 🙈

Author's Address 🖊️

Brian Kantor
University of California at San Diego
Network Operations C-024
La Jolla, CA 92093-0214

Phone: (619) 534-6865

EMail: brian@UCSD.EDU