1990's addition to the hallowed tradition of April Fool RFCs was RFC 1149, A Standard for the Transmission of IP Datagrams on Avian Carriers. This sketched a method for transmitting IP packets via carrier pigeons.

Eleven years later, on 28 April 2001, the Bergen Linux User's Group successfully demonstrated CPIP (Carrier Pigeon IP) between two Linux machines running on opposite sides of a small mountain in Bergen, Norway. Their network stack used printers to hex-dump packets onto paper, pigeons to transport the paper, and OCR software to read the dumps at the other end and feed them to the receiving machine's network layer.

Here is the actual log of the ping command they successfully executed. Note the exceptional packet times.

Script started on Sat Apr 28 11:24:09 2001
vegard@gyversalen:~$ /sbin/ifconfig tun0
tun0 Link encap:Point-to-Point Protocol
inet addr:10.0.3.2 P-t-P:10.0.3.1 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:150 Metric:1
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0
RX bytes:88 (88.0 B ) TX bytes:168 (168.0 B )

vegard@gyversalen:~$ ping -i 450 10.0.3.1
PING 10.0.3.1 (10.0.3.1): 56 data bytes
64 bytes from 10.0.3.1: icmp_seq=0 ttl=255 time=6165731.1 ms
64 bytes from 10.0.3.1: icmp_seq=4 ttl=255 time=3211900.8 ms
64 bytes from 10.0.3.1: icmp_seq=2 ttl=255 time=5124922.8 ms
64 bytes from 10.0.3.1: icmp_seq=1 ttl=255 time=6388671.9 ms

— 10.0.3.1 ping statistics —
9 packets transmitted, 4 packets received, 55% packet loss
round-trip min/avg/max = 3211900.8/5222806.6/6388671.9 ms
vegard@gyversalen:~$ exit

Script done on Sat Apr 28 14:14:28 2001

A web page documenting the event, with pictures, is at http://www.blug.linux.no/rfc1149/. In the finest Internet tradition, all software involved was open-source; the custom parts are available for download from the site.

While all acknowledged the magnitude of this achievement, some debate ensued over whether BLUG's implementation was properly conformant to the RFC. It seems they had not used the duct tape specified in 1149 to attach messages to pigeon legs, but instead employed other methods less objectionable to the pigeons. The debate was properly resolved when it was pointed out that the duct-tape specification was not prefixed by a MUST, and was thus a recommendation rather than a requirement.

The perpetrators finished their preliminary writeup in this wise: “Now, we're waiting for someone to write other implementations, so that we can do interoperability tests, and maybe we finally can get the RFC into the standards track... ”.

The logical next step should be an implementation of RFC2549.

Source