Incomputer networking,IP over Avian Carriers (IPoAC) is an ostensibly functional proposal to carryInternet Protocol (IP)traffic bybirds such ashoming pigeons. IP over Avian Carriers was initially described inRFC 1149 issued by theInternet Engineering Task Force, written by David Waitzman, and released on April 1, 1990. It is one of severalApril Fools' Day Request for Comments.

Waitzman described an improvement of his protocol inRFC 2549,IP over Avian Carriers with Quality of Service (1 April 1999). Later, inRFC 6214—released on 1 April 2011, and 13 years after the introduction ofIPv6—Brian Carpenter andRobert Hinden publishedAdaptation of RFC 1149 for IPv6.^[1]

IPoAC has been successfully implemented, but for only ninepackets of data, with apacket loss ratio of 55% (due to operator error),^[2] and aresponse time ranging from 3,000 seconds (50 min) to over 6,000 seconds (100 min). Thus, this technology suffers from extremely highlatency.^[3]

On 28 April 2001, IPoAC was implemented by theBergen Linux user group, under the name CPIP (for Carrier Pigeon Internet Protocol).^[4] They sent ninepackets over a distance of approximately 5 km (3 mi), each carried by an individual pigeon and containing one ping (ICMP echo request), and received four responses.

Script started on Sat Apr 28 11:24:09 2001$ /sbin/ifconfig tun0tun0      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)$ ping -c 9 -i 900 10.0.3.1PING 10.0.3.1 (10.0.3.1): 56 data bytes64 bytes from 10.0.3.1: icmp_seq=0 ttl=255 time=6165731.1 ms64 bytes from 10.0.3.1: icmp_seq=4 ttl=255 time=3211900.8 ms64 bytes from 10.0.3.1: icmp_seq=2 ttl=255 time=5124922.8 ms64 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 lossround-trip min/avg/max = 3211900.8/5222806.6/6388671.9 msScript done on Sat Apr 28 14:14:28 2001

This real-life implementation was mentioned by the French member of parliamentMartine Billard in the FrenchNational Assembly,^[5] during debates aboutHADOPI.

In December 2005, a Gartner report onbird flu that concluded "A pandemic wouldn't affect IT systems directly" was humorously criticized for neglecting to consider RFC 1149 and RFC 2549 in its analysis.^[6]

Known risks to the protocol include:

• Carriers being attacked bybirds of prey. RFC2549: "Unintentionalencapsulation in hawks has been known to occur, with decapsulation being messy and the packets mangled."
• Carriers being blown off course. RFC1149: "Whilebroadcasting is not specified,storms can cause data loss."
• The absence of viable local carriers. RFC6214: "In some locations, such as New Zealand, a significant proportion of carriers are only able to execute shorthops, and only at times when the background level of photon emission is extremely low." This describes the flightless and nocturnal nature ofkiwi.
• Loss of availability of species, such as the extinction of thepassenger pigeon.
• Disease affecting the carriers. RFC6214: "There is a known risk of infection by the so-calledH5N1 virus."
• The network topologies supported formulticast communication are limited by the homing abilities of carriers. RFC6214: "... [carriers] prove to have no talent formultihoming, and in fact enter arouting loop whenever multihoming is attempted."

Rafting photographers already use pigeons as asneakernet to transport digital photos onflash media from the camera to the tour operator.^[7] Over a 30-mile (48 km) distance, a single pigeon may be able to carry tens of gigabytes of data in around an hour, which on an averagebandwidth basis compared very favorably to earlyADSL standards, even when accounting for lost drives.^[8]

On March 12, 2004,Yossi Vardi, Ami Ben-Bassat, and Guy Vardi sent three homing pigeons a distance of 100 kilometres (62 mi), "each carrying 20–22 tiny memory cards containing 1.3 GB, amounting in total of 4 GB of data." An effective throughput of2.27 Mbit/s was achieved. The purpose of the test was to measure and confirm an improvement over RFC 2549.^[8] Since the developers used flash memory instead of paper notes as specified by RFC 2549, the experiment was widely criticized as an example in which an optimized implementation breaks an official standard.^{[citation needed]}

Inspired by RFC 2549, on 9 September 2009, the marketing team of The Unlimited, a regional company in South Africa, decided to host a tongue-in-cheek pigeon race between their pet pigeon Winston and local telecom companyTelkom SA. The race was to send 4 gigabytes of data fromHowick toHillcrest, approximately 60 kilometres (37 mi) apart. The pigeon carried amicroSD card and competed against a Telkom ADSL line.^[9] Winston beat the data transfer over Telkom's ADSL line, with a total time of two hours, six minutes and 57 seconds from uploading data on the microSD card to completion of download from the card. At the time of Winston's victory, the ADSL transfer was just under 4% complete.^[10][11][12]

In November 2009, the Australian comedy/current-affairs television programHungry Beast repeated this experiment. TheHungry Beast team took up the challenge after a fiery parliament session wherein the government of the time blasted the opposition for not supporting telecommunications investments, saying that if the opposition had their way, Australians would be doing data transfer over carrier pigeons. TheHungry Beast team had read about the South African experiment and assumed that, as a developedWestern country, Australia would have higher speeds. The experiment had the team transfer a 700 MB file via three delivery methods to determine which was the fastest: a carrier pigeon with a microSD card, a car carrying aUSB stick, and aTelstra (Australia's largest telecom provider) ADSL line. The data was to be transferred fromTarana in ruralNew South Wales to the western-Sydney suburb ofProspect, New South Wales, a distance of 132 kilometres (82 mi) by road. Approximately halfway through the race, the internet connection unexpectedly dropped and the transfer had to be restarted. The pigeon won the race with a time of approximately 1 hour 5 minutes, the car came in second at 2 hours 10 minutes, while the internet transfer did not finish, having dropped out a second time and not come back. The estimated time to upload completion at one point was as high as 9 hours, and at no point did the estimated upload time fall below 4 hours.^[13]

A similar pigeon race was conducted in September 2010 by tech blogger (trefor.net) and ISP Timico CTO Trefor Davies with farmer Michelle Brumfield in ruralYorkshire, England: delivering a five-minute video to aBBC correspondent 75 miles away inSkegness. The pigeon (carrying a memory card with a 300 MB HD video of Davies having a haircut) was pitted against an upload toYouTube viaBritish Telecom broadband; the pigeon was released at 11:05 am and arrived in the loft one hour and fifteen minutes later while the upload was still incomplete, having failed once in the interim.^[14][15][16]

• Hyper Text Coffee Pot Control Protocol
• Pigeon post
• Semaphore Flag Signaling System
• Sneakernet

• "Carrier Pigeons Bringing Contraband into Prisons",Bruce Schneier, www.schneier.com (blog), June 27, 2008
• Pigeon-powered Internet takes flight, Stephen Shankland,CNET News, May 4, 2001
• "The Unlimited"
• Pigeon carries data bundles faster than Telkom, 10 Sep 2009, M&G
• RFC1149 Game

• April Fools' Day jokes
• Computer humour
• Internet architecture
• Link protocols
• Physical layer protocols
• Wireless networking
• Domestic pigeons

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