The Internet Routing Entropy Monitor

The Internet Routing Entropy Monitor is a tool for operators, practitioners, and theoreticians to obtain historic information about the information-theoretical entropy of Internet routing. The entropy closely characterizes the amount of information contained in an Internet routing table, and so it gives a glimpse into the short and long-term scalability and sustainability perspectives of the Internet data plane. The Internet Routing Entropy Monitor provides daily updated statistics from several real IP routers' forwarding tables and makes the raw data freely available for download.

The original intention to create the Internet Routing Entropy Monitor was to verify the seemingly unintuitive finding that the Internet routing ecosystem, shaped by the loosely orchestrated interactions of a huge number of autonomous decision makers, exhibits surprisingly low information-theoretical entropy, indicating that there is a very high level of regularity in Internet routes. This, on the one hand, suggests that routing table compression algorithms have high potential to reduce the memory footprint of routing tables, a key to dispel worrying Internet routing scalability concerns [1], [2]. On the other hand, compelling questions arise regarding the very nature and origin of this vast regularity. It is the hope of the fib_comp team that this service will prove itself useful for the Internet community to answer these fundamental questions.

The main difference from other routing monitoring services, like the University of Oregon Route Views Project, is that in contrast to those services that monitor the Routing Information Base (RIB), the Internet Routing Entropy Monitor analyses the Forwarding Information Base (FIB). Chiefly, the FIB contains correct and timely next-hop distribution (something the RIB, by nature, lacks), which is in turn indispensable to obtain accurate information-theoretical statistics from the Internet data plane.

Currently, the Internet Routing Entropy Monitor keeps track of 20 vantage points located in two remote Autonomous Systems (ASes), the Internet2 (AS 11537) and the HBONE (AS 1955). The IPv4 forwarding tables (FIBs) are downloaded from the vantage point routers on a daily basis, from which 4 FIBs are full-BGP while the rest are smaller FIB instances with internal routes predominantly. Statistics are created and published each day from the collected data.

To make the Internet Routing Entropy Monitor more useful, we need more data from as many routers as possible.

Please, give us your data! Share us your FIBs!

You can offer your FIBs for analysis via filling out the forms below.
Remember: our custom download scripts cause negligible CPU load on your router and the data we offer for download is next-hop-anonymized, making it impossible for others to reconstruct your routing policies.

[+] Background

Click the '+' sign to expand

Global statistics

The below diagrams give a glimpse into the data collected from each vantage point. For the statistics on individual vantage points, click here. All the diagrams are freely clickable. To magnify a region, draw a rectangle on the diagram. Click the right mouse button to reset to the time series. Click here for some background on these statistics and here for an explanation of the parameters given in the diagrams.

Entropy (\(H_0\))


Number of raw FIB entries


Vantage point statistics

The below table shows the statistics on the FIBs collected from the individual vantage point routers. Click on the '+' sign to expand the per-FIB statistics, which can then be collapsed again by clicking on the '-' sign.

FIB name Source Last update #Entries #Next-hops Entropy Size (KB)
[+] Atlanta Internet2 2018-06-23 0 0 0.0 0.0
[+] Chicago Internet2 2018-06-23 0 0 0.0 0.0
[+] Cleveland Internet2 2018-06-23 0 0 0.0 0.0
[+] Houston Internet2 2018-06-23 0 0 0.0 0.0
[+] KansasCity Internet2 2018-06-23 0 0 0.0 0.0
[+] LosAngeles Internet2 2018-06-23 0 0 0.0 0.0
[+] NewYork Internet2 2018-06-23 0 0 0.0 0.0
[+] SaltLakeCity Internet2 2018-06-23 0 0 0.0 0.0
[+] Seattle Internet2 2018-06-23 0 0 0.0 0.0
[+] Washington Internet2 2018-06-23 0 0 0.0 0.0
[+] hbone_bme HBONE 2018-06-23 699656 113 3.212522 3.1
[+] hbone_debrecen HBONE 2018-06-23 2306 113 3.278893 3.06
[+] hbone_miskolc HBONE 2018-06-23 2296 112 3.303742 2.99
[+] hbone_pecs HBONE 2018-06-23 2293 108 3.271226 2.97
[+] hbone_sopron HBONE 2018-06-23 2302 107 3.265645 2.95
[+] hbone_szeged HBONE 2018-06-23 699645 109 3.264407 3.01
[+] hbone_szolnok HBONE 2015-12-15 1971 88 3.297515 2.82
[+] hbone_veszprem HBONE 2018-06-23 2294 104 3.251142 2.94
[+] hbone_vh1 HBONE 2018-06-23 700228 240 2.229834 183.24
[+] hbone_vh2 HBONE 2018-06-23 699652 188 3.093849 3.32


If you need access to the next-hop anonymized data, please send an email to fib_comp [at]


The fib_comp team would like to thank for the Internet2, the NIIF HBONE for making their data available for analysis. Special thanks go to Levente Csikor for creating and maintaining the website.

The members of the fib_comp team:


[1] Gábor Rétvári, János Tapolcai, Attila Kőrösi, András Majdán, and Zalán Heszberger. Compressing IP forwarding tables: towards entropy bounds and beyond. In ACM SIGCOMM 2013, pages 111-122, 2013. [ bib | DOI | slides | paper ]
[2] Gábor Rétvári, Zoltán Csernátony, Attila Kőrösi, János Tapolcai, András Császár, Gábor Enyedi, and Gergely Pongrácz. Compressing IP forwarding tables for fun and profit. In Eleventh ACM Workshop on Hot Topics in Networks (HotNets-XI). ACM, October 2012. [ bib | slides | paper ]

We are greatly thankful for your help.
the fib_comp team

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