The informed researcher

Tue, 05/18/2010 - 09:37 by Olivier Bonaventure • Categories:

A good researcher, young or old, must stay informed about the progress of his/her field. In the 20th century, the library was the researcher's best friend to stay informed. Most researchers spent some time regularly in the library to browse the table of contents of the new magazines and journals. Some companies even published special journals that contained abstracts of papers published in key journals. Current Contents was one of these journals.


Thu, 05/06/2010 - 12:57 by Benoit Donnet • Categories:

Internet Topology Discovery Using mrinfo

The Internet Group Management Protocol (IGMP - RFC1112) was initially designed to allow hosts to report their active multicast groups to the multicast router on their LAN. However, IGMP also provides some management tools such as the messages used by mrinfo. In practice, an mrinfo reply provides similar information as a show command on the router's command line interface. Therefore, mrinfo allows us to silently collect useful topological information.

LISP Tutorials

Wed, 03/31/2010 - 10:38 by Damien Saucez • Categories:

The Locator/Identifier Separation Protocol (LISP) is a proposal aiming at resolving some problem the Internet is facing today like the lack of inbound inter-domain traffic engineering or the continuous growth of the routing table.

The tutorials available on present LISP today

LISP Tutorial

Wed, 03/31/2010 - 10:34 by Damien Saucez • Categories:
Related software: 
Research topic related: 
Routing protocols
damien Saucez and Olivier Bonaventure
Presentation date: 
March 30, 2010

Tutorial to introduce the Locator/Identifier Separation Protocol proposal

Operational-oriented tutorials

20111202_lisp_tutorial_frnog18[pdf|zip] gives a short tutorial on LISP with deployment examples.

The slides have been presented at FRNOG 18 meeting in December 2011, podcast will be available on

Who wants an IP address in ?

Sat, 03/13/2010 - 00:50 by Olivier Bonaventure • Categories:

The IPv4 address space is becoming a scarce resource and the Internet Registries are working hard to reclaim unused IPv4 address blocks to be able to continue to allocate the requested address blocks. The is one of the candidate address blocks to be used within the coming months, but network operators are a bit frightened by the fact that there are probably many networks that already use private addresses such as or similar "simple IP addresses".

Network radix lookup

Sat, 02/27/2010 - 08:54 by Damien Saucez • Categories:

You frequently need to resolve IP addresses into their longest-match prefix? RADIX_UDP is for you ;-)

The tool loads a list of prefixes into a radix that can be queried in UDP. The syntax is simple, send a UDP segment in text with the first column being the IP, we don't care about the others ;-)

The server will reply with the same text but with the corresponding prefix prepended.


create a file "prefix.dat" with this content:

start the server:

./radix_udp prefix.dat 45005

query it

90% of all IPv4 addresses are allocated !

Wed, 01/20/2010 - 12:44 by Olivier Bonaventure • Categories:

Since the early nineties, the Internet community has been concerned by the consumption of IPv4 addresses and several techniques have been proposed and deployed to reduce the consumption of IPv4 addresses. Network Address Translation (NAT) and Classless Interdomain Routing (CIDR) have been very successful. Unfortunately, the pool of IPv4 addresses is finite and we will run out of IPv4 addresses soon.

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