NAME

     sc_prefixscan — scamper driver to test if a set of IPv4 links are point-to-point.

SYNOPSIS

     sc_prefixscan [-D] [-i infile] [-o outfile] [-p port] [-l logfile] [-U unix-socket]
                   [-w wait] [-x prefixlen]

     sc_prefixscan [-r data-file] [-x prefixlen]

DESCRIPTION

     The sc_prefixscan utility provides the ability to connect to a running scamper(1) instance
     and use it to collect data to infer if an IPv4 link is likely a point-to-point link using
     the prefixscan method.  An address B is the in-bound interface of a router in a traceroute
     path if we find an alias A' of the address A returned for the previous hop and A' is a /31
     or /30 mate of B, i.e. the link between A and B is a point-to-point link.  The prefixscan
     method infers A and A' are aliases if the IPIDs in responses to five alternating probes sent
     one second apart monotonically increase and differ by no more than 1,000, or probes to A and
     A' elicit responses with a common source address.  The first technique is a pairwise
     comparison similar to Ally, and the second is the Mercator technique.  The supported options
     to sc_prefixscan are as follows:

     -D      causes sc_prefixscan to detach and become a daemon.

     -i infile
             specifies a file containing a list of IPv4 address pairs adjacent in traceroute
             paths to test if they are point-to-point links.

     -o outfile
             specifies the name of the output file to be written during the data collection
             phase.  The output file will use the warts(5) format.

     -p port
             specifies the port on the local host where scamper(1) is accepting control socket
             connections.

     -l logfile
             specifies the name of a file to log progress output from sc_prefixscan generated at
             run time.

     -r data-file
             specifies the name of the data file to be parsed for point-to-point link inferences
             that were collected by sc_prefixscan in a previous data collection.

     -U unix-socket
             specifies the name of a unix domain socket where a local scamper(1) instance is
             accepting control socket connections.

     -w wait
             specifies the length of time in seconds to wait between probing the same IPv4
             address with different methods.  By default, sc_prefixscan waits five seconds
             between methods.

     -x prefixlen
             specifies the maximum size of prefix to consider.  By default, sc_prefixscan
             considers up to an IPv4 /30 prefix.

EXAMPLES

     Given a traceroute with the following path:

           traceroute to 192.0.30.64
           1 192.0.2.1
           2 192.0.32.10
           3 192.0.31.8
           4 192.0.30.64

     then to collect data to infer if the implied IPv4 links are point-to-point, put the links in
     a file named infile.txt formatted as follows:

           192.0.2.1 192.0.32.10
           192.0.32.10 192.0.31.8
           192.0.31.8 192.0.30.64

     and use a scamper(1) daemon listening on port 31337 using:

           sc_prefixscan -i infile.txt -o outfile.warts -p 31337

     To obtain the inferred point-to-point links from outfile.warts:

           sc_prefixscan -r outfile.warts

SEE ALSO

     scamper(1), sc_ally(1), sc_ipiddump(1), sc_wartsdump(1), sc_warts2text(1), sc_warts2json(1),

     M. Luckie and k. claffy, A Second Look at Detecting Third-party Addresses in Traceroute
     Traces with the IP Timestamp Option, Proc. Passive and Active Measurement Conference 2014.

     R. Govindan and H. Tangmunarunkit, Heuristics for Internet Map Discovery, Proc. IEEE INFOCOM
     2000.

     N. Spring, R. Mahajan, and D. Wetherall, Measuring ISP topologies with Rocketfuel, Proc. ACM
     SIGCOMM 2002.

AUTHORS

     sc_prefixscan was written by Matthew Luckie <mjl@luckie.org.nz>.