DisCarte

Papers

Sigcomm 2008 paper DisCarte: A Disjunctive Internet Cartographer

Code

Discarte is part of the sidecar package as of version 0.02: sidecar-0.2.tar.gz

Topologies in "adj" format

Whole Internet map (attempted) Measurements started on January 23, 2007 and proceeded for 5 days
Intra-planetlab topology (between all pairs of planetlab nodes) June 10 2007

Adj file format desription

There are two types of lines, "LINK" lines and node lines. Link lines look like:

Link S907_N_U:130.245.145.153 -- R1785_M_C:130.245.128.9 : RR

Saying there is a link from node "S907_N_U" on its 130.245.145.153 interface to node R1785_M_C on its 130.245.128.9 interface, and it was inferred by RR.

The node identifiers have meaning. They are of the form < nodetype>< unique id>< annotations> where annotations indidicate all sorts of information including RR implementation type. The "nodetype" is one of:

E: End-host (destination)
H: Hidden (probably via MPLS)
N: NAT
R: Router
S: Source (nodes that are both sources and end-hosts are non-deterministically assigned either source or endhost)

The "unique id" is just a number to assign to that node type.

And there are many possible annotations, here is a partial key:

A: Cisco/Departing RR type
B: Juniper/Arriving RR type
C: Linux/Mixed RR type
M: inferred indirectly; direct probe missing, e.g., could be an anonymous router
N: Not implemented RR type
U: unknown type (but might be identified later)

The last line of the Link statement (where it says "RR" in the example above) is what technique was used to infer that link, and can be any of:

"RR": This link was infered from record route and traceroute together; outgoing and incoming IPs are specificed
"TR": From TTL-limited probes (traceroute); lower confidence link; the IP addresses are the incoming interfaces of each router
"STR": From record route alone (no traceroute information): the outgoing or loopback interface of each router is listed
"UNKNOWN": Links that are listed as "UNKNOWN" do not actually exist and should be ignored. They are used for debugging purposes when a trace does not actually reach the intended destination, i.e., on a trace from S to D we learn r1,r2, r3, but after that we hit a firewall and don't know the path from r3 to D, we add a "UNKNOWN" link between r3 and D. All unknown links should be removed from published topologies (only listed here if we made a mistake).

There are also node statements for each "nodetype" that look like this:

Router R1540_A_U_NOTOFFBY1L_LAYER2 nAlly=2 202.112.54.254 202.112.1.195

This indicates node "R1540" has two aliases 202.112.54.254 202.112.1.195, and that it is of RR type Cisco ("A") and has the NOTOFFBY1L and LAYER2 annotations.

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