1. Observing the Evolution of Internet AS Topology

2. Data Sources Name Type #vantage points Historic RV+RIPE+Abilene+cernet
BGP RIBS + updates
~500
Since
Routeservers
RIBS
~60
Looking glasses
Neighbor Ases+traceroute
~200
Skitter
Traceroute
~20
Dimes
~12k
iPlane
~300
2006-7

3. Comparision between data sources
Period since
BGP
Skitter
Dimes
Total
111,122
74,741
111,372
Unique
45,386
28,170
35,521
Union
187,882
Common
30,548

4. BGP data

5. Accuracy of BGP timestamps
Picked 54 routers (37 ASes) with consistent data during the 3 yrs; splitted these routers in two sets, such that each ASN belonged to just one set:
Set0: 29 routers, 18 Ases, w/ 95,939 links
Set1: 25 routers, 19 Ases, w/ 99,122
Common links to Set0 and Set1: 91,804

6. Accuracy of BGP timestamps
Only about 10% of links’ timestamps are off, an effect of revelation process
Generally, BGP timestamps can be used as calibration points to evaluate accuracy of traceroute timestamps

7. Skitter data

8. Verifying Skitter timestamps
40,041 out of 97,216 skitter links appear in BGP monitors
About 10% of links appear first / disappear last in Skitter: an effect of revelation process in BGP
About 40% of links have same timestamp as in BGP
50% of links’ timestamps are off in Skitter

9. Dimes Data
Data available from Sept 23, 2004 to Nov 5, 2006

10. Verifying Dimes timestamps
Compared 25,261 links with BGP
Similar observations as Skitter data
Disappearance period is off x=0 because I’m missing a month of Dimes data (Nov 2006), therefore last_seen timestamps of live links are off by some days when compared to BGP