Presentation on theme: "Dongkee LEE 1 An Analysis of BGP Multiple Origin AS (MOAS) Conflicts Xiaoliang Zhao, et al."— Presentation transcript:
Dongkee LEE 1 An Analysis of BGP Multiple Origin AS (MOAS) Conflicts Xiaoliang Zhao, et al.
Dongkee LEE Motivation Classifications of MOAS conflicts. Results Possible explanations for MOAS.
Dongkee LEE The last AS in an AS path should be the origin of the BGP routes. Suppose prefix ‘d’ is associated with AS paths, asp1 = (p 1, p 2, … p n ), asp2 = (p 1, p 2, … p m ) If p n != q m : MOAS conflict occurs. MOAS could be the result of a ‘fault’ or an ‘attack’. What are the reason for MOAS conflicts and What are the impacts ?”
Dongkee LEE Classification of MOAS prefix ‘d’, asp1 = (p 1, p 2, … p n ), asp2 = (p 1, p 2, … p m ) OrigTranAS: p n = q j (j < m) AS P n announces itself as the origin AS and as a transit AS. SplitView: p i = q j (i < n, j < m) AS P i announces different routes to different neighbors. DistinctPaths: p n = q j (for all i in [1..n], j in [1..m] ) There are two totally different routes for the prefix ‘d’.
Dongkee LEE Oregon RouteViews data. Total Number of MOAS Conflicts. Overall conflicts were observed over 1279 days. Duration of MOAS Conflicts conflicts
Dongkee LEE Distribution of MOAS Conflicts
Dongkee LEE Distribution of MOAS classes
Dongkee LEE Causes of MOAS conflicts – (1) Exchange Point Addresses. Prefix associated with an exchange point is directly reachable from all the ASes, at the exchange point. 30 out of prefixes. Multi-homing without BGP.
Dongkee LEE Causes of MOAS conflicts – (2) Multi-homing with Private AS Numbers. AS number Substitution on Egress (ASE). Anycast addresses. Anycast address is intended to originate from multiple ASes. Faulty or Malicious Configurations.