Article,

Revealing MPLS tunnels obscured from traceroute

, , , and .
ACM SIGCOMM Computer Communication Review, 42 (2): 87–93 (March 2012)
DOI: 10.1145/2185376.2185388

Abstract

Operators have deployed Multiprotocol Label Switching (MPLS) in the Internet for over a decade. However, its impact on Internet topology measurements is not well known, and it is possible for some MPLS configurations to lead to false router-level links in maps derived from traceroute data. In this paper, we introduce a measurement-based classification of MPLS tunnels, identifying tunnels where IP hops are revealed but not explicitly tagged as label switching routers, as well as tunnels that obscure the underlying path. Using a large-scale dataset we collected, we show that paths frequently cross MPLS tunnels in today's Internet: in our data, at least 30% of the paths we tested traverse an MPLS tunnel. We also propose and evaluate several methods to reveal MPLS tunnels that are not explicitly flagged as such: we discover that their fraction is significant (up to half the explicit tunnel quantity) but most of them do not obscure IP-level topology discovery.

Tags

Users

  • @tabularii
  • @jaeschke
  • @dblp

Comments and Reviews