Location:
NE43-516
Time:
1:00pm Monday
Organizer:
Archit Shah
ashah@mit.edu

Network Reading Group - Spring 2002

The Network Reading Group is a weekly forum for students and faculty to discuss current, interesting, and influential papers in the area of computer networks. At each meeting, the group will focus on one paper which the group members select. Papers with any connection to networking are fair game. The group's goal is to not only familiarize members with the current literature in the area of networks, but also to encourage members to meet others with similar interests, exchange ideas, and to stimulate new directions of research.

Food is provided!

If you would like to submit a suggestion for a paper, volunteer to lead a discussion, or subscribe to the netread mailing list, please send mail to ashah@mit.edu.

 
 

Upcoming Readings

5/20 Title: Some perspectives on the SIGCOMM 2002 Submissions, Reviews, and Decisions
  Speaker: Prof. Hari Balakrishnan

Past Readings

3/11 Title: The Origin of Power Laws in Internet Topolgies Revisited
  Authors: Qian Chen, Hyunscok Chang, Ramesh Govindan, Sugih Jamin, Scott Shenker, Walter Willinger
  Download: http://topology.eecs.umich.edu/archive/infocom02.ps
  Netread presenter: Archit Shah (ashah@mit.edu)
  Abstract:
  In a recent paper, Faloutsos et al. [1] found that the inter Autonomous System (AS) topology exhibits a power-law vertex degree distribution. This result was quite unexpected in the networking community and stirred significant interest in exploring the possible causes of this phenomenon. The work of Barabasi and Albert [2] and its application to network topology generation in the work of Medina et al. [3] have explored a promising class of models that yield strict power-law vertex degree distributions. In this paper, we re-examine the BGP measurements that form the basis for the results reported in [1]. We find that by their very nature (i.e., being strictly BGP-based), the data provides a very incomplete picture of Internet connectivity at the AS level. The AS connectivity maps constructed from this data (the original maps) typically miss 20--50% or even more of the physical links in AS maps constructed using additional sources (the extended maps). Subsequently, we find that while the vertex degree distributions resulting from the extended maps are heavy-tailed, they deviate significantly from a strict power law. Finally, we show that available historical data does not support the connectivity-based dynamics assumed in [2]. Together, our results suggest that the Internet topology at the AS level may well have developed over time following a very different set of growth processes than those proposed in [2].

3/18 Title: RFC3031 - Multiprotocol Label Switching Architecture
  Authors: E. Rosen, A. Viswanathan, and R. Callon
  Netread presenter: Joanna Kulik (jokulik@lcs.mit.edu)
  Download: http://www.ietf.org/rfc/rfc3031.txt
  Abstract:
  (Taken from the MPLS FAQ) MPLS stands for "Multiprotocol Label Switching". In an MPLS network, incoming packets are assigned a "label" by a "label edge router (LER)". Packets are forwarded along a "label switch path (LSP)" where each "label switch router (LSR)" makes forwarding decisions based solely on the contents of the label. At each hop, the LSR strips off the existing label and applies a new label which tells the next hop how to forward the packet. LSPs are established by network operators for a variety of purposes, such as to guarantee a certain level of performance, to route around network congestion, or to create IP tunnels for network-based virtual private networks. In many ways, LSPs are no different than circuit-switched paths in ATM or Frame Relay networks, except that they are not dependent on a particular Layer 2 technology. An LSP can be established that crosses multiple Layer 2 transports such as ATM, Frame Relay or Ethernet. Thus, one of the true promises of MPLS is the ability to create end-to-end circuits, with specific performance characteristics, across any type of transport medium, eliminating the need for overlay networks or Layer 2 only control mechanisms.

Other resources:

4/22 Title: Escrow Services and Incentives in Peer-to-Peer Networks
  Authors: B. Pinkas, B. Horne, and T. Sander
  Netread presenter: Steve Bauer (bauer@mit.edu)
  Download: ps pdf
  Abstract:
  Subscription-based service are currently receiving a lot of attention from the content industry as a viable business model for P2P content distribution. [...] We propose a system architecture that uses economic incentives instead of tamper resistance to motivate users to keep the content within the subscription community. The key technical contribution we make is to integrate a P2P file sharing service with an escrow service that reliably "pays" the party that is serving up the content. The payment itself can be realized in a number of ways, using "actual" money or bonus points such as frequent flyer miles. Moreover, our architecture facilitates trust between two unacquainted parties by offloading risk to a trusted third party, which can acquire a revenue stream by assuming this risk. [...]
4/29 Title: A Configurable and Extensible Transport Protocol
  Authors: Gary Wong (Arizona), Matti Hiltunen and Richard Schlichting (AT&T Labs - Research)
  Download: http://www.ieee-infocom.org/2001/paper/569.ps
  Netread presenter: Archit Shah (ashah@mit.edu)
  Abstract:
  The ability to configure transport protocols from collections of smaller software modules allows the characteristics of the protocol to be customized for a particular application or network technology. This paper describes an approach to building such customized protocols using Cactus, a system in which micro-protocols can be combined into a composite protocol that realizes the desired overall functionality. In contrast with similar systems, Cactus supports nonhierarchical module composition and event-driven execution [...]. This suite of micro-protocols has been implemented [...] with initial experimental results indicating that the ability to target the guarantees more precisely to the needs of the applications can in fact result in better performance.
5/6 Title: Understanding BGP Misconfigurations
  Authors: Ratul Mahajan, David Wetherall, Tom Anderson
  Download: http://www.cs.washington.edu/homes/ratul/bgp/bgp-misconfigs.ps
  Netread presenter: Xiaowei Yang (yxw@mit.edu)
  Abstract:
  It is well known that simple, accidental BGP configuration errors can disrupt Internet connectivity. Yet little is known about the frequency of misconfiguration or its causes, except for the few spectacular incidents of widespread outages. In this paper, we present the first quantitative study of BGP misconfiguration. Over a three week period, we analyzed routing table advertisements from 23 vantage points on the Internet backbone to detect incidents of misconfiguration. For each incident, we polled ISP operators involved to verify whether it was a misconfiguration, and to learn the cause of the incident. We also actively probed the Internet to determine the impact of misconfiguration on connectivity.
 

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