Simulating Large Networks using Fluid Flow Models (FFM)

Challenges

Networks, and the Internet in particular, have seen an exponential growth over the past several years. The growth is likely to continue for the foreseeable future, and understanding the behavior of this large system is of critical importance. A problem, however, is that the capabilities of simulators  fell behind the size of the Internet a few years ago. The gap has since widened, and is growing almost at the same rate as the network is growing.

People

Faculty and Staff

Graduate Student

Our Solution

Instead of simulating every packet of each individual connection in the network, we abstract out average behavior of TCP connection aggregates and AQM routers  into analytical fluid models. Solving the models numerically then yields performance metrics that are close to that of the original networks, thereby enabling an understanding of the key aspects of the performance of the networks. Details of our models and solutions can be found in our paper [1]. Stand-alone simulation code is available from Yong Liu ( yongliu@poly.edu ).

Integration with Packet-level Simulators

FFM can be integrated with other existing packet level simulators to conduct hybrid simulation. In such a hybrid simulation, FFM can be used to simulate back ground traffic in the core network and provide network delay and loss information to packet traffic running across the fluid core. Preliminary attempts to integrate FFM with ns-2 have proven successful [2]. Here are the integration code and documentation: [code], [documentation].

Now we are working on integrating FFM with different packet level simulators, e.g. Parallel/Distributed NS, QualNet, in a distributed fashion to simulate large networks.

Presentation

Presentation about FFM [Power Point (2.1M)], [Pdf (1.4M)]. It contains some examples of FFM simulation.

Publication

  1. Y. Liu, F. L. Presti, V. Misra, D. Towsley, Y. Gu
    2. "Fluid Models and Solutions for Large-Scale IP Networks"
    Proceedings of ACM SIGMETRICS 2003
    Available as UMass CMPSCI Technical Report.[pdf]
  2. Y. Gu, Y. Liu, D. Towsley
    3. "On Integrating Fluid Models with Packet Simulation"
    Proceedings of IEEE INFOCOM'04 [pdf]

Contacts to

Contact Yong Liu (yongliu@poly.edu), or Yu Gu (yugu@cs.umass.edu) for futher information.