The Cost of QoS Support in Edge Devices: An Experimental Study

             Roch Guerin  Ping Pan  Vinod Peris
              IBM T. J. Watson Research Center
             {guerin,pan,vperis}@watson.ibm.com
             
                  Liang Li, Steve Nadas
          IBM Corp., Networking Hardware Division
                  {lli,nadas@us.ibm.com}


Abstract:

This paper investigates the problem of making QoS guarantees
available in access devices such as edge routers, that are commonly
deployed in today's IP networks.  The introduction of new
capabilities such as QoS needs to take place, at least initially,
within the constraints imposed by the limitations and the
architecture of these existing systems.  It is, therefore, important
to identify possible solutions that can deliver the desired
functional enhancements without impacting performance or requiring
major upgrades.  In this paper, we propose a specific design
approach which we explore by carrying out a complete implementation,
whose performance we then evaluate in the context of an experimental
testbed.  The results of our experiments indicate that a reasonable
level of service differentiation, i.e., rate and delay guarantees,
can be provided with a minimal impact on the raw packet forwarding
performance of edge devices.  This provides some initial evidences
that as the Internet backbone is upgraded to support QoS guarantees,
a similar and necessary enhancement can also be implemented rapidly
and effectively at the edge of the backbone.