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The
user expectation of Internet use has moved from best-effort connectivity to
an expectation of reasonable performance & capacity for all types of
applications. QoS-sensitive applications like IPTV,
gaming, and VoIP could be offered over such a
converged IP broadband end-to-end network. Network service providers also
would like to support such applications effectively. They need to provision
their networks to meet the service level agreements (SLAs).
Customer experiences need to be protected and predictable despite network
failures and changes in demand as well as application mix.
Currently
there is a wide ranging debate on the issue of “network neutrality” which
involves both economic and technical aspects. One key aspect of the net
neutrality debate is whether best effort application traffic should be
carried along with other (so-called “premium”) traffic for which SLA
commitments have been made (or are expected, either explicitly or implicitly)
without differentiation. An assertion often made in this context is that
over-provisioning is an economically viable strategy due to the declining
cost of capacity, instead of incurring the complexity and operational costs
of running a differentiated-services network. Our study focuses on this
specific question within the larger debate. We compare a classless network
which is over-provisioned against an engineered network using per-class
queuing to offer Class-of-Service (CoS) (i.e.,
differentiated-service) and meet user expectations and SLAs.
In most situations a differentiated network can save significantly over a
classless network.
- M. Yuksel, K. K. Ramakrishnan, S. Kalyanaraman, J. D. Houle,
and R. Sadhvani, Value of
Supporting Class-of-Service in IP Backbones, (short paper) Proceedings of IEEE International
Workshop on Quality of Service (IWQoS), Chicago, IL,
June 2007.
Abstract: The desire or
ability of an ISP to provide differentiated service is a current hotly
debated topic. In this paper, we quantify the value of having
differentiated service (i.e., class-of-service (CoS))
support in an IP backbone. We compare the capacity requirements of a Diffserv environment providing service for
applications that require delay or loss assurances in comparison to a
network that provides classless (i.e., best-effort) service and still
has to meet the same performance assurances. Our modeling framework
first develops a link model that quantifies the Required Extra Capacity
(REC) in order for a classless link to provide the same level of
performance as experienced by premium class traffic passing through a
fixed capacity CoS link. We develop the REC
calculations for the cases when average delay or the average loss
probability is the target performance goal with Poisson or Markov
Modulated Poisson Process (MMPP) input traffic. Our primary contribution
is in quantifying the value of the CoS support in a network setting.
Presentation
- J. D. Houle, K. K. Ramakrishnan,
R. Sadhvani, M. Yuksel, and S. Kalyanaraman, The
Evolving Internet - Traffic, Engineering, and Roles, Proceedings of Research Conference on
Communication, Information and Internet Policy (TPRC), Arlington,
VA, September 2007.
Abstract: Entertainment
and real-time applications like voice-over-IP, medical telemetry,
network gaming and streaming video are quickly becoming prevalent
applications over packet-based communication networks. These
applications impose an extremely diverse set of network performance
requirements. Further, networks are also experiencing rapid growth in
the number of users and traffic per user. There have traditionally been two
canonical approaches to handling such needs: (i)
provide substantially increased bandwidth on the links to create
sufficient overall capacity in a best-effort network, or (ii) provide
class-based differentiated service to meet each application’s
performance requirements. The
current network-neutrality debate reflects the tension between providing
substantial additional capacity to meet the most demanding application
needs and search for a viable business model to fund this capacity
growth.
We examine three dimensions to lend insight to this ongoing debate. First, we focus on broad application
performance requirements and discuss traffic growth projections. Second, assuming a mix of emerging as
well as traditional applications, we develop queuing models for an IP
backbone to quantify the economies achievable with a differentiated
network compared to a best-effort network with enough capacity to
achieve the required performance.
Finally, we examine a variety of media delivery models to understand
the flexibility needed to achieve the objectives of sustainability and
customer expectations.
Presentation
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