Integrated Services in the Internet Architecture: an Overview
- State the problem the paper is trying to solve.
The main problem the memo is trying to solve is how to extend the Internet
architecture and protocols to provide integrated services, i.e. to support
real-time as well as the current non-real-time service of IP.
- State the main contribution of the paper: solving a new problem, proposing a
new algorithm, or presenting a new evaluation (analysis). If a new problem, why
was the problem important? Is the problem still important today? Will the
problem be important tomorrow? If a new algorithm or new
evaluation (analysis), what are the improvements over previous algorithms or
evaluations? How do they come up with the new algorithm or evaluation?
The main contribution of this memo is that it gives a detailed proposal of to
extend the Internet architecture and protocols to provide integrated services. The
extension is necessary to meet the growing need for real-time service for a
variety of new applications, including teleconferencing, remote seminars,
telescience, and distributed simulation. The problem is important today and will
continue to be important tommorow as the demand for real-service over the internet
increases. Their work is based on much discussion and research on Integrated
Services over the past few years.
- Summarize the (at most) 3 key main ideas (each in 1 sentence.)
The three 3 key main ideas are:
(1) Before real-time applications such as remote video, multimedia conferencing,
visualization, and virtual reality can be broadly used, the Internet
infrastructure must be modified to support real-time quality of service (QoS),
which provides some control over end-to-end packet delays.
(2) Network operators are requesting the ability to control the sharing of
bandwidth on a particular link among different traffic classes and this facility
is commonly called controlled link-sharing.
(3) The authors presents in their memo an IS extension of the Internet, real-time
service models, traffic control ( the forwarding algorithms used in routers ), and
RSVP, their design of a resource setup protocol compatible with the assumption of
their IS model.
- Critique the main contribution
- Rate the significance of the paper on a scale of 5
(breakthrough), 4 (significant contribution), 3 (modest contribution), 2
(incremental contribution), 1 (no contribution or negative contribution).
Explain your rating in a sentence or two.
I give this paper a rating of 4 because it presents a clear formulation and
proposal for a solution to a increasingly pervasive problem of how to expand the
Internet to support a variety of services. It also gives a comprehensive set of
features a solution to this problem should have and provide, which can be useful
even if their solution does not ultimately become the solution for providing them.
- Rate how convincing the methodology is: how do the authors justify the solution
approach or evaluation? Do the authors use arguments, analyses, experiments,
simulations, or a combination of them? Do the claims and conclusions follow from the
arguments, analyses or experiments? Are the assumptions realistic (at the time of the
research)? Are the assumptions still valid today? Are the experiments well designed?
Are there different experiments that would be more convincing? Are there other
alternatives the authors should have considered? (And, of course, is the paper free of
The authors' methodology was to present a number of solutions based on previous
and a model for bringing these solutions together and implementing them. Most of
the solutions it presents are argued for by appealing to reasons why they would be
useful and thus, should be included in their implementation. They also diagram how
the different components of their model should fit together and operate.
- What is the most important limitation of the approach?
The most important limitation of their approach was pointed out in B+98. In this
memo, the Blake et al. point out that the Integrated Services, RSVP model relies
upon traditional datagram forwarding in the default case, but allow sources and
receivers to exchange signaling messages, which establish additional packet
classification and fowarding state on each node along the path between them. In
the absence of state aggregation, the amount of state on each node scales in
proportion to the number of concurrent reservations, which can be potentially
large on high-speed links. The RSVP model also requires application support for
the RSVP signaling protocol. These limitations pose potential drawbacks to using
the author's RSVP protocol.
- What lessons should researchers and builders take away from this work. What
(if any) questions does this work leave open?
The lessons that researchers should take away from this work are that it seems
possible and viable to provide manageable and widespread integrated services on
the Internet. The memo provides a framework for doing so and a list for what
should potentially provided to manage and administer such a system. It should be
used a guideline for designing future systems.