IEEE Communications Magazine - June 2017 - page 16

IEEE Communications Magazine • June 2017
etworking and communications systems are currently
undergoing a substantive transformation on several
fronts, promising substantially lower cost, simplified
operations, and dramatically faster innovation cycles as tradi-
tional barriers to the deployment of innovations are removed.
Where in the past networking functions were predominantly
implemented using purpose-built hardware, custom proto-
cols, and firmware images, those networking functions are
increasingly instantiated through software that is abstract-
ed from hardware, freely programmable, and relying on
algorithmic invocation of generic application programming
interfaces (APIs). This transformation is best summarized as
“softwarization” of the network, which is, in turn, realized
through advances in networking software. These advanc-
es are multifaceted and occur in many areas, ranging from
virtualization of networking functions and network slicing
to new network deployment models that allow for logical
centralization, distribution, and the right placement of control
functions, from greater programmability and extensibility of
networking devices to the re-emergence of programmable
networks and over-the-top services, from new network inter-
faces to open source platforms and development toolkits,
and more.
This Feature Topic features six articles that are exemplary
of this transformation, providing an excellent cross-section
across these facets. First, “NFV Orchestration Framework
Addressing SFC Challenges” by Marouen Mechtri, Chaima
Ghribi, Oussama Soualah, and Djamal Zeghlache presents
an end-end-end framework that is geared toward the orches-
tration of service function chains involving virtualized net-
work functions. The framework provides a great example
of work that involves conceptually centralized platforms for
control and orchestration that leverage both global network
visibility as well as new interfaces, in this case to control vir-
tualized functions and compose them into service function
chains to provide networking services.
While many efforts in network softwarization and spe-
cifically in software-defined networks are geared toward
extracting intelligence from networks to centralize control
functions that were formerly distributed, other approaches
are emerging that aim to move certain functions back toward
the network edge. Placing functions at the edge can have
advantages with regard to scaling as well as performance of
locally closed control loops; it can be particularly attractive
for applications that require only limited coordination and
visibility that does not extend beyond the edge. This theme
is exemplified in “Container Network Functions: Bringing
NFV to the Network Edge” by Richard Cziva and Dimitrios
Pezaros. This article also highlights the rise of containers as
a virtualization technology that has considerable advantages
over traditional VMs in many deployment scenarios.
The third article, “Programmable Overlays via Ope-
nOverlayRouter” by Alberto Rodriguez-Natal, Jordi Paillisse,
Florin Coras, Albert Lopez-Bresco, Lorand Jakab, Marc Por-
toles-Comeras, Preethi Natarajan, Vina Ermagan, David Meyer,
Dino Farinacci, Fabio Maino, and Albert Cabellos-Aparicio,
turns our attention toward advances in networking software
with regard to the ability to program overlays on top of exist-
ing networks. Here the authors leverage LISP, a technology
used to decouple the concept of identifiers to uniquely iden-
tify a system from the concept of locators used for purposes
of routing, and introduce an open source platform with the
purpose of programming LISP-based network overlays.
Advances in networking software provide developers with
great power to program network behavior, but with great
power comes great responsibility. One aspect that develop-
ers need to confront is how to deal with rainy day scenarios,
exceptions, and race conditions. In this regard, “Garbage
Collection of Forwarding Rules in Software-Defined Net-
works” by Md Tanvir Ishtaique ul Huque, Guillaume Jour-
jon, and Vincent Gramoli presents a system that deals with
one such aspect, the impact of reprogramming of forward-
ing rules in a network. The article describes implications of
reprogramming flow tables in an SDN with regard to race
conditions in the forwarding of packets that are in transit and
the considerations required to conduct orderly cleanup and
removal of prior forwarding rules.
Next, “NEAT: A Platform- and Protocol-Independent Inter-
net Transport API” by Naeem Khademi, David Ros, Michael
Welzl, Zdravko Bozakov, Anna Brunstrom, Gorry Fairhurst,
Karl-Johan Grinnemo, David Hayes, Per Hurtig, Tom Jones,
Simone Mangiante, Michael Tüxen, and Felix Weinrank cov-
Alexander Clemm
Alex Galis
Luciano Paschoal Gaspary
Phil Laplante
Filip De Turck
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