IEEE Communications Magazine - June 2017 - page 34

IEEE Communications Magazine • June 2017
32
0163-6804/17/$25.00 © 2017 IEEE
A
bstract
OpenOverlayRouter (OOR) is an open source
software router to deploy programmable overlay
networks. OOR leverages the Locator/ID Sepa-
ration Protocol (LISP) to map overlay identifiers
to underlay locators, and to dynamically tunnel
overlay traffic through the underlay network. LISP
overlay state exchange is complemented with
NETCONF remote configuration and VXLAN-
GPE encapsulation. OOR aims to offer a flexible,
portable, and extensible overlay solution via a
user-space implementation available for multiple
platforms (Linux, Android, and OpenWrt). In this
article, we describe the OOR software architec-
ture and how it overcomes the challenges asso-
ciated with a user-space LISP implementation.
Furthermore, we present an experimental evalu-
ation of OOR performance in relevant scenarios.
I
ntroduction
Overlay networks have been used over the years
to circumvent the constraints of physical net-
works. Overlays allow bypassing the limitations
of current deployments and enhancing network-
ing infrastructure without replacing the hardware
already in place. These networks have proved to
be useful for a broad range of use cases, such
as multicast [1], traffic engineering [2], resilient
networks [3], and peer-to-peer networking [4].
Furthermore, with the advent of software-defined
networking (SDN), overlays have become a tool
to enable SDN capabilities over legacy network
equipment [5, 6].
Among the different options to instantiate over-
lays, the Locator/ID Separation Protocol (LISP) [7]
has gained significant traction among industry and
academia [5, 6, 8–11, 14, 15]. Interestingly, LISP
offers a standard, inter-domain, and dynamic over-
lay that enables low capital expenditure (CAPEX)
innovation at the network layer [8]. LISP follows
a map-and-encap approach where overlay iden-
tifiers are mapped to underlay locators. Overlay
traffic is encapsulated into locator-based packets
and routed through the underlay. LISP leverag-
es a public database to store overlay-to-underlay
mappings and on a pull mechanism to retrieve
those mappings on demand from the data plane.
Therefore, LISP effectively decouples the control
and data planes, since control plane policies are
pushed to the database rather than to the data
plane. Forwarding elements reflect control poli-
cies on the data plane by pulling them from the
database. In that sense, LISP can be used as an
SDN southbound protocol to enable programma-
ble overlay networks [5].
In this article we present OpenOverlayRout-
er
1
(OOR), a community-driven project focused
on developing an open source software router
to deploy LISP-based overlays. Open sourced
under an Apache 2.0 license, OOR can run on
Linux computers, Android devices, and OpenWrt
2
home routers. OOR supports both LISP [7] and
LISP Mobile Node (LISP-MN) [9] (a lightweight
version of LISP intended for mobile devices)
for overlay state exchange, NETCONF — Inter-
net Engineering Task Force (IETF) Request for
Comments (RFC) 6241 — protocol for remote
management and configuration, and LISP and
VXLAN-GPE
3
formats for encapsulation. OOR is
a renaming of the LISPmob
4
project, the origi-
nal implementation of the LISP-MN specification,
after LISPmob grew in features and capabilities
over the years. From a minimal LISP-MN imple-
mentation, LISPmob evolved into a complete LISP
implementation, and from there to a compre-
hensive overlay solution that incorporates other
protocols beyond LISP, effectively becoming Ope-
nOverlayRouter.
OOR’s focus is on enabling network pro-
grammability at the edge, with special interest
in providing added value to end users. To that
end, OOR’s code runs entirely at the Linux user
space and has a common code base for all sup-
ported platforms. This software approach allows
the OOR community to have a strong focus on
flexibility, customization, and development of new
features. In this context, OOR represents a solid
base for research, innovation, and prototyping
of new overlay use cases. An example of OOR’s
success is that it is being used by LISP projects
in major SDN controllers: LispFlowMapping
5
in
OpenDayLight
6
and SBI LISP [10] in ONOS.
7
In what follows, we describe OOR’s software
architecture and components. We first give an
overview of the main architectural core ideas
behind its implementation and later delve into the
internals of its architecture (both control and data
Programmable Overlays via
OpenOverlayRouter
Alberto Rodriguez-Natal, Jordi Paillisse, Florin Coras, Albert Lopez-Bresco, Lorand Jakab, Marc Portoles-Comeras, Preethi Natarajan, Vina Ermagan,
David Meyer, Dino Farinacci, Fabio Maino, and Albert Cabellos-Aparicio
A
dvances
in
N
etworking
S
oftware
OpenOverlayRouter
(OOR) is an open source
software router to deploy
programmable overlay
networks. The authors
describe the OOR soft-
ware architecture and
how it overcomes the
challenges associated with
a user-space LISP imple-
mentation. They present
an experimental evalua-
tion of OOR performance
in relevant scenarios.
Alberto Rodriguez-Natal, Florin Coras, Lorand Jakab, Marc Portoles-Comeras, Preethi Natarajan, Vina Ermagan, and Fabio Maino are with Cisco Systems;
Jordi Paillisse, Albert Lopez-Bresco, and Albert Cabellos-Aparicio are with the Technical University of Catalonia; David Meyer is with Brocade Communication Sys-
tems; Dino Farinacci is with lispers.net.
1
2017.
2
accessed 13 March 2017]
3
accessed 13 March 2017.
4
March 2017.
5
3
March 2017.
6
accessed 13 March 2017.
7
accessed 13 March 2017.
Digital Object Identifier:
10.1109/MCOM.2017.1601056
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