Software Defined Networks
Technology Briefing
Software Defined Networks (SDNs) use vendor-neutral open protocols to provision services across
different types of commonly used switches and routers. Abstracting the proprietary nature of the
network infrastructure in this way results in the virtualisation of the network. Control of network
devices is both unified and centralised, allowing numerous proprietary management tools to be re-
placed by a single all-encompassing network management system that controls all network equip-
ment in exactly the same way. With the advent of SDN support in
Q-NET™
, the benefits enjoyed by
the wider IT world are now being brought to satellite networks.
‘Satellite modems are just another network
device, performing many of the same
functions as an Ethernet switch or router.
As SDN networks become commonplace, we
anticipate the coming together of the
satellite industry to create an open
standard for controlling the remaining non
-IP functions of satellite modems and other
satellite equipment, taking the concept of
satellite SDNs to an entirely new level.’
Colin Mackay, Vice President of Engineering
Q-NET™
Satellite Network Solution
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www.paradisedata.com 217132A Issued 4 October 2018
OVERVIEW
SDNs are highly programmable, with a centralised control system that decouples decisions about
how the network is managed from the routine task of handling specific user packets on a particular
device. As a result, SDNs fundamentally change how networks are architected and how they deliver
network services. SDNs are part of a wider move to virtualise services and applications, such as
Software As A Service (SAAS), Infrastructure As A Service (IAAS), etc. Network Function Virtualisation
(NFV) is an optional complementary technology that can be used to migrate specific network func-
tions such as load balancing and firewalls from dedicated appliances to software running on stand-
ard servers, with the resulting functions and resources then being managed using SDN techniques.
As explained in this whitepaper, the growing shift to SDNs is set to apply as much to satellite net-
works as it does to terrestrial networks.
It is widely recognised that legacy networks have
serious limitations and are consequently unable
to readily meet the demands of modern user ap-
plications based on cloud and mobile computing.
SDNs virtualise the underlying network infra-
structure, creating flexible, scalable networks
that adapt dynamically to changing demands.
‘Legacy networks, built using equipment
from multiple vendors, each with its own
proprietary control system, are highly
fragmented and difficult to manage’
SDN networks create a clear separation of con-
trol and data processing.
High-level network management involves tasks
such as network discovery, the setting up of for-
warding rules, computation of routes and gath-
ering of metrics.
The lower-level function of the network devices
by contrast is to implement the rules passed to
them from the control system in order to pro-
cess user traffic in the appropriate way.
By separating high-level control from the un-
derlying network packet processing operations, a
global network view becomes possible through a
centralised control system. In the process, the
network operator also gains vendor independ-
ence and provisioning and deployment of new
services becomes much easier.
Network high-level control is provided by an
SDN Controller
, which is an open-source or ven-
dor-specific software application that runs on
standard hardware. The SDN controller is itself
capable of being programmed by higher level
applications with business-level network policies
(covering security, access, SLA requirements,
etc.). The controller then converts these policies
into instructions for the individual network ap-
pliances, such as switches and satellite modems.
All communication from the SDN controller to
higher and lower level applications and equip-
ment uses open, standardised protocols.
All hardware network elements of
Q-NET™
sup-
port the
OpenFlow
protocol. OpenFlow is a
standardised SDN protocol that support the con-
figuration of network equipment at Layer 2.
OpenFlow maintains flow tables that consist of
flow entries that determine how packets belong-
ing to a particular flow will be processed and
forwarded. A flow consists of rules that identify
incoming packets as belonging to the flow, met-
rics for the flow and actions to be taken when a
packet belonging to the flow is received.
In addition,
Q-NET™
supports
sFlow
, which
compliments the use of OpenFlow, allowing the
collection and analysis of network metrics from
disparate network devices using a standardised
protocol. Like OpenFlow, sFlow is supported on
all Paradise modems,
allowing an out-of-the-
box SDN solution for network operators and ser-
vice providers who are creating their own SDN
satellite networks.
Q-NET™
systems can be provided as turnkey
rack solutions, complete with pre-configured
SDN-compliant Ethernet switches and routers.
‘We expect SDN concepts to evolve to allow
many satellite functions to be provided as
centrally controlled software services
running on standardised hardware, such as
Software Defined Radios’
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Q-NET™ SDN Whitepaper
Software Defined Network System Architecture
SEPERATING CONTROL FROM DATA
THE SDN CONTROLLER
SDN SUPPORT IN Q-NET
™