OPINION SD-WAN
“My view is that costs saving are possible but, like most aspects of getting an SD-WAN,
highly dependent upon the use case.” Ian Hunter, Contributing Editor, Comms Business
So You Want an SD WAN?
Do you sometimes get the feeling that purveyors of SD WANs would have you believe that as well as cost
savings, instant provision of end point connections and infi nite adjustments of both bandwidth and class of
service? Claims they can also cure the common cold and arrange for Arsenal to win the Premier League seem
just a step away says Ian Hunter
If only it were so simple;
but before I have a go at
knocking over some of this
hyperbole I’d like to align
my current position to being one
of ‘this thing could work one
day given the right conditions
and con gurations, but it’s not
for everyone and right now SDWAN
is way over-hyped’.
I’ll start with the ‘instant
provisioning’ thing because
that’s the easiest killer feature
upon which to in ict a mortal
wound. I’ll make just two points,
either of which are individually
fatal blows.
Firstly, you have to recognise
that SD-WAN is an overlay
service that needs an underlay
service – the connectivity,
upon which to run the service.
ere are essentially two types
of SD-WAN provider; those
that provide the overlay service
– think in terms of a router or
virtual CPE type solutions and
there are those that provide a
‘complete solution’ – both the
overlay and underlay elements.
In the case of the overlay
only supplier, if the SD-WAN
controller cannot direct both
these elements that means there’s
no chance of instant provision
or bandwidth exibility. at
feature is in the wind because a
third party company controls the
underlying connectivity.
My second point here is
connectivity speci c. How can
you provision a node on your
network if there is no existing
connectivity? at’s quite a
common experience I would
say in an expanding enterprise
location roster.
Well, in our business there
are always work-arounds and
©Panupong-stock.adobe.com
this problem of no connectivity
is no exception. For xed
line connectivity, leased
line or internet, the instant
provisioning time is directly
proportional to the period it
takes a supplier to roll up and
connect you.
Your experience here will be
far greater that mine but I could
hazard a guess or three that it
would more than a few days. For
non- xed access there is the 4G
work-around, 5G would solve
the problem but right now… it’s
not an option. So, the short term
x is 4G closely followed by the
Openreach van arriving.
Whilst these work arounds
could provide a service of sorts,
4G is not
omnipresent
and
bandwidth
on the
internet
is both
shared and
dependent upon distance from
the local exchange. I hear you
say, ‘What about bre then?’ to
which I would say, you might
get lucky – but it’s still shared.
As for the promise of
in nitely turning up/down the
bandwidth volume control and
tweaking the class of service?
You can forget about that, and
in any case how would you do it
anyway – the underlay is in the
gift of a third party.
e cost savings argument
is perhaps more nebulous I feel.
My view is that costs saving are
possible but, like most aspects
of getting an SD-WAN, highly
dependent upon the use case. To
keep it simple though I would
say that if the client is entirely
based in the UK and was willing
to risk ‘going hybrid’ – laying
o a good percentage of the
required connectivity to the
internet, cost savings could be
made – but not approaching
those being universally claimed.
ink in terms of a three
year ROI cycle right now but
remember newer technology will
bring down price.
For the use case where a
client has a number of overseas
operations in an array of
countries and
continents the cost
savings bene ts
could end up
being negative
depending upon
all the di erent
local charges. Don’t
forget to add up all
the management
costs here either.
SD-WAN is
going to be use case
driven market for
the near term at least and the
best positioned suppliers right
now will, I feel, be those that
who o er that complete overlay
and underlay solution.
I’m really hoping for some
feedback on this article so please
don’t be shy – after all, as my
wife and diligent proof reader
often reminds me, what do I
know?
Come on the Gunners!
54 | Comms Business Magazine | March 2019 www.commsbusiness.co.uk
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