Connection Oriented Ethernet - InfoVista

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where the industry has been going
over the past five to seven years,
it’s all about network convergence,
and MPLS is the only technology
that allows you to converge
multiple protocols, including TDM,
Frame Relay, ATM, Ethernet and IP,
onto the same network. If you look
at PBB and if you look at Queue in
Queue and Ethernet in general, you
can implement Ethernet COE using
Ethernet pseudowires with MPLS.
But where I use the native technology,
I can use the MEF 8 standard
to emulate TDM over Ethernet, I
can run Ethernet services itself,
and run IP over Ethernet. On the
MPLS side, I can do all of that plus
I can get ATM emulation, Frame
Relay emulation, and if I need it,
High level Data Link Control (HDLC)
emulation.
If you look at something like the
mobile backhaul topic today, they
need to support multiple protocols:
TDM for the 2G services,
ATM for 3G services, and once
you go beyond 3G you’re starting
to look at Ethernet and IP. If I am
using MPLS, I can get all of that
off a single network and I have a
lot more flexibility to transport IP.
When I look at mobile backhaul for
LTE, some of the data that we have
seen in the past is, there’s no such
thing as a pure LTE site. The sites
are always going to be mixed. I can
get LTE over the Ethernet or I can
get it over IP and I have that flexibility
to do one or the other or both.
I have seen some cases where
they take L2VPN, which is your
Connection-Oriented Ethernet over
pseudowires in a VPLS scenario,
and I have seen folks ask for that
to access a Layer 3 VPN. If I have
a cell site that has 2G, 3G, and 4G,
I have to support TDM, ATM, and
Ethernet and IP. Well, there’s only
“If you look at where the industry has been going over the
past five to seven years, it’s all about network convergence,
and MPLS is the only technology that allows you to
converge multiple protocols... onto the same network.”
one technology that I know of that
does this and that’s MPLS. You can
debate whether or not it’s MPLS,
MPLS-TP, or some combination of
the two as well.
FT: One of the major initiatives
you are driving on the MPLS
end at the forum is the TR-221
specification, which defines
technical specifications for MPLS
in mobile backhaul networks.
What value does MPLS add in
the wireless backhaul network?
dS: TR-221 is pretty much the
embodiment of everything I just
mentioned. It provides the nodal
requirements for MPLS gear to
support the 2G TDM, 3G ATM and
3.5G and 4G IP using either Ethernet
or L3VPN. It gives the base
set of MPLS requirements for all
of that. It also addresses resiliency
and OAM.
FT: Can you talk about how the
service providers use of MPLS for
Ethernet?
dS: The service provider community
actually has a good deal of
interest in what we’re doing there
on several different levels. When it
comes to specifically to MPLS for
Carrier Ethernet networks they’re
looking at that to get a common
subset of functions to deliver Ethernet
services. They are using those
Ethernet services for mobile backhaul
and broadband access, so the
same document that we’re creating
for Carrier Ethernet services is being
picked up by another working group
in the Broadband Forum to support
the multiservice broadband architecture.
If you look at DSL in the old
days it was based on ATM, and now
it’s based on Ethernet. How are
you going to provide Ethernet? It’s
getting to the point where the DSL
link or the GPON link is the access
extension to the Metro Ethernet
network. I am getting my Ethernet
services from a DSL link, a GPON
link or I am getting my Ethernet
services over point-to-point fiber or
what we think of as point-to-point
copper. Everything is converging
down to a common network. Being
able to reuse that network for different
purposes, including how you
use that network to deliver triple
play services, but also use the same
network for mobile backhaul.
FT: So, what’s next on the horizon
at the forum as it relates to
MPLS/Ethernet-based wireless
backhaul?
dS: If you look at the work from
the Next Generation Mobile Networks
(NGNM) industry group,
they are starting to look at taking
macrocells and dividing them
down into smaller cells to make
better use of the wireless spectrum.
When you do that you don’t
have a 250-foot tower, but instead
have a small device hanging from
a ceiling in a shopping mall. What
does that architecture look like and
how does that change the mobile
backhaul perspective?
That’s actually something
we’re looking at now. We put out
TR-221, which is dealing with the
macrocell base stations, but now
we are working on an addendum
to that specification to do two
things. One, there were a number
of things in TR-221 that weren’t
quite mature for us to reference,
but those things have cleared and
now we’ll put out the corresponding
reference. The second thing
is we’re doing is looking at this
NGNM initiative around small cells
and looking at how that changes
mobile backhaul. Right now, we’re
looking at it and seeing it as a
necessary evolution to what’s happening
in mobile backhaul. You’ll
see things like the access used to
be P2P fiber or a microwave link
running Ethernet or TDM, but now
it could be a VDSL2 link. You have
to be able to put that thing on a
light pole, so you won’t be deploying
a large router next to it but
rather will run a DSL link to it. I will
get my Ethernet backhaul any way
I can by whatever access possible
that’s cost effective. That’s probably
true of any Ethernet service.
Whether I’m serving a house or
serving an enterprise, I am going
to use whatever access technology
I can that’s most cost effective. l
Q&A: Ralph Santitoro, founding
member and Director of the Metro
Ethernet Forum (MEF)
� In considering a path to
Connection-Oriented Ethernet
(COE), Ralph Santitoro,
founding member and director
of the Metro Ethernet Forum
(MEF) is quick to point out that
COE is not just based on one
standard, but rather a collection
of standards. Santitoro said that
much like ATM, “there’s no one
standard for COE, but rather
a collection of standards.”
This collection of standards
represents both an Ethernetcentric
and MPLS-centric approach to COE. Sean Buckley,
Senior Editor of FierceTelecom, sat down with Santitoro to
discuss the merits of both approaches and their role in the
next-gen telecom network.
FierceTelecom: To start, can
you give an overview of
what’s driving the need for
the Ethernet-centric approach
to COE?
ralph Santitoro: If you look at
what the most popular Ethernet
services are right now, they
are all point-to-point services.
Those are used for lots of different
things, including wireless
backhaul, data center interconnect,
and site-to-site VPNs. You
also have infrastructure applications
like broadband backhaul
for telcos’ DSLAMs (digital
subscriber line access multiplexers),
PON (passive optical
network) devices, and CMTS
(cable modem termination
systems) for cable operators’
DOCSIS systems. The reason
why I wanted to paint that picture
is that point-to-point rules
in WAN (Wide Area Networking)
and also for infrastructure
services like backhaul. COE was
created to have a packet friendly
version of that service.
FT: What is the state of the
COE market and what’s
driving service providers to
it?
rS: Even though COE has been
around for about 10 years, it’s
finally starting to see a lot of
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