2. White Paper: Passive Optical LAN Solution (POLS) 1
Introduction:
The rapid growth of bandwidth requirements for triple play services of voice, video and data are
causing the Local Area Network (LAN) to evolve mainly for large businesses and organizations. To
meet these requirements, enterprises are turning to Gigabit Passive Optical Networks (GPON) based
Passive Optical LAN (POL) solutions for a change to either an existing enterprise site or a new
enterprise site. It is called passive because there is no need for active electronics. Passive Optical
LANs provide enormous value to enterprises without forcing them to alter how they do business,
while existing services provided by their LAN remain the same with no change to core and user
devices. The basis of POL is the GPON technology which is a point-to-multipoint network
architecture that is now being implemented to provide a fiber-to-the-desktop solution in which
unpowered (hence passive) optical splitters are used to enable a single optical fiber to serve multiple
end points with multiple services. Passive Optical LAN (POL) solutions are implementations of
GPON technology platforms that have been optimized for enterprise LAN environments.
The Passive Optical LAN (POL) technological approach for enterprise businesses significantly
improves energy efficiency and reduce capital and operating expenses while improving the security
and reliability of their networks. It provides the environmentally responsible ("green") enterprises with
less energy consumptions and space requirements because a design with fewer active network
elements uses less energy consumption and less floor space. It also reduces the work of maintaining,
operating, and managing the enterprise LAN. This future-proofs the enterprises network infrastructure
while realizing all of the benefits of converging their networked services, including voice, video,
wireless access, security, surveillance, building environmental controls and building automation with
Power over Ethernet (PoE) where needed.
This white paper explains how Passive Optical LANs can benefit businesses and organizations
solve their evolving local area networks compared to traditional Active Ethernet LANs while
significantly cutting CapEx and OpEx, energy and space requirements.
Passive Optical LAN (POL):
POL is based on proven Gigabit Passive Optical Network (GPON) technology that is being
deployed by leading service providers around the world. POL provides enterprises with fiber optic
connectivity to any Ethernet end point such as end user devices, access points and security controllers,
application servers and printers. POL greatly simplifies the enterprise LAN by replacing copper based
cables and active devices in the traditional LAN setting with fiber optic equipment. POL technology
uses single mode type of fiber, which is necessary to enable wave division multiplexing of upstream
and downstream signals on a single fiber. It also incorporates the use of passive optical splitters
located anywhere between the main equipment or optical line terminal (OLT) and workgroup
terminals, also known as optical network terminals (ONTs). Note that the POL application can be
designed over a 20 km (about 12 miles) distance. The passive optical splitters serve to branch the
signal from one PON port on the OLT. In August 2012, the Telecommunications Industry Association
(TIA) published Addendum 2 to the ANSI/TIA 568-C.0 Generic Telecommunications Cabling for
Customer Premises. In this addendum, the TIA generic cabling standards have been updated to support
single mode fiber PON applications for the LAN.
3. White Paper: Passive Optical LAN Solution (POLS) 2
Passive Optical LAN (POL) vs Active Ethernet LAN:
Architecture:
Comparing the configurations of a traditional copper-based Active Ethernet LAN and a Passive
Optical LAN network helps to illustrate more clearly the architectural differences between the two
technologies:
On the left: An Ethernet LAN requires multiple cable runs and numerous active hardware that
takes up precious space and consumes costly energy. In a traditional Active Ethernet LAN, a router in
the top-most layer (Core Layer) links to the campus or building aggregation switches (Distribution
Layer) below. The distribution switches connect down to the Access Layer switches in the
communications closets. Copper cables extend from the communications closets to the users.
On the right: A passive optical LAN simplifies installation and operation and reduces expenses
by eliminating the need for redundant cable and switching/routing equipment. In a Passive Optical
LAN solution, the router is retained in the top-most layer and the Optical Line Terminal (OLT) serves
the same purpose as the campus aggregation switches. The building aggregation switching is
accomplished by the 1x32 (or 2x32 for equipment redundancy and fiber route diversity) optical
splitter, which is a passive device so there are no power requirements, little management while being
highly reliable. The Optical Network Terminals (ONTs) provide connectivity to the users and end
devices. POL technology cuts back on floor, rack and closet space. Reduction in floor space lowers
operating expenses by reducing overhead costs, such as space and HVAC. In addition, the smaller
4. White Paper: Passive Optical LAN Solution (POLS) 3
footprint associated with Passive Optical LAN technology enables next-generation performance and
services in smaller communication closets.
No client or PC reconfiguration is required when upgrading from active- Ethernet to a PON
infrastructure. Enterprises also have the flexibility to deploy an Passive Optical LAN in a fiber-to-the-
desktop topology. A splitter-equipped fiber distribution hub (FDH) on each floor routes the fiber to the
desktop ONTs throughout the building. The Passive Optical LAN provides integrated Ethernet
bridging, VLAN capability required for network segmentation and user authentication and security
filtering. The ONT, which functions much like an Ethernet switch, makes it possible for an enterprise
to seamlessly replace an Ethernet-switched LAN.
Transmission Medium:
In terms of the transmission medium itself, fiber has numerous advantages over the copper cable.
In comparison to copper cable the fiber cable firstly is bend insensitive and flexible, the minimum
bend radius for fiber cable is 5-10 mm, depending on the type, compared to approximately 30 mm for
Category 6 copper cabling and up to 50 mm for Cat 6A. Secondly fiber cable has more robust pulling
tension as it has typically a 50 to 100 lbf pulling tension specification, compared to traditional copper
media, which is relatively delicate and specified to only 25 lbf tension. This 25 lbf limit is imposed in
order to safeguard the required twists of the copper conductor pairs, otherwise performance
degradation due to crosstalk and other parameters can occur. Thirdly fiber cable is small and
lightweight, typical fiber cables used for longer distribution runs are 2.9 mm or less in outer diameter,
compared to copper structured cabling, which is twice that for Cat 6 and more for Cat 6A. Fiber cable
weighs a fraction of copper cable. Fiber typically weighs four pounds per 1,000 feet, compared to 22
or 39 pounds per 1,000 feet for Cat 6 or Cat 6A, respectively. Additionally, fiber cable provides less
energy consumption, more bandwidth and reliable data security. Passive Optical LAN using fiber
cable is highly secure and produces no EMI radiation that is typically associated with traditional
copper-wired facilities, also fiber cable provides powerful security measures at the physical layer, data
layer, and at the user port to greatly reduce the potential for Denial of Service (DoS) or other malicious
attacks. Below table signifies further the use of fiber cable over copper cable:
Optical Fiber cable Copper cable
Capex Cost (2000 user
optical LAN)
≤ 1,000,000 SAR ≥ 3,750,000 SAR
Lifecycle 30-50 years 5 years
Distance 20 km's 100 meters
Weight (per 1000 ft.) 4 lbs. 39 lbs.
Energy Consumed 2 watts per user 10 watts per user
Maximum Bandwidth 100 Tbps 10 Gbps
Security Hard to tap, easy to alarm Emits EMI
As an example, let's consider a traditional Ethernet Category 6 copper structured cabling system
in a ten story building supporting 2500 Ethernet ports should require about 500,000 feet of copper
cable weighing about 24 lbs/1000' which equates to about 12,000 lbs total. (This estimate includes a
5. White Paper: Passive Optical LAN Solution (POLS) 4
small amount of fiber in the riser, and a large amount of horizontal copper cabling, and all copper
patch cords required). In comparison, 2500 Ethernet ports with POLS supported by fiber optic cabling
to work area outlets and fiber patch cords to the ONTs (which have four Ethernet ports each) requires
only about 150,000 feet of cable which weighs less than 5 lbs/1000' and equates to about 1200 lbs
total. (This estimate includes all fiber in the riser and in the horizontal, and the fiber and copper patch
cords to connect Ethernet end devices.) Overall, the POLs provides more than 90% savings in cabling
materials. In addition, significant savings are also gained in the cabling infrastructure support materials
(ladder rack, spaces, cable guides, etc.).
Installing a Single Mode Fiber (SMF) infrastructure virtually future-proofs your network. Since
SMF has been demonstrated to carry upto 100 Tbps of full duplex bandwidth, the next-generation
network upgrade will not impact the installed fiber distribution network, and enterprises will only need
to upgrade the active electronics at far ends. Hence fully supporting the next generation POL upgrades.
CapEx and OpEx:
When upgrading your network infrastructure, it is important to look at both the near-term and
long-term expenses. Today’s enterprise requires solutions that not only lower initial capital expenses,
but also reduce the total cost of ownership (TCO) for the network. Passive Optical LAN technology
enables the enterprise to significantly reduce the cabling infrastructure costs from the data center to the
user by significantly reducing the number of cable runs. The result is a decrease in overall operational
costs and network complexity.
The POL technology model supports multiple densities of Gigabit Ethernet, POTS and RF video.
This integrated approach provides the ability to connect building automation systems, security cameras
and building sensors all on the same infrastructure, thereby removing the requirement and expense of
separate transport systems across the campus for each technology. The POL infrastructure also
eliminates costly hardware within a network, such as remote switches, as well as their associated
provisioning cost, annual maintenance and software licensing fees. A Passive Optical LAN extends the
network lifecycle to 10 years or more. This approach enables gradual, more predictable costs for
bandwidth upgrades over the full 10-year period and modest ongoing maintenance costs associated
with fiber.
CapEx Overview
6. White Paper: Passive Optical LAN Solution (POLS) 5
Above CapEx depiction breaks out the capital expense for both scenarios between active and
passive network elements. Capital expense for active network elements is the major difference
between the two solutions for both scenarios—as its name implies, the POL has lower active network
element capital expense. However, it is perhaps surprising that the passive network element capital
expenses are somewhat higher for the Active Ethernet solution. The Active Ethernet solution has
slightly higher passive network element capital expenses than the POL due to its use of one CAT 6
lateral cable connection to every end-user port, while the POL employs one single mode fiber between
the riser closet and each ONT. Each ONT has four end user ports. This results in higher cost for the
lateral cable runs in the Active Ethernet solution when compared to POL.
OpEx Overview
Above depiction breaks down the individual elements of OpEx for each solution and each
scenario. Vendor service contracts are the single largest source of the OpEx advantage enjoyed by the
POL over the Active Ethernet. There are two underlying reasons for the POL’s large advantage. First,
vendor service contract costs are assessed according to the purchase price of each active network
element. Since the CapEx of Active Ethernet active network elements is much larger than that of the
POL service contract, costs are much larger. Second, enterprise Ethernet switches are very complex and
require extensive manufacturer support and frequent in the-field upgrades. In contrast, the POL uses
7. White Paper: Passive Optical LAN Solution (POLS) 6
GPON technology which has been designed for very large scale (tens of millions of ONTs) residential
deployments. Of necessity, GPON technology is de-signed to minimize both system vendor and end user
service and maintenance. The unit cost of POL ser-vice contracts is 55% less than for the Active
Ethernet.
The percentage savings in terms of Total Cost of Ownership (TCO) for POL over Active Ethernet are
shown below:
CapEx OpEx TCO
Single Dwelling Building 39% 52% 45%
Multiple Dwelling Building 41% 71% 54%
Market Outlook:
Saudi Arabia being a major player as an oil rich country in the middle eastern region enjoys the
highest GDP amongst all the GCC nations. With a population of 27 million, a large geographical area
and a per capita GDP of around 31,000 USD it holds huge potential for business. Information and
Communication Technology (ICT) projects are rolled out on large scales by government bodies, telecom
service providers and many international enterprises. The government has begun establishing six
economic cities and stadiums, large number of smart cities and multibillion USD metro rail projects
where telecommunications infrastructure forms a key part.
POL which is mainly suited for larger enterprises best fits into such large scale projects where
scalable and immediate cost savings are most realized and longer-term operational benefits of the
solutions can be gained. Verticals where POL best fits into include government offices/entities, large
hotels/resorts, educational institutions, hospitals, financial institutions, manufacturing industries,
airports, railway stations, stadiums and large enterprise businesses.
Conclusion:
Enterprises looking to upgrade or replace their network infrastructure are realizing the value of
Passive Optical LAN. Passive Optical LAN provides significant benefits without forcing enterprises to
alter what they are already doing or changing out the core and user devices. Businesses are saving
capital costs, on-going operational costs on energy with almost 50% reduction in energy consumption
and reduced physical footprint while exceeding green sustainability goals.
Deploying a Passive Optical LAN helps an enterprise future-proof their network infrastructure
while realizing all of the benefits of converged network services and providing choice of having
multiple dwelling buildings being served by just one telecom room. The Passive Optical LAN provides
solutions that furnish high bandwidth while increasing the security and reliability of existing networks.
Hence the resulting network based on POL technology is a better solution than the alternative for the
enterprise LAN.
