SYSTIMAX® BULLET
The Importance Of Architecture When Planning A Cabling Solution
A cabling system may require a balance of both copper and fiber to cost
effectively meet today's needs and support the high bandwidth applications
of the future, such as multimedia and full motion video. Rapidly evolving
applications and technologies are drastically increasing the speed and
volume of traffic on LAN/WAN networks. Ensuring that your cabling
solution is designed to accommodate the higher transmission rates
associated with these evolving bandwidth intensive applications is critical.
Due to the versatility and wide range of applications support, Avaya have
pioneered the development of UTP/fiber cabling systems to satisfy virtually
all of a customers' network and building infrastructure needs. In addition to
the performance of the cabling solution itself, the right cabling architecture
needs to be chosen to optimize the investment and return for the particular
building environment. Balancing cabling system cost versus the
electronics, and also the ongoing management and flexibility of the
solution is a key part of effective cabling infrastructure design.
There are three main cabling architectures that are commonly used for
structured cabling systems. These are the traditional 2-level hierarchical
star, the centralized cross-connect and the zone wiring. The traditional 2level hierarchical star architecture is the normal standards recommended
architecture, while the others are more oriented to particular applications
and environments.
Each of these architectures is described in greater detail below.
Hierarchical Star
The 2 level hierarchical star configuration is the standard cabling topology
followed by International and North American standards. The concept is to
limit administration points to a maximum of two so that the cabling
infrastructure can be easily maintained. The two administration points are
the equipment room and the telecommunications closet. Electronics can
be located in both the equipment room and telecommunications closets.
Backbone cabling, whether it be copper of fiber depending on the
application, interconnects the equipment rooms and closets (Statistics
show that vast majority of building backbones are less than 300m) while
horizontal cabling runs from the telecommunications closet to the work
areas (maximum length 100 meters including all cords). This architecture
has been widely accepted by the building industry, the cabling industry and
applications developers. It is the benchmark to compare other
architectures to.
Centralized Cross-Connect
Centralized cross-connect, also known as single point administration, is an
optional architecture that was introduced to the standards by the fiber
cabling industry in an effort to make fiber to the desk a more attractive
solution. In this architecture, the telecommunications closet does not
contain active electronics. This closet is only a pull-though point, a splice
point, or a interconnect/cross-connect point between the horizontal and
riser/backbone cabling. The maximum length of the combined horizontal
and backbone/riser cabling is 300m including all cords. Although this
length is less than the total length (horizontal plus backbone/riser)
supported by the hierarchical star, it is within the length requirements of
most buildings and therefore not a major concern. If we assume the
average horizontal length is 50 meters, then based on several surveys
about 70% of combined horizontal plus backbone/riser lengths are 300m
or less. The extended cabling lengths make this architecture a viable LAN
option for fiber. The main goal of the centralized cross-connect architecture
is to facilitate collapsed backbones where the hubs/switches are all within
one location (the backbone connection is actually just a backplane within
the hub or a cord interconnecting stacked hubs). This facilitates fewer total
administration points and the use of larger hubs.
One can conclude that centralized cross-connects provide a number of
different advantages likely to be appealing to different customers. This
architecture can be an effective tool for positioning Fiber to the Desk as an
alternative to the hierarchical star.
Zone Cabling
Zone cabing is to a certain degree the opposite of centralized cabling. It
adds an extra connection in the horizontal to allow for rearrangements of
open office spaces. The concept here is to reduce the ongoing
maintenance costs when reconfiguring open office spaces. Instead of
abandoning/replacing all horizontal cabling when modular furniture clusters
are rearranged, only the portion in the modular furniture clusters (between
the outlets and the consolidation point or "extra connection") needs to be
replaced. Reconfiguration is much simpler, lower cost, and less
disruptive. Churn rates are often stated as being up to 100% per year
(although this applies to people moving, not offices being reconfigured)
thereby justifying the additional up-front cost of extra connections. With the
apparent market move towards open offices, this type of architecture will
continue to grow.
With SYSTIMAX SCS, customers have enhanced design freedom above
and beyond the standards in order to fully reap the benefits of these
architectures. One such enhancement is the allowance of more connectors
in the GigaSPEED XL channel (up to 6 connections versus the standards
based worst case of 4). For fiber, enhanced performance and design
freedom is also allowed with more embedded connectors for the
LazrSPEED LC channel.
Reasons for wanting this freedom may be that the customer likes to keep
their electronics in secure cabinets and interconnect the ports to dedicated
external patch panels. These patch panels are in turn connected to regular
cross-connect fields which means a total of 3 connections in the equipment
room/ telecommunications closet. Other reasons for 3 connections near
the work area is to allow additional flexibility when disconnecting work area
panels for re-arrangement. The additional connector would be located
where an individual work area panel is joined to the furniture distribution
pathway. The consolidation point will be at the other end of the distribution
pathway for a total of 3 connections (consolidation point connection,
furniture distribution pathway connection, and telecommunications outlet
connection).
Support for additional connectors in both fiber and copper channels is an
additional benefit that SYSTIMAX SCS supports by going beyond the
standards.
Cabling Selection
By choosing UTP and fiber optics as the media for the cabling solution,
support for the widest range of architectures is possible in the most
effective manner. For many users, a combination of advanced UTP cable
and Multimode/Singlemode Fiber is the best choice. Both support a wide
variety of applications, are specified as media for emerging high speed
LANs, and meet the specifications for virtually all cabling standards.
In the past, copper was ideally suited to lower speed applications while
fiber was best used for high speed, longer distance, and securitydependent applications. Today, high quality twisted pair copper and fiber
optic cabling system infrastructures overlap in capability up to Gbps data
rates.
Copper or Fiber to the Desk - Which Is The "Right Choice"?
Network providers are often faced with the question of whether to install an
unshielded twisted pair (UTP) copper or multimode fiber cabling system to
the desktop. Unfortunately, there is not a clearly defined answer to this
question. Most private networks require a mixture of both media to create
the most cost-effective networks for voice and data across the horizontal
and backbone segments of the network. High performance category 5e
and 6 UTP, such as Avaya's PowerSum and GigaSPEED XL solutions
respectively, provides the lowest initial cost for today's Local Area
Networks (LANs) up to rates of 1Gbps. Fiber-based networks can reduce
recurring operational charges and clearly have higher performance,
however with the introduction of Category 6 systems such as GigaSPEED
XL, the capabilities of UTP cabling have been substantially increased,
pushing out the move to fiber to the desk top.
Futureproofing the Backbone for 10Gbps
The near-term focus for IT managers is provisioning sufficient backbone
bandwidth capability, both equipment and infrastructure, to support the
proliferation of 10 & 100 Mbps and emerging 1Gbps Ethernet switching in
the horizontal. Because switches aggregate bandwidth from many users,
the backbone network that interconnects these switches must support
even higher rates. Thus, as 100- megabit speeds serve desktops, 1 gigabit
and even 10 gigabit speeds are needed in the backbone. 10 Gigabit
Ethernet equipment is now being developed and deployed to provide
solutions for combinations of multimode and singlemode fiber, based on
distance requirements for building riser or campus environments. And
while the 10 Gbps Ethernet standard might indicate a trend towards more
singlemode fiber in the premises backbone, the increasing deployment of
laser optimized multimode fiber solutions capable of 10 Gbps throughput
will delay the migration to high cost singlemode systems within buildings.
These multimode fibers allow for optimization of the cost, distance
supported and complexity of the optical components to best serve the
needs of the enterprise customer.
Fortunately, Avaya provides complete solutions for both fiber and copper
media. The choice of media depends largely on the customer's present
and future applications and business situations. A selection made without
considering these fundamentals has little chance of providing the best
solution. That is why it is important to understand not only the capabilities
of each media, but also specific customer needs.
Time to Plan
In order to determine which combination of twisted pair and/or fiber to
install and in which architecture, each customer must evaluate their
application needs, considering the various advantages of each cable type
and their relative importance. Cost, ease of installation, moves and
arrangements, current and anticipated applications, and the expected life
of the system are typically major decision factors. Environmental
considerations such as electrical noise and clean rooms may also
influence the decision, as well as building type, industry sector, and cabling
system ownership.
The anticipated need for low speed applications, short system lifetimes,
and low initial cost might lead to a predominantly twisted pair cabling
system. High speed application, extended distances, harsh environmental
conditions, and graphics intensive multimedia applications might lead to a
heavily fiber based system. Most systems will fall between these two
extremes.
Given that there is some overlap in the customer base and capabilities for
Category 5, 5e, and 6 cabling and multimode/singlemode fiber optic
cabling system infrastructures, an understanding of the customer's specific
requirements is needed to recommend the optimal cabling solution. The
decision will incorporate three phases - the definition of strategy, the
design of the system, the cost effectiveness of the choice.
For the definition of strategy, within budget restraints, each customer must
consider and prioritize the following:
*
The sophistication of their network applications
*
The kind of traffic expected on the various portions of the network
based on number of users, data transfer requirements of each user, LAN
architecture, etc.
*
The life expectancy of the network and cabling infrastructure
*
The frequency of moves and changes
*
The growth potential of their network over its expected life
*
Any adverse physical conditions in the customer's LAN
The design, architecture and specification of the system should include the
following:
*
Outlet density and presentation required
*
Resilience
*
Patch/jumper density
*
Wiring closet/space requirements
*
Media selection - UTP and /or fiber
*
Media considerations - performance, physical hazards
*
Manufacturers support and warranty
*
Cable containment including containment types (trunking, ducts,
cable tray), and containment design (size, safety, segregation)
*
Installation techniques and quality
*
Adherence to standards
*
Labeling, records and documentation
*
Testing and certification
*
Maintenance and services.
When evaluating cost effectiveness, the customer should always think in
terms of cost over the life of the cabling, rather than only the initial
installation cost and also compare the cost to electronic hardware which
will be replaced several times over the lifetime of the cabling. The lowest
initial cost is not always the cheapest in the long run, however once the
contract is placed it is difficult to change. Choose the right system first
time. Considering cost effectiveness should include the following:
*
Initial installation cost, ensuring it covers adequately the specification
to avoid unwanted extras and performance restrictions
*
Administration, the networks ability to be easily and inexpensively
reconfigured
*
Futureproofing, the ability to support ever increasing bandwidth and
data rates in the future
*
Maintenance, the effort required to keep the system operating
*
Life cycle value, the assurance of a warranty covering the
applications and hardware
SYSTIMAX SCS offer high performance copper and fiber cabling platforms
which will cost effectively allow enterprises to implement a wide variety of
applications and architectures. Customers need to be careful that in
selecting a solution today, they do not limit themselves in the future. With
advanced twisted pair and multimode fiber cable, connectors, and
apparatus, users can easily support all of their current applications, as well
as their emerging and future applications.