Increasing Flexibility and Security at the Backbone Layer
Considered by many to be one of the more important orientations
in optical network development, ASON is now entering a more sophisticated
stage of application. Applications of intelligent Backbones by carriers
such as, Brazil Telemar, have proven that the adoption of ASON's
technology at the Backbone layer will greatly increase network flexibility
Current Problems Associated with Backbones
Seen as the lifeline of communication networks, the capacity,
efficiency, reliability and security of the Backbone network will
decide whether or not networks as a whole can perform and function
in a normal manner. Service operations become more diversified and
networking grows more complex when one combines different aspects
of broadband, internet and wireless use. Thus, the Backbone network
faces new challenges in various aspects such as; flexibility, security,
convenience in administration and maintenance, and so on.
With an extension of network scale and capacity, the stress placed
upon the capacity of the rings likewise increases exponentially.
So does the amount of services across the rings. Hence, the probability
for failures between two points on the same ring also arises, thus
allowing more services to be affected by failures in ring switching..Backbones
are usually links that cover much longer distances. Statistics reveal
that if fiber links are longer than the standard length, then the
more failures there will be (according to the GR-418 standard, the
reliability index for the fiber is 400FITs/km), which means a failure
occurs on a 285-kilometer fiber every year. According to 2004 statistics
from Chinese carriers, the failure rate of any given fiber is 473FITs/km,
which means a failure occurs on a 241-kilometer fiber every year.
Internet statistics from carriers in other parts of the world also
reveals that the failure rate for fibers in 2003 was 422FITs/km,
with a mean maintenance period of approximately 13 hours. Hence,
if more than two fiber breaks occur in the networks within a short
space of time, then the ring network would be paralyzed.
Backbone Flexibility Changes Brought About by ASON
Further development of the Backbone network will require huge
investments, thus, special attention should be focused on such issues
as flexibility, adaptability and enhancement of inter-operability.
Below, we will discuss in greater detail the various advantages
to be gained by using ASON technology.
- Improved Grooming Flexibility through Mesh Networking
Utilization of the intelligent Backbone scheme will enable the
network to become a flat MESH structure. Once this scheme is fully
adopted then services can then be groomed through straight routings
in any direction, which will completely break through the limits
of the current ring network and thus increase grooming efficiency.
- Increases Flexibility through End-to-End Automatic
With the adoption of the intelligent Backbone scheme will also
come the realization of an end-to-end automatic service provisioning
by signaling, which can greatly reduce the complexity of service
provisioning and error probability, thus increasing efficiency.
- Increases Application Flexibility of Optical Network
Equipment through Plug-and-Play Upgrades and Expansion
Intelligent equipment adopts OSPF and LMP protocols to automatically
detect and check new adjacent nodes and fiber resources. Therefore,
the use of this new type equipment will bring about a faster and
more convenient operation, while at the same time reducing the workload
and requirements for maintenance engineers, thus making it much
easier for carriers to accept this new technology. For it will not
only intelligentize the networks, but also simplify the operation.
- Increases Service Operating Flexibility through Continuous
A more convenient means of maintenance is achieved when using
intelligent optical networks, as opposed to using traditional equipment.
In other words, continuous in-service adjustments guarantee optimal
service routings, which makes it more convenient for carriers to
maintain and administrate their services. Such automatic service
adjustments can be made either through traffic engineering, or by
manual optimization of routings.
- Increases Bandwidth Utilization and Flexibility of
Optical Network Service Protection through Real-Time Automatic
The employment of intelligent equipment provides a means of automatic
restoration without the need to preserve protection bandwidth, which
is the most striking difference when compared to traditional SDH
equipment. For example, when a break occurs, this newly developed
service automatically searches for a real-time protection path.
In short, the essence of this type of mode is to share the protection
bandwidth, which greatly increases the bandwidth utilization of
existing networks, while at the same time providing a flexible and
practical restoration mechanism for services operating on optical
networks. It is also instrumental in decreasing the OPEX.
- Increases Interconnecting Flexibility via E-NNI Interface
The Optical Internetworking Forum (OIF) is highly committed to
the ongoing task of conducting cutting-edge research as it pertains
to network interoperability. In the rapidly developing field of
intelligent optical networks, the E-NNI protocol completely resolves
the problem of how to successfully interworking the equipment of
different vendors. For it not only increases the flexibility of
the interworking of different vendors, but also offers greater convenience
Statistics gathered from conducting E-NNI interoperability tests
of equipment from different optical network vendors worldwide in
2005, reveal that the application of E-NNI protocols, as it relates
to the interconnecting of equipment from different optical network
vendors, has gradually become more advanced and sophisticated. This
magnificent achievement was successfully demonstrated to the telecommunications
world in June 2005, during the Supercomm, which helped to imbue
customers worldwide with confidence in the interoperability and
large-scale application of ASON technology.
- Increases Operation Flexibility at the Optical Network
Customer Layer through Dynamic Bandwidth Application
Intelligent equipment is specifically designed to support a UNI
interface, thus allowing terminal users greater flexibly and more
dynamic applications of optical network equipment for bandwidth
resources. It also supports the BOD function, which enables carriers
greater opportunities for exploration and development of new service
modes, which in turn offers greater chances for profit growth through
the idea of the optical virtual private network (OVPN).
Improvement in Backbone Security to Be Brought About by
Generally speaking, the Backbones compose the basic carrier networks
of telecommunications. Therefore, if a break where to occur in the
Backbones it could result in heavy economic losses for carriers.
Hence, the need arises for carriers to adopt an effective way to
increase the reliability of the Backbone network. For areas where
frequent fiber breaks occur due to private land use, or other reasons,
an effective means is needed to improve network reliability.
- Increase in Backbone Reliability
Intelligent Backbones successfully combine both WDM and ASON technologies,
which enables them to employ perfect protection by tapping into
the restoration mechanism of the WDM wavelength protection and intelligent
attributes, thus greatly improving the security of the Backbone
This equipment is particularly designed with built-in intelligent
attributes that allow it to adopt MESH networking, which enables
it to support 1+1 protection and automatic restoration. Therefore,
in the event of multiple faults, overall services are not affected,
which greatly improves network security.
Telemar is the leading telecommunications carrier in Brazil, Telemar
currently has numerous fixed and mobile networks, which generates
a fairly high demand for real-time service commissioning. This poses
a problem in that it creates the need for an even higher requirement
for Telemar network construction, which should exhibit strong survivability,
support fast end-to-end commissioning, provide services at different
layers, and thus be able to amply meet the needs and demands of
It was in such a circumstance as this that Huawei Technologies
put forward its intelligent Backbone network solution. Telemar's
network currently covers 7 key cities which are situated on the
east coast of Brazil. Since 2004, its entire network has been operating
stably and successfully withstanding numerous trials of consecutive
The following figure illustrates Telemar's network reliability
after it employed Huawei's intelligent Backbones. Before the construction
of the intelligent Backbones, the monthly statistics for reliability
using traditional ring protection were about 99.99%. However, after
the construction of Huawei's intelligent Backbones, reliability
rose to 100% in all the statistical periods.