Interconnectivity: A typical application area for signaling monitoring Download

Interconnectivity: A typical application area for signaling monitoring
"I made three micro-blog posts while in Moscow and the operator charged me more
than RMB3,900 (USD600) for network access, which is enough to buy a new mobile
phone.” This microblog post by a girl named Jin Na was retweeted more than 7,400
times within 48 hours and received more than 2,600 comments, widely drawing public
attention. It turned out that the three posts Jin Na made while in Moscow used the
international roaming service, leading to a traffic volume of 15.6MB. The operator’s
rate for international roaming in Russia was RMB0.10 per KB, so the data fee for
international roaming was RMB 3,950.
As telecom networks and services grow rapidly, interconnectivity problems and
disputes similar to this are on the rise. Operators are in urgent need of capability to
monitor and control interconnectivity service at the network and service management
levels to prevent the recurrence of such events. As a neutral, fine-tuned assessment
system, the signaling monitoring platform has been widely recognized by operators. Its
applications in the field of interconnectivity, in particular, efficiently solve the complex
network compatibility issue among operators, improving the quality of
Complex interconnectivity
With an accelerating progress of globalization, exchanges and cooperation between
countries have become more frequent, catalyzing the rapid growth of international
telecom services in the mobile communications field and generating great profit for
mobile operators. In particular, major international events such as the Olympic Games
and the World Cup have made high-quality international roaming services a major
issue among mobile operators and an important magnet for them to attract high-end
customers. Meanwhile, operators are building or upgrading their networks, with more
new services going live at a faster rate, which is leading to a multitude of
interconnectivity problems among international operators, such as network
compatibility, connectivity, and settlement disputes.
Against this backdrop, the traditional way of operation and maintenance management
seems far from enough to address the complex scenarios. The industry now recognizes
the way of deploying signaling monitoring equipment at international gateway MSCs
(GMSCs) to monitor and control the quality of interconnected services by means of
signaling collection, decoding, and analysis and, therefore, enabling centralized,
automatic, precise, real-time, and efficient interconnectivity maintenance.
Currently, operators are enthusiastic about building their signaling monitoring systems,
and signaling monitoring applications go deeper with network evolution. With the
advent of the cloud computing era, sharing of massive signaling monitoring data will
surely open up new applications for operators and trigger a revolution in the mode of
operation and maintenance.
Interconnectivity among operators is roughly divided into inter-network services,
inter-network settlement, and international roaming. Signaling monitoring has
prospects of broad applications in all three fields.
Signaling monitoring for inter-network services
When an operator adds a new number segment, it requires operators that interconnect
with it to make corresponding configurations at the GMSC. Nonetheless, with
traditional ways of collecting service statistics, it is very difficult to make
configurations for a certain number segment. Therefore, it becomes a great challenge to
assure the quality of service (QoS) for new numbers, not to mention the delay in
information transfer among operators.
In principle, signaling monitoring works by merging collected signals into call detail
records (CDRs), analyzing and making statistics by different application scenarios.
With related call records in CDRs, the monitoring system can easily match a subscriber
number segment with corresponding CDRs and statistically work out key information
on the number segment, such as the call completion rate, response rate, and traffic
volume. Using comparison with other number segments in the same order of magnitude,
it is easy to identify the QoS of the new number segment and recognize problem areas
before notifying the peer operator to rectify. Likewise, as one of their competitive
measures, operators can place probability-based call restrictions against some number
segments of blacklisted operators, or in turn, identify such measures by competition to
protect their lawful rights and interests.
It is also true for operator’s transmission management, as the international transmission
line rent is high. Take an Indonesia-based operator for example. The rent per E1 is
above USD5,000 per month. Therefore, it is critical for operators to have an accurate
view of the use of transmission lines. Currently, the network management system can
only manage down to the level of trunk group, which is far from enough. For example,
certain faults such as inconsistent states of the Communications Intelligence Channels
(CICs) may cause several circuit timeslots to be unsuccessfully occupied. Yet, the fault
cannot be told from the statistical report on the trunk group and thus becomes hidden,
affecting the inter-network call completion rate and resource utilization rate.
In comparison, signaling monitoring can detect CIC in signals, providing an
interconnectivity report to operators at the level of CIC. It can identify CICs that have
never been successfully occupied and outgoing/incoming traffic distributions and
trends, to help operators identify and solve problems as early as possible.
Signaling monitoring for inter-network settlement
Existing inter-network settlement is mostly made by exchanging bills between billing
centers. Due to the great differences between international operators in terms of
network equipment, standards, and billing systems, it is very difficult to sort, check,
and verify bills. and disputes arise easily, posing tough challenges for inter-network
The best way of settlement is through GMSC signaling. GMSC signaling monitoring
can provide information such as response and clearing that are sent and received by
operators of both sides, and thus information like the number of incoming and outgoing
calls and durations can be derived as the basis for settlement. Such a way is more
efficient and accurate with unified standards.
Settlement standards for international traffic fees vary widely with countries, and
settlement fees are as high as over USD0.40 per minute in some countries. As traffic
volume of international calls to some countries is quite low, Chinese operators provide
subsidies as a stimulus. Since these countries usually have high settlement fees,
defrauders resort to frequent international calls to such countries via mobile IP cards for
illegal gains on high settlement fees. With traditional network management systems, it
is hard to recognize such deceitful acts. In contrast, signaling monitoring technologies
enable collecting statistics of a single subscriber’s behaviors and recognition of
suspected illegal actions such as excessively frequent, short, or long calls, providing an
accurate basis for operators to prevent fraud in network settlement.
Signaling monitoring for international roaming
With the rapid increase in international roaming services, many European operators see
nearly 20% of their revenues come from there. As most of the international roaming
subscribers are VIP customers, improving the quality of international roaming service
becomes a great concern to operators.
International roaming can be divided into outgoing international roaming and incoming
international roaming. When analyzing the process of voice services, SMS, and GPRS
network access for outgoing international roaming subscribers, it is known that the key
to ensure continued services for roaming subscribers is to keep smooth channels for
signal, voice, and GPRS data transfers between the subscribers’ home networks and
destination networks. Among them, signal transfer provides international roaming
service control, mobility management, and roaming SMS functions; voice transfer
provides international roaming connection control and voice service functions; GRX
networks provide data connection and roaming data functions. Signal transfer, voice
transfer, and GPRS data transfer among operators are generally realized by specialized
international transfer service providers.
International roaming comes with very complex service paths and involves a great
number of network elements (NEs). Its quality is related to numerous factors such as
the interconnectivity and compatibility between mobile networks, coverage of the
access networks, ownership of access services, and even the devices and SIM cards.
Any problem with any of those factors would affect international roaming
Take a Chinese operator for example. To enhance the management of international
roaming quality, the operator has organized testing teams to perform roaming field tests
outside China many times since the commercial launch of its 3G network in China. This
has helped solve a number of problems with international roaming on 3G networks
successfully. Nonetheless, this way of problem solving is very costly and cannot be
continued for a long time, nor generally adopted.
To monitor and control the QoS for international roaming subscribers, a feasible
approach is to deploy a monitoring system as part of the network management system
on the edge of the GRX network at international signal transfer points to collect
international signals. By analyzing signals for roaming subscribers, key information
like the registration success rate of a subscriber on the destination network as well as
voice, SMS, and data service accessibility, maintainability, and integrity can be derived
and user experience felt. Moreover, we may identify and handle problems with
international roaming in a proactive and timely manner through functions such as
real-time alerts and signal tracing, therefore improving the quality of international
roaming service.
With signaling monitoring, we can also acquire the distribution of roaming subscribers
by resolving international mobile subscriber identities (IMSIs) in international GMSC
signals. In this way, operators can get information on visitors to large-scale events
(such as the Olympics Games) and the distribution of outgoing subscribers’
destinations as precise marketing resources for service industries such as tourism and
aviation. Signaling monitoring is therefore able to bring operators value-added services,
representing an important exploration area for signaling monitoring in telecom
consulting and industry services.