Telecom OSS/BSS: An Overview

1. Introduction

Before the initial 1970s, most of the support activities in a telephone

company such as taking orders, maintaining network inventory, provisioning

services (for example, line assignment and testing), configuring network

components, managing faults and collecting payments were performed

manually. It was realized that many of these activities could be replaced by

computers. In the next few years, a number of computer systems and

software applications were created to automate these activities. Examples

include TIRKS, RMAS, SES, etc. Thus came the term Operations Support

Systems (OSS).

OSS are “network systems” dealing with the communications network and

supporting processes such as maintaining network inventory, provisioning

services, configuring network components, managing faults.

Business Support Systems (BSS) is a newer term and typically refers to

“business systems” dealing with customers and support processes such as

taking orders, processing bills, collecting payments, sales and marketing,

supporting customer care agents in response to service requests, trouble

reporting and billing inquiries, etc.

OSS and BSS systems together are often abbreviated as BSS/OSS or B/OSS.

The term OSS was historically used to include both network and business

systems. Some industry analysts, system integrators and service providers

still use the term OSS to include both network and business systems, which

sometimes causes confusion.

This article provides an overview of some of the core areas in OSS and BSS

such as Order Fulfillment, Service Assurance and Billing systems. The

following BSS/OSS systems are covered:

Order Fulfillment – Order Management, Service Provisioning and

Inventory Management

Service Assurance - Fault & Trouble Management, Network

Performance Management, Topology & Configuration Management,

Planning & Testing

Billing - Billing Mediation, Rating, Billing Systems, Interconnection

Billing, Revenue Assurance

The article explains some of the basic functions of these systems. However,

this article doesn't intend to provide extensive details. For an extensive

overview of business activities, business process and functions, refer to

standards such as eTOM and TAM at http://www.tmforum.org/.

2. The Realm of OSS/BSS in Order Fulfillment, Assurance and Billing

2.1 Order Fulfillment

Communications products/services could range from Voice services to IP and

Data services to Hosting and CPE services. Some of the examples of

communications products/services are: 

Voice – Basic telephony, long distance, toll-free, Voice over IP (VoIP),

Contact Center, Local Access, etc.

Internet Protocol (IP) – Internet Access, VPN, Contact Center, VoIP,

Remote Access, etc.

Data – Layer 1 Wide Area Network (WAN) Services such as SONET,

Layer 2 WAN services such as ATM, Frame Relay, Private Lines, Layer 2

VPN and Metro Ethernet, etc.

Hosting – Custom Application Environments, Disaster Recovery,

Managed Services such as storage, security and network services, Web

Site Hosting, etc.

Order Fulfillment functions are a critical set of activities performed in order

to fulfill customer orders for services in a Communications Service Provider

(CSP) environment.

The following figure shows a very high-level view of activities performed in a

typical CSP environment.

After order entry, validation and submission, orders are decomposed and

sent for provisioning. Upon fulfilling the decomposed orders and appropriate

testing of the circuits, the orders are put into inventory. The following sub-

sections explain the Order Fulfillment related functions and OSS/BSS

systems.

2.1.1 Order Management

Order Management systems are complex systems that allow customer or

customer service representatives to capture and process new orders, modify

existing orders, process customer moves and changes, price quotes and

orders, validate orders, etc., while supporting multiple channels such as

Web, Order template documents and partner applications as well as multiple

lines of businesses.  

Order Management includes the following areas: 

Order Entry and validation – The Order Entry process captures

order details such as package or plan, service address, service details,

customer accounts, relevant contacts and applicable contracts. Data

entered during Order Entry is also validated against predetermined

rules.

Orders can be validated as the data is entered and/or validation after

all the data has been entered. Products/solutions that validate order

data as they are entered and walk the user through the product

configuration process are known as “Product Configurators”. One of

such tools available in the market is Selectica COnfigurator.

Order Decomposition – A single customer order can be decomposed

into one or more service requests, typically based on service types or

quantities, in order to be able to fulfill an order.

For example, if a customer order contains both a VoIP order and a

phone line order, two service requests would be created, one each for

VoIP and the phone line, each of which would be sent to the

appropriate provisioning systems.

One of the major problems service providers often grapple with is that, as

new services are added to the offerings, led by different business units, the

lack of flexible order management platform results in product/service specific

OSS/BSS applications. These in turn result in higher time-to-market as well as

increased costs of maintaining many different applications and systems.

Product catalog based Order Management solutions attempt to solve these

problems by storing and processing qualification rules for services based on

customer profiles, ordering channels, service locations, product

interdependencies, availability, customer eligibility and other business

constraints.

2.1.2 Service Provisioning

Service Provisioning systems are systems used to setup products/services for

the customer after an order for the services has been created and accepted

by the CSP.

Service provisioning activities include specifying the pieces of equipment

and parts of the network to fulfill the service, configuring the customer’s

routing path, allocation of bandwidth in the transport network, setting up of

wiring and transmission, etc.

Some of the systems that constitute provisioning systems are: Circuit Design

& Assignment Tools, Activation systems, and Field Service Management

systems.

Circuit design refers to specifying whether facilities exist to provide the

service and which pieces of the network equipment and routes the service

shall utilize.

One of the most widely used systems providing Circuit Design facility is

Telcordia TIRKS. Apart from Circuit Design support, it also provides circuit

order control, inventory record maintenance, selection and assignment of

components from inventory, and preparation and distribution of circuit work

orders. The order control module in TIRKS works with a circuit provisioning

system and operates in conjunction with other TIRKS components to assign

facility and equipment information for circuit orders and design circuits.

TIRKS can then provide automated design criteria for certain circuit orders.

The circuit design generated in TIRKS is then communicated to field

operations or automated activation systems for implementation.

Circuit Design and Assignment tools these days often have graphical tools

that allow a user to create services on a network map using mouse clicks

and drag-and-drop rather than drawing maps by hand or using an abstract

set of equipment identifiers displayed in a table.

After a service is designed based on the existing equipment and circuit

inventory, it is ready to be activated. If new equipment or lines need to be

configured manually, a Field Service Management (FSM) system is notified

which in turn dispatches technicians.

Moreover, certain activations can be performed automatically. For example,

issuing commands to ATM or circuit switches to provision circuits, to SONET

terminals to allocate bandwidth, and to a wide array of access devices such

as DSLAMS, Digital Loop Carriers (DLC), or cable modems. For such

activations, Service Activation systems pass the device specific commands

and configuration changes to the network elements, Element Management

Systems (EMS), Network Management Systems (NMS) or application hosts.

EMSs are designed to receive and execute commands sent by activation

systems on the devices. EMSs can also feed equipment status data back to

network and trouble management systems. EMSs use protocols such as

Common Management Information protocol (CMIP) or Transaction Language

(TL) or Simple Network Management Protocol (SNMP) to communicate with

activation and other systems.

Activation systems often comprise a library of adapters to various network

systems. They usually also support transaction control, i.e. the capability to

roll-back operations already performed, in case an error occurs.

It should be noted that Provisioning systems interact with the Inventory

systems, both to verify that the required network elements and other

facilities are available, and once the resources are provisioned - to reflect the

changed on-line configuration of the facilities. Therefore, provisioning

systems have close channels with inventory systems. As a result, some

vendors have combined workflow capabilities with inventory management

capabilities in their products.

 

2.3 Inventory Management

 

Tracking inventory involves tracking equipment, facilities and circuits.

Some examples of information tracked are: the location and quantities of the

equipment, how a piece of equipment is configured and its status, etc.

Inventory Management Systems track both the physical network assets

(such as equipment and devices) as well as “logical” inventory (such as

active ports, circuit ids, IP addresses, etc.), although not all support both.

By relating usage of network assets to specific customers and services, an

inventory system can help network operations determine the network usage

and available capacity as well as enable automated network design and

planning. Inventory Management Systems also enable Service Assurance

systems to find the impact of a network fault on the customer’s circuits.

Some tools also have “auto-discovery” features to automatically check

physical network assets and match the results with the information held in

the inventory. However, these work only with some of the newer intelligent

network elements.

2.2 Service Assurance

Communications service providers (CSP) strive to differentiate themselves

from their competitors by implementing attractive Service Level Agreements

(SLA). SLAs are formal contracts where the level of service delivered by the

CSP to his customer is stipulated. An SLA may specify levels of service

availability, performance, operation, etc. as well as penalties upon violation

of the SLA.

Offering SLAs implies that the service provider has the ability to monitor, act

and report the level of service, in order to assure the quality of services

delivered to the customers. Service Assurance refers to all the activities

performed for such an assurance. The goal of Service Assurance is to provide

an optimal customer experience, that helps retain existing customers, attract

new customers and prevent penalties arising out of violation of SLAs.

The following sub-sections introduce some of the common service Assurance

systems.

2.2.1 Fault and Trouble Management

Fault Management Systems are designed for detection, isolation and

correction of malfunctions in a communications network. They monitor and

process network alarms generated by network elements (routers, switches,

gateways, etc.). An alarm* is a persistent indication of a fault that is cleared

only when the triggering condition is resolved.

Examples of trouble or fault in a network are damage to an optical fiber line,

switch failure, etc. Such a problem in the network can result in a chain

reaction where many network elements in a certain path produce alarms*.

Fault Management Systems may be either a component within Network

Management Systems or as a standalone set of system and application

software.

The following figure illustrates how fault management works.

Network Elements are designed to provide various levels of self-diagnosis.

Older Network Elements might simply send an alarm notifying a problem

while newer Network Elements can provide more precise and detailed

messages. Fault Management Systems may collect alarms via SNMP traps,

CMIP events or proprietary agents, via EMS. They use complex filtering

systems to assign alarms to specific severity levels and correlate different

alarms to locate the source and cause of a problem.

After a problem is identified, the FMS then notifies appropriate network

operators as well as pass the problem information to a Trouble Management

System that in turn logs the problem and issues a trouble ticket to start the

repair process.

The Trouble Management System then sends commands to appropriate

systems such as Field Service Management to schedule and dispatch

technicians to repair the equipment and/or to EMS to reroute network traffic

around the problem areas.

Trouble Management systems also handle automatic escalation, such as

progression of a ticket from minor to major or major to critical, etc., and

support a variety of notification methods such as paging, emails, synthesis

voice dial-out.

Fault Management systems usually provide graphical network displays which

are projected on large screens at the Network Operations Centres (NOC).

NOC operators can see role-based views on their consoles, shortcuts to

operations they perform the most as well as tools to quickly make

connections to EMS to perform any testing or diagnostic operation.

2.2.2 Network Performance Management

Performance Management components in NMS and other Alarm Handlers

monitor applications and systems and collect performance variables of

interest at specified intervals. Performance variables of interest may be

service provider network edge availability, customer premises availability,

response times, packet delivery rate, packet losses, latencies, jitters and out

of sequence packet reorder, etc., to name a few.

One way to capture performance metrics is collecting event logs, CDRs and

other performance data such as counters or timers that the network and

system elements maintain as part of their normal operation. This is referred

to as passive measurement. Performance data is captured by polling MIB

using SNMP or using syslog, (I & II), FTP, EMS feeds, etc. Most passive

measurements report on a single network element.

For example, an Ethernet Switch may have a MIB which provides in and out

data volumes of each port, histograms of frame sizes, number and types of

erroneous frames, central processing unit (CPU) busy status. Associated

Remote Monitoring (RMON) MIB-type data can then list ten most active

users, etc. Performance Management tools can access the data by using

SNMP to poll the MIBs at predefined intervals.

Statistics on performance variables can also be captured via dedicated

network appliances known such as “probes” and “sniffers” that monitor or

probe customer’s local loop connections, packet performance, etc. This form

of performance testing is usually referred to as active testing.

Packet sniffers typically monitor signaling protocols such as SIP and RTP by

inspecting packets on the wire/fiber, using pings, DNS, FTP, HTTP fetches,

etc. Examples include WireShark and Geoprobes.

Probes such as Brix Networks BrixWorks Verifiers and Tektronix/Minacom IVR

tools typically emulate customer traffic in order to test or probe specific

paths to measure the quality of the services supported. Probes could be

either placed into the network or could be built into network elements such

as in the case of Cisco’s IP Service Level Agreements tools.

Note that active measurement measures a service, such as application

response time, instead of the internal operation of a network element.

An example of active network performance test is injecting “ping” (short,

network layer echo packet) into the network aimed at a remote IP address.

Round-trip time is measured if the ping packet returns, and an error counter

is incremented if it doesn’t.

Performance statistics captured by “active” or “passive” performance tests

are normalized and routed to relational databases and/or data-warehouses.

An alternative is to pass the performance data directly to Performance

Management tools. For example, Concord eHealth could collect performance

statistics from Netcool agents via SNMP polls at a pre-defined interval.

Performance statistics are initially analyzed to determine the normal

(baseline) levels. Appropriate thresholds are determined for each of the

interesting performance variable so that exceeding the thresholds indicates

a problem.

Performance Management tools then measure the performance variables

against SLAs defined as thresholds per application or service, on an on-going

basis. In case of exceptions they report them to alarm handlers. This form of

performance monitoring is reactive performance monitoring. Some tools also

support proactive monitoring by way of providing simulation tools that helps

network operators project how growth in network traffic will affect

performance metrics and plan to take proactive countermeasures such as

increase capacity.

Performance Management tools may also support real-time and historical

reporting. Some CSPs have taken performance statistics of the network

affecting customers’ circuits to their customer self-service portals.

2.2.3. Topology & Configuration Management

Older networks and systems were static and the network wiring was fixed in

place, and sometimes required long outages while changes to the network

and its configuration were being made. Any error or inconsistency in the

configuration files of different network devices caused problem, and

therefore these changes were well controlled [3].

According to [3], with the rise of IP-based, dynamically routed networks,

network topologies started becoming dynamic. The topology of the network

became dynamic because a few of routers might decide, on their own, to

shift routing patterns, or because a network operator group might add a new

router or switch to the network, possibly without everyone else in the

network operations center being aware of the changes. Instead of static

associations between users and network addresses (as was set in the old

“hosts” file), DHCP and other techniques allowed users to appear, move, and

disappear without providing prior notice to the network administration.

Most major NMSs therefore provide capabilities to automatically discover a

network’s actual topology, which is critical to understand network

performance or root cause of network alarms, etc.

Probes are placed into the network to automatically find devices and circuits.

Also, most network elements provide MIBs that can be polled via SNMP to

discover the network, although discovering the network topology in its

entirety may not be guaranteed. Backup paths, virtual private networks,

MPLS, etc., can make it very difficult to discover actual paths, through

multiplexed links, patch panels, and test equipment [3].

Also, most Topology Management Systems allow the network operator to

provide hints so that the system, for instance, in order that the system can

ignore certain portions of the network. This makes it easier to discover

relevant portions of the network more accurately.

Some service providers may run network discovery routines on a daily basis

to discover any unauthorized changes to the network topology as a result of

security intrusions or unplanned insertion of devices.

Moreover, network elements and computer systems have a variety of version

information associated with them. For example, a workstation may have:

Operation System, version 32, Ethernet Interface, version 5.4, TCP/IP

Software, version 2.0 and SNMP Software, version 3.1. Since multiple

engineers/network operators work on making changes to the network

equipment, tracking the changes manually would be very tedious and error-

prone. Configuration Management tools help automates the tracking of the

changes. Configuration Management systems store the configurations in a

database or LDAP server for easy access.

They also enable network operators to change configurations of the network

elements as well as to roll back a change to a previous configuration, if

required.

When a problem in the network occurs, network operators often search the

Configuration Management database for clues that can help solve the

problem.

2.2.4. Planning & Testing

Network Planning solutions help determine when a communication network

needs an upgrade or additional equipment as well as to predict the impact of

changes to a service provider’s network’s topology, configuration, traffic and

technology. They provide simulation tools that help the network operators to

project how growth in network traffic will affect the network performance.

Based on the results and other planning activities, network operators can

take countermeasures such as increase capacity.

Testing is an important activity in setting up a network or customer circuits.

For simplicity in understanding the gamut of testing activities, let us divide

them into the following:

1. Testing of existing network or a change

2. Integration testing of services configured for the customer

3. End-to-end testing of services configured for the customer

Testing the entire network platform - including the equipment, services and

call quality – is critical for assessing the system prior to deployment and for

service assurance in production environments [4].

Network testing tools usually simulate a production environment and

generate synthetic voice, video and data traffic, which helps measure

call/data quality, network performance, and the affects of any changes to the

network or increasing traffic or adding new applications. These tests typically

include tests like DNS, HTTP, RTP, Ping, etc. Also, during ongoing operations,

these testing tools enable active testing of facilities.

Another form of testing is integration testing of network setup for the

customer, i.e., routes, circuits, etc. configured for a customer. Network

operators or field engineers perform integration testing of services upon

completion of activations and other provisioning activities. Field engineers

typically use equipment and network element specific applications to

perform integration testing.

Upon completion of integration testing, field operations teams are notified to

perform end-to-end testing. End-to-end testing includes testing of circuits,

both within the CSP’s network as well as local access circuits between the

CSP and the customer premises. Some service provider’s use craft access

systems for the benefit of field technician’s access to their internal systems

through a hand held terminal [5]. The hand held terminal helps them to

access loop testing system and to view the complete test summary from

remote locations.

2.3 Billing

IDC [6] defines Billing as: the processing and compiling of charges and

enabling of revenue collection for network usage, feature transactions, and

access charges of the services.Mediation systems collect network usage data

from the network elements and convert to billable statistics.

The following figure depicts a simple Billing flow:

Traditionally, for phone calls, Call Detail Records (CDR) have been used to

record the details of the circuit-switched phone call. CDR includes

information on start time of call, end time of call, duration of call, originating

and termination numbers. CDRs are stored until a billing cycle runs. For IP

Based Services, a new standard is gaining acceptance called Internet

Protocol Detail Record (IPDR). IPDR supports both voice and data.

Billing systems use mediation output to determine charges for the

customers. It is also used to feed other downstream applications such as

Fraud and Churn Management.

2.3.2 Rating

Rating systems calculate the charge for an individual call, IP usage event,

etc. using the CDRs/IPDRs. Rating systems apply charges based on pre-

configured pricing rules, applicable discounts and rebates from promotions.

This rating process has grown increasingly complex in recent years. In older

times, it was solely a matter of taking the length of the call, assigning a price

based on the mileage band (calculated by cross-referencing the prefix of the

originating and terminating numbers in a table of values), and assigning

discounts based on the time of day (peak, evening, night), day of the week,

and holidays.

Modern rating systems can assign discounts based on calling circles, provide

flexible rating plans based on size of accounts and increase switching costs

[2]. These serve as strategic marketing tools but can be very complex to

administer and operate.

2.3.3 Billing Systems

Billing systems aggregate rated calls, IP/data usage events, etc. and

calculate customer invoices. In the United States, billing is usually performed

once a month.

Billing systems combine rated records with prior balance information,

payment records, recurring charges (such as line rentals), one-time fees

(such as installation and service charges), promotions and discounts

associated with the customer account, taxes and credits. Overnight billing

batch jobs are among the largest batch environment at a CSP’s operating

environment. Each customer is assigned a specific billing cycle.

According to Insight [2], the holy grails of the billing industry are unified

billing and convergent billing. With unified billing, a customer gets a single

bill for all services provided (or billed) by the service provider, appropriately

rated, discounted, and taxed, and a single contact for inquiries and

negotiation.

2.3.4. Interconnection Billing

In the competitive world of communications, service providers often tie-up

with partners, in order to bundle their own products with their partners. This

helps the service providers to provide attractive bundles of products and

services. However, in order to successfully settle interconnect billing

settlements an effective Interconnection Billing is required.

Interconnection Billing products support inter-working of a service provider’s

billing systems with the corresponding systems of another service provider,

based on interconnect agreements and contracts.

2.3.5. Revenue Assurance

Revenue Assurance & Fraud Management systems verify billing, detect and

identify unauthorized usage of service provider network assets. Some of the

kinds of frauds are Usage and Subscription.

Usage Fraud means that a customer uses the telecommunications network

illegally. This is accomplished either by obtaining a service with no intent to

pay or by obtaining unauthorized access to the network (i.e. “hacking” or

“cracking”).

Fraud Management systems typically detect and prevent unauthorized

access to a communications network by analyzing traffic patterns on the

network. Some examples are provided in [8]:

One technique involves analyzing the average call duration or the

number of calls placed to foreign countries to determine whether the

traffic patterns are consistent with a subscriber's call history or

pattern. If a call is inconsistent with the subscriber's call pattern

profile, the subscriber is provided with a report of the abnormal call

activity.

Other methods for dealing with the problem of unauthorized use

involve automatically denying or blocking access to the network when

abnormal use is detected to minimize the subscriber's financial loss.

Subscription fraud means that a customer obtains a service account by

giving a false identity (name and/or SSN) or by giving a false address or false

credit worthiness.

Detecting subscription fraud involves searching recent order and existing

customer data for multiple orders and/or accounts with the same customer

name, SSN, or service address.

Common subscription fraud patterns include:

Change of billing address within a few weeks of opening an account.

Substantial deviation of usage profile of a new user from an average

new user.

Common techniques to control subscription based fraud include threshold

based analysis, inference rules analysis, profile based analysis such as

habitual user profiles and neural networks.

Fraud Management Systems typically read and store usage data from the

service provider’s network switching equipment and allows queries to be

executed against the data that detect suspicious usage patterns.

They also allow operators to review customer accounts that have suspicious

activity, to track their investigation and record the final case resolution.

It should be noted that fraud is different from revenue leakage. Revenue

leakage is characterized by the loss of revenues resulting from operational or

technical loopholes where the resulting losses are sometimes recoverable

and generally detected through audits or similar procedures [1]. Fraud, on

the other hand, is characterized with theft by deception, typically

characterized by evidence of intent where the resulting losses are often not

recoverable and may be detected by analysis of calling patterns.

Another important class of Revenue Assurance tools includes Churn

Management tools. Churn management is an important area for service

providers that have subscription-based business - due to price wars,

aggressive marketing and promotions from competing service providers, and

customer’s expectations related to customer service.

Churn Management tools provide functions such as automated behavior

analysis, forecasting and simulation, empirical profiling, churn metrics

capture, that enable service providers to learn which customers are likely to

leave and take appropriate countermeasures.

3. Conclusion

3.1 Summary

OSS/BSS systems and applications automate many of the day to day

operations performed in a communications service provider’s operating

environment. They optimize the time taken to perform these operations and

make the business processes more efficient.

There are no all-encompassing OSS/BSS systems that can be installed,

integrated, tested and allow the service providers to easily modernize their

end-to-end operations functions.

Service providers, therefore, use all the different approaches: best-of-breed

in some areas, off-the-shelf in some, and home-grown custom applications in

the remaining areas, to modernize and optimize their operations.

More often than not, many of these OSS/BSS systems are integrated with the

others in a point-to-point fashion, as part of discrete projects and programs,

sponsored out of different business units. This leads to point-to-point

integration of OSS/BSS systems unless the programs/projects are planned

with a strategic goal.

A side effect of the difficulty in integrating the various OSS/BSS systems is

many of the OSS/BSS systems in a service provider’s operating environment

may not be integrated at all. For example, it is not unusual to find the

following scenario: when a customer orders a new telephone line, the

ordering system takes the details of a customer’s order, but a manual

process is present to configure the telephone exchange using a switch

management system. Details of the order entered in the Order Handling

system is re-keyed manually by the technician into the Switch Management

System – a process often referred to as “Swivel-Chair Integration”.

The article provided an overview of some of the core OSS/BSS areas in Order

Fulfillment, Service Assurance and Billing.