Netflow Mediation

Golden Telecom, Inc. listed on NASDAQ under the symbol 'GLDN' is the largest independent facilities-based provider of integrated telecommunications and internet services to businesses and other high-usage customers and telecommunications operators in major population centers throughout Russia and other countries of the Commonwealth of Independent States (CIS).

Project: Netflow Mediation

Technologies:

• Sun Java/J2EE
• Oracle AS 9.x
• Netflow
• Cisco IOS
• TCP
• UDP
• SNMP

Azoft company has long-term partnership with one of the leading telecom and internet Russian providers, Golden Telecom. Azoft maintains some software developed inside Golden Telecom and carried out several projects on development of new or porting and extending the capabilities of existing software. One of such projects was development of NetFlow Mediation, a system for detailed traffic collection used for billing clients.

The system backbone consists of routers, collectors, and central server. Routers either send detailed information on traffic to collectors using Netflow protocol or publish it so that it can be retrieved with SNMP protocol. Both protocols use UDP as transport layer protocol. Collectors filter out this information and send it over TCP/IP to central server, where it is stored in tables that reflect the characteristics of protocols it was retrieved with. To use this information for billing purposes, it needs to be further processed and stored in suitable format in a relational database.

The original system, developed within Golden Telecom, relied on Netflow version 5 protocol for collecting data from routers. Open-source programs cflowd and cfdcollect ( http://www.caida.org), written in C, were used as collector and at the server to store data in ARTS format, respectively. There was a developed in-house Java-processor that parsed ARTS files (ARTS-parsing components were ported from open-source C library arts++) and compiled the information ordered by time (per hour) and IP-address into an Oracle database. Azoft improved this system by modifying cflowd, cfdcollect and Java-processor to allow for retaining information on Type of Service byte in IP protocol, that is used in Quality of Service concept – differentiating in bandwidth and reliability for different clients with different sort of traffic (IP-TV or streaming media versus static pages), and on original IP-address instead of subnet.

Azoft also developed processors for 2 other types of raw traffic information coming to the server – one originating from Netflow version 9 protocol and another – produced by Cisco IP Accounting utility that relies on IOS operating system and SNMP protocol. Actually, there is one more processor called IP VPN that derives from Netflow 5 processor. It takes account of the VPN traffic, finding the router ports that are connected into VPN with the help of special SNMP-based utility.

Modification of collector and processor for Netflow 5 protocol allowed Golden Telecom to implement more flexible billing schemes for clients and to generate more detailed reports for them. Development of the other processors was urged, on the one hand, by introduction of new hardware supporting Netflow version 9, and on the other hand, by the need to further improve accounting and billing.

The “NetFlow Mediation” project proved the ability of Azoft team to work with complex systems developed outside and to modify them, building on existing foundations. Azoft successfully extended the existing spatially dispersed and heterogeneous system, that uses a large number of physical devices (routers and collectors), various protocols and software, and produces huge amount of data (up to several gigabytes a day), without even having access to the real system – working only with models and emulators. When working on the project, Azoft had to cope with such non-trivial tasks, as restoring corrupted during the famous blackout in Moscow in summer 2005 ARTS files with traffic information. At present, Azoft has long-term contract with Golden Telecom for support and maintenance of Netflow Mediation system.