Quality assurance for Flughafen Düsseldorf GmbH following the migration of their data network

Our customer
The Flughafen Düsseldorf GmbH is the service company of the Düsseldorf International Airport (http://www.duesseldorf-international.de). In addition to the operation of the airport and the provision of associated services, the company is also responsible for the entire information and communications infrastructure at the airport.

Project aims
The project aim was quality assurance in regard to the migration of the data network of Düsseldorf Airport to a more advanced and modern network. The following performance package was agreed upon with the customer:

• Production of a detailed test plan to cover all test scenarios
• Measurements of the performance and durability of selected network components at the various protocol levels
• Measurements at typical points in order to facilitate the evaluation of the performance of the overall network
• Support for the process of network swapping with protocol analysers
• Presentation and evaluation of the results in a full and comprehensive test report

Description of the unique network
The backbone of the network that was tested was comprised of a number of ATM switches that were connected to very broad band interfaces. The access region consisted of components that were in turn connected to the backbone via ATM interfaces with narrow band widths and Fast Ethernet Modules.

The test scenario and the EANTC mission
During the various measurements, the following test scenarios were considered:

• ATM Quality of Service measurements
  The quality of service measurements tested whether the full backbone bandwidth was available for the service categories CBR, VBR, UBR at the ATM layer. They determined the latency and inter-arrival times of the ATM interfaces in the backbone at the ATM-cell layer.
• Validation of the Ethernet interfaces and the LAN Emulation services (Layer 2).
  In the first instance, all Ethernet Ports of the systems under investigation were subjected to a broadband test to determine proper functionality. The second step was an Ethernet - ATM - Ethernet test (attaching various VLANs/ELANs in accordance with 802.1q, measurement of the Durchsatz and the latency times).
• Performance measurement at the TCP/IP level (Layer 3)
  For the performance measurements at the TCP/IP level, real IP flows were emulated in the way they would be expected to be later in the backbone of the airport network. Several parallel IP flows were applied in the same IP sub-network (test of IP forwarding performance) and in different IP sub-networks (test of routing performance).
• Signalling Performance (point-to-point and point-to-multipoint)
  Performance tests of the ATM-signalling were carried out under normal operation (full operation of all components) and for a simulated partial failure. The switching of existing connections were investigated, as were the influence of the redundancy switching on the connection times.
• Outline of the network
  Stability and redundancy tests of the LAN emulation service and the ATM backbone. The tests of the LAN emulation signalling check whether the LAN emulation operates properly in the event of an LEC failover (this is the redirection of an LAN emulation client to the redundant LAN emulation server).
• Support with commissioning / Network switching
  The analysis with ATM and Ethernet measuring equipment and protocol sniffers were used on site to identify configuration problems rapidly.