Specifications

CHAPTER 2. NETWORK PERFORMANCE MEASUREMENTS SYSTEMS 5
Figure 2.1: The IXIA IxCore Network Tester
system, BrixWorx. The Brix 2500 Verifier calculates fundamental network performance
statistics (such as one-way packet latency, jitter and packet loss) and application respon-
siveness (such as Web page download and call setup time) by measuring high-level ap-
plication transactions. Timing measurements use the Brix 2500 Verifier’s hardware time
stamp engine and a GPS module, which can provide worldwide, accurate synchronization
to sub-100 microsecond precision, allowing Gigabit speed measurements.
2.1.3 Spirent Adtech AX/4000
The AX/4000 is a system for testing IP Performance and Quality of Service. AX/4000
Test Modules generate and analyze Layer 3 IP traffic at speeds up to 10 Gbps, while
software options enable sophisticated proto col emulation and decoding, control and data
plane testing, routing and MPLS emulation, and more. The real-time traffic generation
supports multiple traffic sources, traffic distribution models, packet length distributions,
class of service traffic prioritization and error injection in the data streams. The system
offers traffic filters, histograms and charts and protoc ol decoding. AX/4000 is a modular
multi-port system capable of testing multiple transmission technologies such as ATM, IP,
Frame Relay and Ethernet simultaneously at speeds up to 10 Gbps. It is built with FPGAs
and it offers a C/TCL function library for writing scripts. It also supports GPS timing
with an accuracy of 1us for one-way latency measurements.
2.1.4 Surveyor and RIPE
Surveyor and RIPE are systems that make one-way delay measurements over the Internet
and require a Global Positioning System (GPS) to provide clock synchronization between
sites. Both of these tools make end-to-end active performance measurements of the Internet.
They rely on a dedicated PC running Unix to b e placed at each monitoring site. Each PC
in turn relies on a Global Positioning System (GPS) device to obtain accurate time and
to synchronize time between each of the monitors. The monitors send packets at Poisson
randomized time intervals to each other and use these packets to gather one way end-to-
end delay and loss measurements. They also make concurrent traceroutes which provide
route history information. Each box (monitoring agent) has its own GPS receiver so the