Spirent SmartBits System, Reference Manual

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Chapter 2: System Architecture
Traffic Generation and Performance Analysis
20 SmartBits System Reference
Traditional Cards and Traffic
The first series of SmartBits cards, called Traditional, generates one standard stream, or
one frame blueprint, plus one or two alternate streams per port, with the primary
processing located in the chassis controller.
For a summary of Traditional card features, please refer to Table 2-4 on page 22 .
Each stream may also generate thousands of continuously varied frames by incrementing
or decrementing source or destination addresses, or varying the frame content via VFDs
(
variable field definitions) in SmartWindow and SmartLib. These frame variations
exercise the DUT or system under test at up to full wire rate but do not have latency
measurements or out-of-sequence tracking for each frame.
Figure 2-6. Traditional Cards and Traffic
The Traditional architecture refers to the basic capabilities of all cards, including most or
all of the following features for the individual cards, available in SmartWindow and
SmartLib.
•
Generate Packets Up to and Beyond Wire Speed . Uses a variety of transmission
modes, with the ability to dynamically vary packet gap and length during
transmission, adjust preamble length, auto negotiate speed and duplex mode, and
capture frames.
•
Each Port Generates a Standard Stream . Also known as the Background template
or frame blueprint, the standard stream generated from a Traditional card is based on
one protocol (IP, UDP, or UDP) and capable of thousands of varied frames defined
through Variable Field Definitions (VFDs).
•
Variable Field Definitions (VFD) . You can use the three Variable Field Definitions
(VFDs) to customize a single stream per port in that each frame may be altered via
incrementing or decrementing data bits. For more details, refer to the glossary
definitions on
page 340 and to the online help in the applications.
•
Alternate Streams . In Traditional mode, there is an additional, simple Alternate
stream that can be defined, that is inserted in the traffic pattern at specified intervals
and can be used to simulate management frames. Gigabit Ethernet Cards have two
Alternate streams.