Powerful Hardware-Based Ethernet/iSCSI Analyzer for SAN and NAS
Typically, software-based analysis tools do not have access to dedicated capture RAM but rather must utilize limited resources on the host system to store captured data. Given the limited availability of system memory for use as a trace buffer, as well the impact using such memory has on network performance, not only can software-based data capture negatively affect the very network being monitored, the analyzer must be very selective in the data it captures to avoid exceeding available memory.
For these reasons, data is captured only from traffic that is either in-bound or outgoing – not both – from the monitored adapter, thus not providing valuable visibility into other communications occurring on the wire. Furthermore, timestamps for captured data generated or simulated by the capture engine often only have 10-20 microsecond resolution, and in many cases resolution is in milliseconds. For out-bound capture, timestamps are generated when the frame is generated, not when the actual transmission occurs on the wire. These discrepancies in timestamps can make it extremely difficult for network developers to correlate and trace specific transactions.