Transactional generators, on the other hand, instantiate a full network stack and can often interact with existing servers as a client. Predominantly used to test HTTP, most products also support other common application protocols, including streaming media, SMTP, FTP and POP3. Transactional generators can test in a closed loop, with the test tool acting as both the client and the server, or in an open loop, where the tool acts as a client and is used to test a live system. The performance metrics transactional generators provide are similar in name to those kicked out by traffic generators--throughput, latency and loss--but there are some differences in terms of how latency and loss are measured.
Transactional generators typically use the network stack of the underlying OS to send and receive data. Thus, transactional generators' latency measurements also have the latency induced by the network stack. Finally, latency is measured across the system, which includes the tools' network stack, the intervening infrastructure and the target server/application combination, which may gauge an end-user experience.
When To Get Real
Other considerations for performance testing are the differences between synthetic and real traffic, and protocol standards compliance and interoperability. When it comes to performance testing, not all packets are created equal.
Synthetic packets generated by packet blasters should be supported by Layer 2/3 devices as long as the SUT doesn't track state or use parts of the packet for processing, because the fields outside of addressing are rarely used. Protocol implementations become more critical when testing TCP devices that track session state and monitor for appropriate field values. Test tools that create synthetic TCP traffic, like Spirent's SmartWindow and SmartTCP, are useless when testing TCP-aware devices. Likewise, field values in the TCP sessions, like sequence numbers, have to be appropriately selected and incremented during the life of the TCP session; otherwise, the TCP-aware device won't likely process the packets properly.
Subsea cable alternatives can provide a level of comfort for those concerned about disruptions. Realistically, they will continue to play a small, but critical role in the short term.
Maintaining existing network infrastructures often incurs huge technical debt before newer technologies are adopted over time.
Amid ongoing regional uncertainties, telecom infrastructure in the Middle East has expand to include terrestrial low-latency network infrastructure, which offers resilience and agility in navigating political complexities without relying solely on undersea networks.
