In 2016, global IP traffic equaled 1.2 ZB per year; by 2021, it will reach 3.3 ZB per year – almost triple the traffic within just a few years’ time. That’s a massive leap in volume, necessitating high-speed networks. Telecom networks won’t be able to maintain service level and capacity without deploying 100G network links. To do so effectively, they also need to test and troubleshoot these links.
A powerful analysis tool
When deploying new solutions, quality and maturity are critical since there are so many services and subscribers depending on stable data networks today. Testing new network solutions or new versions of networking products or applications is a challenge because synthetic test cases do not disclose all potential issues. Replaying real production network traffic provides more realistic test scenarios. Moreover, the test coverage can be extended by replaying traffic from many different networks.
When the inevitable network issue arises, efficient troubleshooting reduces the interruptions and possible downtime of services. Network traffic replay provides a powerful tool for reproducing and analyzing issues in a lab environment, not affecting the production network. Identification of network issues requires precise replay, throughput-wise and timing-wise. For example, traffic micro-burst can only be recreated in a lab environment if the solution supports full throughput and precise timing of packets replayed.
Choices in network traffic replay
The market offers packaged capture and replay solutions for 100G network traffic. In some cases, these products match the actual need, but in other cases, the solutions are way too expensive, have too many features or cannot be customized to special use cases.
That’s one choice. The other choice is to build your replay solution. You can do this with a COTS server, a standard Linux OS and a 100G smart NIC. The COTS server has all the horsepower and I/O performance needed to run 100G replay. Linux OS enables use of open source software or easy application development and feature customization. The smart NIC ensures full throughput transmit for any packet size, with precise transmit timing, with some smart NICs having one-nanosecond time resolution.
The building blocks of a 100G replay solution
For maximum efficacy, the building blocks of a high-performing 100G replay solution require certain qualities.
For the highest replay performance, a best practice is to have maximum memory bandwidth available on the server. The server should be populated with the maximum number of DDR4 memory blocks to allow full use of all the memory channels. Another recommendation is to use dual rank DDR4 or memory blocks running at least 2133 MHz or higher. To replay large files, the packet store output performance limits the maximum average replay speed. Fast Solid State Disks should be considered for high-speed replay.
Another best practice is for the smart NIC to support a 100G network interface with line-rate capture and transmit for any packet size, high-precision time stamping of received traffic, high-precision transmit timing, an efficient buffer system and an optimized DMA scheme over the PCIe interface.
Capture and replay applications based on open source are available, and some smart NIC vendors include tools for capture and replay in their software suite. The application should use server memory for buffering traffic from packet store before transmission. This is to compensate for the difference between 100G peak network packet rate and maximum read rate from the packet store.
The choice is yours
With the current astronomical levels of network traffic and a projected tripling in volume, high-speed networks are no longer a nice-to-have but a must-have. Networks performing at this speed need 100G links, which require testing and troubleshooting. The beauty of network traffic replay is that it enables testing outside the production network so that real-time performance is not hindered. Complete capture and replay solutions are available on the market, but you may choose to build your solution to save money and deliver just what you and your customers need. Just be sure to follow the best practices above to ensure a high-performing final product.
