A. Joseph Dupre III
Technical Product Manager


September 27, 2016 by A. Joseph Dupre III

0For many years, users have leveraged IxLoad’s powerful AppReplay to more easily recreate their test world at scale. The great news is that this application replay feature is now available on our IxLoad VE virtual platform!

AppReplay models both emerging and proprietary TCP and UDP applications by allowing users to import a capture file that contains an application flow of interest and playback a Stateful TCP and UDP replay instance of that flow to the live physical network.

Not only can AppReplay replay an imported flow, but also allows the user to scale-up the traffic flow parameters based on that one flow and create a high-scale, repeatable test from one simple import of a representative transaction flow. Several dimensions familiar to long-time IxLoad users are available to adjust scalability including Initiator Peer Count, Connections/Second, Concurrent Connections, Transactions/Second, and Throughput.

A sub-feature within AppReplay called Stateless IP Replay maintains timing and packet boundaries appearing in the import capture file and allows this timing to be replayed to the physical network with the same synchronicity as the source material. If a user wants to be able to play with the time dimension characteristics of the application flows after import, they can compress or expand the inter-packet time during replay using a multiplication factor available in the GUI. This powerful component of AppReplay is particularly useful for test scenarios involving DPI (deep packet inspection) analysis and other timing-sensitive heuristic models.

The AppReplay activity-per-flow measurements include a wide array of per-flow statistics including Tx and Rx bytes, TCP connection latency distribution, and per-IP, per-VLAN, and per-User metrics.


Figure 1. Custom TCP flow activity replay configuration options window

With the advent of AppReplay on IxLoad VE, users of the IxLoad virtual platform can now leverage the power of modeling a new class of emerging and proprietary application flows within the SDDC (software-defined data center). Many of the command and control application flows associated with SDN (software-defined networking) and NFV (network functions virtualization) can be proprietary or in some way customized and enhanced for individual organization needs, with additional transaction messages, optional headers, and the like.

The proprietary or modified standards protocols often need to be tested for scale long before standards bodies have unified the industry practices or less than a handful of emerging application flows become the defacto standard. Networking infrastructure needs to be tested to verify it will be capable of handling the application traffic load in production for these evolving applications. This is particularly true in the software development and virtualization spaces, where the shift towards CICD (continuous integration continuous deployment) is driving down the test cycle times between development test and full production deployment.

When IxLoad VE is used to replay emerging and proprietary applications via AppReplay activities in a virtualized environment, the test engineer is able to scale up to production far more easily than if they had to configure and spin-up multiple virtual machines and application instances in order to see how the new application behaves at scale. IxLoad VE users who are already benefitting from the same type of economy of scale can enhance their testing with additional application flows not already within the vast array of application flows pre-defined in IxLoad.


Figure 2. Custom UDP flow activity replay configuration options window

From a test perspective, the intersection of wireless technologies with virtualization technology in recent years has blossomed with opportunities for verification and system-level testing where the technologies can evolve and explode even faster than testing standards can be defined to categorize and quantify performance. AppReplay on IxLoad VE flexibly meets the critical need of providing application flow scalability to vEPC (virtual evolved packet core) and other continuously enhanced and extended IP-based application delivery infrastructure systems.

AppReplay support on IxLoad VE is now available with the IxLoad 8.10 EA Update1 release. The AppReplay feature is available to all licensing tier levels for an IxLoad VE subscription.