IPv6 is defined by over 60 IETF RFCs. The implementation of very large and complex RFCs is prone to misunderstanding and misinterpretation. Conformance testing, with a comprehensive and rigorous test methodology, increases product quality and customer confidence. Conformance testing also saves time and money, by allowing vendors to verify a product抯 design throughout the entire product life cycle. Problems can be identified earlier in development, reducing costly last-minute rework and post-deployment problems.
Once the IPv6 network is up and running, the next major concern is how well it will perform. IPv6 introduces new control and data planes, along with transitional technologies like tunneling and dual-stack support. A precise understanding of performance inefficiencies and limitations is essential for networks planners and operators in designing their networks. NEMs are always under pressure to deliver more performance and scalability per dollar from their equipment. Both NEMs and network operators can benefit from a test methodology that can characterize data plane performance, including such metrics as:
and control plane performance such as: Size of forwarding information Routing scalability.
Initial IPv6 development will focus primarily on the software level, to prove functionality. As the technology matures enough to mainstream deployment, implementation will move down to the hardware level for the ultimate level of performance. The new IPv6 routing protocols ?like OSPFv3,RIPg, ISISv6 and MBGP+ ?will need to process larger addresses and routes to achieve scalability similar to that of existing IPv4 networks. NEMs, service providers, and network operators must properly characterize scalability in order to understand the impact of the new IPv6 design and to prevent bottlenecks. Tunneling will be a key technology to interconnect IPv6 islands during the early stage of IPv6 deployment. The scalability and performance of a tunneling mechanism depends on the number of tunnels a device can handle; this metric must be monitored and measured.
To characterize the performance bottlenecks of a new IPv6 design properly requires a test bed that can overrun the performance and scalability limitations of a device or system under test. Creating such a test bed from hundreds of routers or switches is prohibitively expensive and difficult to manage. NEMs and service providers need test tools that can simulate real-world network conditions affordably and manageably. To stress test both the control and data planes adequately, the test tool is required to emulate hundreds of routers and also generate wire-speed traffic.
IPv6 test tools must be able to perform a wide variety of functions to adequately test and validate IPv6 devices and systems. For conformance testing, the test solution must be able to fully exercise the control plane of the device or system under test. For performance and scalability testing, the test solution must be able emulate IPv6-capable routers at the control plane level and scale up for large capacity testing. The solution must also be able to drive wire-speed traffic through the system at the data plane level to fully stress the device being tested.
While simple router emulation can be run on PCs or workstations, an optimized test system is needed to provide complete testing capabilities and high levels of scalability. For example, to emulate a large network, a network interface on a test tool must support hundreds or even thousands of IP interfaces and MAC addresses ? requirements that standard off-the-shelf hardware cannot support. Purpose-built test hardware is required to provide the flexibility and scalability needed to test IPv6 systems adequately.
The IPv6 test tools must be able to emulate the full range of routing protocols used in today抯 IPv4 and transitional IPv6 networks, including OSPFv2, OSPFv3, ISIS, IS-ISv6,RIPRIPg, BGP and MBGP+. These routing protocols are used to advertise the underlying network topologies over which the IPv6 network is established.
IPv6 test tools must be able to fully stress the dual-stack data planes of dual stack routers in addition to IPv6-only scenarios. The test tool must:
Ixia has addressed the challenges of protocol conformance testing by developing IxANVL (Ixia Automated Network Validation Library), the industry standard conformance test suite. For protocol conformance testing, IxANVL supports over 30 protocols overall, and the IPv6 conformance test suite contains over 500 test cases to validate routers and hosts. IxANVL provides positive as well as negative test cases against the RFCs that specify these standards. Negative tests help validate device response to 搆iller packets.?
IxANVL performs its tests as a dialog: it sends packets to the router being tested, receives the packets sent in response, and then analyzes the response to determine the next action to take. This allows IxANVL to test complicated situations or reactions in a much more intelligent and flexible way than can be done by simple packet generation and capture devices.
IxANVL can run on standalone workstations or via Ixia抯 optimized test platforms. IxANVL can be completely automated using a scripting interface, and IxANVL source code is also available to users for customization, allowing a great degree of testing flexibility.
The general methodology employed by Ixia for testing the scalability and performance of IPv6 routers involves first surrounding the device or system under test (DUT/SUT) with Ixia hardware test interfaces. The Ixia system then emulates everything else needed to test the device, including other IPv6/IPv4 dual stack routers, IP route injection, IPv6 routing protocols, and traffic transmission. In this way, large and complex topologies can be simulated to test the DUT/SUT in realistic system environments, with a minimum of hardware requirements. For example, in Figure 12, four Ixia test interfaces are connected to the DUT with numerous routers being emulated per interface.
Ixia has developed two primary applications for IPv6 performance testing, IxExplorer and IxScriptMate, each with a distinct testing focus.
IxExplorer provides a high level of flexibility and functionality in protocol emulation, traffic generation, and analysis. IxExplorer is the primary controlling application for Ixia抯 purpose-built hardware test platform, allowing detailed configuration of protocols and analysis of test results.
Within IxExplorer, a comprehensive set of IPv6 routing protocols is supported, including OSPFv3, IS-ISv6,RIPg, and MBGP+ as well as multicast protocol MLD. IxExplorer controls the protocols?operation on Ixia抯 test hardware architecture, which supports a CPU running Linux on each test port. This dedicated emulation environment allows hundreds of dual-stack routers to be emulated on each network interface. Hundreds of thousands of routes can be advertised from each interface, and line rate traffic can be generated over the established connections. Alternatively, Ixia抯 IxChariot product can be used to transmit emulated enterprise application traffic over the IPv6 routers or network being tested to measure end-to-end application response times.
. Ixia router simulation.
IxScriptMate. IxScriptMate provides a framework for running automated test scenarios. Numerous test suites have been developed within the IxScriptMate environment for testing IPv6 and IPv4 traffic throughput performance, latency, tunneling and routing performance, and scalability. IxScriptMate simplifies the configuration process by defining a configuration for the test and displaying the relevant parameters for user input. Tests then run automatically, and the results are presented to the user.
Though the benefits of IPv6 are well understood, the cost of overhauling the existing IPv4 infrastructure is prohibitive for many network operators and service providers. The current attitude toward IPv6 in the US market could be characterized as 揑Pv4 is working. Why change??The real driving force for IPv6 will come from countries and regions whose only choice for global competitiveness in the next decade is to change to larger address space. The path to complete global IPv6 connectivity will be lengthy and full of challenges. Many transitional schemes and strategies will be used to ease the pains and minimize investment into IPv6 deployment.
The need for better test tools and methodology is essential for the success of IPv6. Both NEMs and network operators rely on test tools to identify design flaws and interoperability issues. Ixia抯 expertise in testing has been a large contributor to the success of the IPv4 Internet, and Ixia抯 comprehensive test tools provide the power and flexibility to manage the transition to IPv6.
