IPv6 Router Performance Evaluation Checklist

For the time being, the IPv6 networks are small compared with IPv4, and the IPv6 traffic most likely represents a fraction of the existent IPv4 traffic. For these reasons, operators would tend to look at IPv6 performance in terms of its impact on the revenue-generating IPv4 services. As focus moves toward large-scale deployments, router IPv6 performance becomes an important factor in network planning and design.

This chapter underlines the relevant aspects of router performance while showing the importance of keeping in balance all the other factors relevant in router selection, such as feature richness and cost. It also discusses the impact of IPv6 protocol specificities on router performance. The chapter provides guidelines on practical and objective evaluation methodologies of router IPv6 performance. From a practical perspective, this information can be summarized in a checklist of major items to be verified when evaluating a router's IPv6 performance. Table 11-8 shows this list.

Table 11-8. IPv6 Router Performance Evaluation Checklist

Test Scope	Test Targets
Control plane	Evaluate the CPU impact of targeted IPv6 features. For routers that will operate in dual-stack mode, add the result to the operational CPU values (generated by IPv4) to see whether it will lead to comfortable overall CPUs (typically below 60 percent under regular traffic loads).
	Evaluate the memory needs for the IPv6 routing tables. For routers that will operate in dual-stack mode, add to IPv4 memory use to see whether it leads to comfortable overall memory use.
Data plane	Measure unicast interface-to-interface and system-level throughput performance for basic IPv6 traffic and no advanced router features enabled. Pay particular attention to the throughput results above the IMIX average packet sizes.
	Measure unicast interface-to-interface and system-level throughput performance for IPv6 traffic with various extension headers and no advanced router features enabled. Pay particular attention to the throughput results above the IMIX average packet sizes.
	Measure unicast interface-to-interface and system-level throughput performance for basic IPv6 traffic with advanced router features (the features targeted for the deployment such as ACLs, QoS, and so on) enabled. Pay particular attention to the throughput results above the IMIX average packet sizes.
	Evaluate the CPU impact of forwarding the expected IPv6 traffic rates. Both central and linecard (where applicable based on the router design) CPU should be measured.
	Measure IPv6 multicast performance in terms of both forwarding rates and replication.

This chapter is also making the point that today's routers and layer 3 switches are ready to support large-scale, high-performance IPv6 networks. They deliver line-rate forwarding of IPv6 traffic in the range of packet sizes relevant for most applications. The data presented supports this statement in the case of platforms of various designs that address the entire market spectrum. IPv6 router performance meets the high standards set by IPv4.