Internet Protocol version 6 (IPv6) Conformance and Performance Testing之四

IPv6 Testing - Sample Test Plans

The test plans presented here illustrate how Ixia's solutions address the challenges of IPv6 testing.

1. IPv6 Conformance Test
2. IPv6/IPv4 Forwarding Performance Test
3. Tunneling Functional Test
4. Tunneling Performance Test
5. IPv6 Routing Performance and Scalability Test

1. IPv6 Conformance Test

Objective: Verify the DUT's compliance with the following features defined in various RFCs:

• IPv6 (RFC 2460)
• Transmission of IPv6 Packets over Ethernet Networks (RFC 2464)
• IPv6 over PPP (RFC 2474)
• ICMPv6 (RFC 2463)
• Stateless Address Autoconfiguration (RFC 2462)
• Path MTU Discovery (RFC 1981)
• Neighbor Discovery Protocol (RFC 2461)
• Multicast Listener Discovery (RFC 2710)
• Tunneling (RFC 2529, RFC 2893, and RFC 3056)

Additional test suites are available for legacy IPv4 and IPv6 routing. Both IPv6 and IPv4 should be tested in a dual stack implementation.

Figure 1. IPv6 conformance test setup.

Test setup: An IxANVL Linux workstation connects directly to the DUT, or via Ixia test hardware, with one or two test interfaces (see Figure 1). The Ixia test platform will emulate either hosts or routers in IPv6 and IPv4 mode, depending on the configuration of each test case.

Methodology: IxANVL runs a number of test cases against the DUT based on the direct interpretation of various IPv6 RFCs.

1. Configure each IxANVL network interface with the appropriate network parameters, including those of the DUT, such as IP address, MAC address, gateway, etc.
2. Specify configuration of the DUT, typically via command scripts such as Expect scripts. IxANVL is able to automatically execute the scripts to configure the DUT before, during, or after the test.
3. Select a set of test cases to run in IxANVL (see Figure 2).
4. Run IxANVL in a batch mode with the command scripts, reconfiguring the DUT as required between test cases to match the IxANVL test setup.

Result: Number of tests passed/failed, including reasons for failed cases (see Figure 3).

Figure 2. IxANVL conformance test cases.

Figure 3. IxANVL test results.

2. IPv6/IPv4 Forwarding Performance Test

Objective: Characterize the performance of the data plane in forwarding IPv6 and IPv4 traffic. IETF RFC2544 defines how to characterize data plane performance. Ixia has implemented the RFC2544 test in IxScriptMate. Four tests have been developed to support RFC2544:

The back-to-back test determines how the DUT responds to different quantities of frames with the minimum gap allowed by the protocol specification.

• The frame loss test determines how the DUT responds to streams with different loading.
• The throughput test finds the highest rate at which the DUT can forward frames.
• The latency test reveals how much processing overhead the DUT requires to forward frames.

Figure 4. Packet forwarding performance test setup.

Test setup: A minimum of two Ixia ports will be used for this test, in conjunction with the IxScriptMate RFC2544 test (see Figure 4).

Methodology: This test will involve several test ports to match the DUT's port density. Ideally, the test should flood traffic to every input port of the DUT. A number of Ixia load modules will be connected to the DUT. Ixia's IxScriptMate is used to perform the RFC 2544 benchmark test.

1. Connect appropriate Ixia load modules with the DUT. Try to match the DUT's port density.
2. Run IxScriptMate on the client console. Select RFC2544 test.
3. Configure appropriate port and traffic parameters for each one of RFC2544 tests. Set the protocol type as IPv6 under Traffic Setup menu (see Figure 5).
4. Execute all four tests to characterize IPv6 performance.

Mixed traffic with IPv4: Testers can run another instance of IxScriptMate on the same console. The second IxScriptMate will run the same RFC2544 test with additional ports assigned to generate and measure IPv4 performance. Users can adjust the number of ports running IPv6 traffic (with the first instance of IxScriptMate), and the number of ports running IPv4 traffic (with the second instance of IxScriptMate). The goal is to generate a mixed IPv6 and IPv4 traffic to stress a dual-stack DUT.

Test Inputs:

• Packet length
• Offered load
• IPv6 and IPv4 mixed ratio

Results:

• Throughput
• Latency
• Packet loss

Figure 5. Configuring port and traffic parameters.

3. Tunneling Functional Test

Objective: Verify correct encapsulation and decapsulation between IPv6 and IPv4.

Figure 6. Tunneling functional test.

Test setup: Two Ixia ports will be connected to the DUT for this test - one to generate IPv6 traffic and a second one to monitor IPv6 over IPv4 tunnels (see Figure 6). The IxExplorer application will be used to generate and analyze IP packets. Various tunneling schemes will be exercised.

Methodology:

1. Configure the DUT to support the tunneling scheme under test.
2. Set up one Ixia port to generate IPv6 traffic with the properly configured IPv6 addresses to match the tunneling schemes supported by the DUT.
3. Set up the IPv6 traffic stream to include the proper data integrity signature.
4. Set up the receiving port to measure the tunnel traffic. Set up a capture buffer to analyze tunneled packets.

Test Inputs:

• Offered load
• Packet length
• Packet headers and payload
• Address range

Results: (Figure 7)

• Header and payload integrity check
• Packet loss
• Address translation - verify the IPv4 addresses

Figure 7. Tunneling functional test results.

4. Tunneling Performance Test

Objectives: Characterize the DUT's performance in encapsulating and decapsulating IPv6 tunneled traffic. IxScriptMate supports three tests for tunneling performance:

• The Tunnel Capacity Test finds how many frames the DUT loses with various numbers of tunnels.
• The Tunnel Frame Loss Test finds how many frames the DUT loses at various frame rates.
• The Tunnel Throughput Test searches for the maximum rate at which the DUT receives and forwards frames with no frame loss.

Figure 8. Tunneling performance test setup.

Test setup: A minimum of two Ixia ports will be used in this test, in conjunction with the IxScriptMate IPv6 Tunneling Test. It uses IPv6 tunnels with pairs of ports with one-to-one traffic mapping; one port transmits to one receive port. Users can specify multiple pairs of test ports to increase the loading. The transmit ports generate IPv6 packets and the receive ports expect IPv6 over IPv4 tunnel traffic. See Figure 8.

Methodology:

1. Configure the DUT to support the tunneling scheme under test. IxScriptMate currently supports manually configured tunnels, IPv4-Compatible tunnels, 6to4 tunnels, and ISATAP tunnels.
2. Set up the appropriate test parameters under IxScriptMate.
3. Repeat steps 1 and 2 for different tunneling schemes supported by the DUT.
4. Execute all three tests to characterize performance.

Test Inputs: (see Figure 9)

• Tunnel end points - IPv6 and IPv4 addresses
• Tunneling methods - Manually configured, IPv4-compatible, 6to4, and ISATAP
• The number of tunnels (required for tunnel capacity test)
• Maximum transmit rate
• Loss tolerance
• Frame sizes

Results: (see Figure 10)

• Frame loss
• Tunnel throughput
• Latency
• Packet integrity error
• Packet sequence error

Figure 9. Tunneling performance test parameters.

Figure 10. Tunneling performance test results.

5. IPv6 Routing Performance and Scalability Test

Objectives: Characterize the performance and the scalability of the IPv6 control plane. The IPv6 routing protocols, such as BGP4+, will be tested and characterized. The Ixia test tool emulates many peers/adjacencies and routes behind each test port; therefore, many complicated test scenarios can be done with only a few test ports. The typical tests in this category are:

• Forwarding Information Base
• Routing Scalability
• Route Convergence
• Routing Stability

Figure 11. Routing performance and scalability test.

Test setup: IxExplorer will be used to emulate multiple BGP peers and routes behind each physical port. A minimum of two Ixia test ports will be connected to the DUT for this test. Users can add more Ixia ports to match the DUT's capacity. See Figure 11.

Methodology:

1. Configure a number of IPv6 addresses that will be emulated by an Ixia port under the Protocol Interfaces folder.
2. Configure a number of BGP peers under the BGP protocol folder. The user can easily increase the number of peers in a spreadsheet setting.
3. Configure a number of routes for each BGP peer (Figure 12). Again, the user has complete control over how the routes will be set up, including the mandatory and optional BGP attributes for each route.
4. Start up the BGP emulation and observe all the routes that are registered and propagated by the DUT.
5. Set up automatic traffic streams to target all the advertised routes. Verify that the DUT can deliver traffic to the proper destination based on the emulated topologies.
6. Flap the emulated routes to simulate Internet instability (Figure 13).
7. Repeat the test procedure for OSPFv3, IS-ISv6 and RIPng.

Test Inputs: The size of the emulated topology can be adjusted to meet different test scenarios by varying:

• The number of emulated routers.
• The number of peers/adjacencies.
• The number of routes or LSA/LSP.
• The routes or links attributes.
• The duration and frequency of routes flapping.

Results: The key measurement goal is to determine the DUT's capability to forward traffic correctly under heavy loading and with dynamic fluctuation in the control plane. Typical measurements are:

• Packet loss
• Packet sequence error
• Misdirected packets

Figure 12. Ixia emulates multiple BGP peers with advertised routes.

Figure 13. Emulated routes can be flapped to simulate Internet instability.

Glossary

Care-Of-Address (COA)

A temporary IP address for a mobile device, the COA enables message delivery when the device is connecting from outside its home network. The care-of address identifies the device抯 current point of attachment to the Internet and makes it possible to connect from a different location without changing the device's permanent IP address: messages sent to the known permanent address are rerouted to the care-of address while the recipient can be reached there.

Classless Inter-Domain Routing (CIDR)
CIDR allocates and specifies the Internet addresses used in inter-domain routing more flexibly than was possible with the original system of IPv4 address classes. As a result, the number of available Internet addresses has been greatly increased.

Correspondent Node
A peer node with which a mobile node is communicating. The correspondent node may be either mobile or stationary.

Dynamic Host Configuration Protocol (DHCP)
A communications protocol. DHCP automates the assignment of IP addresses in an organization's network. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is plugged into a different place in the network.

Exterior Gateway Protocol (EGP)
A protocol that distributes routing information to the routers that connect networks.

Foreign Agent (FA)
(In Mobile IP,) a router serving as a mobility agent for a mobile node. A foreign agent works in conjunction with another type of mobility agent known as a home agent to support Internet traffic forwarding for a device connecting to the Internet from outside its home network.

Generic Routing Encapsulation (GRE)
A protocol that allows one network protocol to be transmitted over another network protocol, by encapsulating the packets to be transmitted within GRE packets.

Intermediate System to Intermediate System (IS-ISv6)
An OSI/IP routing protocol, IS-ISv6 is the new version that supports IPv6 addressing. MPLS traffic engineering parameters can be distributed with IS-IS using extensions to the protocol (IS-IS-TE).

Internet Control Message Protocol v6 (ICMPv6)
An extension to IP that allows for the generation of error messages, test packets, and informational messages related to IP.

Internet Gateway Protocol (IGP)
Protocol that distributes routing information to the routers within a network. The term 揼ateway?is historical; 搑outer?is currently the preferred term. Example IGPs are OSPF, IS-IS and RIP.

Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)
An IPv6 transition mechanism, ISATAP allows IPv6-in- IPv4 tunnels to be created automatically within a site. To obtain address and routing information, each host queries an ISATAP router within the site.

Maximum Transfer Unit (MTU)
The largest size packet or frame that can be sent in a packet- or frame-based network such as the Internet. If the MTU size is too large, the packet may encounter a router that can't handle the packet, resulting in retransmission. Too small an MTU size means relatively more header overhead and more acknowledgements that have to be sent and handled.

Mobile Node
A node that can change its point of attachment from one link to another, while still being reachable via its home address.

Multi-Protocol Border Gateway Protocol Plus (MBGP+)
MBGP+ enhances BGP to support more types of advertised routes, including IPv6 routes.

Network Address Translation (NAT)
The translation of an Internet Protocol address used within one network to a different IP address known within another network. This allows duplicate IP addresses to be used within an organization and unique addresses outside.

Open Shortest Path First (OSPF)v3
A link-state routing protocol used by IP routers located within a single Autonomous System (AS) to determine routing paths. OSPFv3 is the version supports IPv6 addresses.

Routing Information Protocol next generation (RIPng)
An Internet routing protocol that uses hop count as a routing metric. RIP is the most common IGP used in the Internet. RIPng is the new version that supports IPv6 addresses.

Acknowledgements

Authors: Dean Lee, Elliott Stewart