Test the layer-3 Switch

In this comparison test, several products support layer-3 switching. In order to test its layer-3 performance, we use IXIA1600 and ScriptMate software to test throughput, latency, and other indicators, and test the layer-3 switching performance of several layer-3 switches under Static Routing.
In this section, we will first introduce the concept of layer-3 switching between tests. A layer-3 switch can be seen as a layer-2 switch with the layer-3 routing function. It is an organic combination of a router and a layer-2 switch.
The principle of layer-3 switching is to assume that two hosts A and B that use the IP protocol communicate through the layer-3 switch. When Site A starts sending, it compares its IP address with the IP address of Site B to determine whether Site B is in the same subnet as it. If the destination site B and the destination site A are in the same subnet, Layer 2 Forwarding is performed. If two sites are not in the same subnet, if Station A needs to communicate with Station B, station A must send an ARP (Address Resolution) packet to the "Default Gateway, the IP address of the "Default Gateway" is actually a layer-3 Switch module. When station A broadcasted an ARP request to the IP address of the "Default Gateway", if the layer-3 Switching Module knew the MAC address of Station B during the previous communication, then the MAC address of B is returned to the sending Site. Otherwise, the layer-3 Switch module broadcasts an ARP request to Site B based on the route information. Site B receives the ARP request and then replies to the layer-3 Switch module with its MAC address, the layer-3 Switching Module saves the address and sends it back to the sender Site A. It also sends the MAC address of Site B to the MAC address table of the layer-2 switching engine. After that, when A sends all the packets to B, the information can be exchanged at A high speed. Because layer-3 processing is only required in the routing process, most of the data is forwarded through layer-2 switch, so the speed of layer-3 switch is very fast, close to the speed of layer-2 switch, and the price is much lower than that of the same router.
Now let's take a look at how we perform a layer-3 test. Take the outstanding layer-3 Switch DGS3308TG of Digital China D-Link as an example. We connect the eight Gigabit ports of the vswitch with the eight Gigabit ports on the IXIA1600 tester. We configure the layer-3 Switch DGS3308TG, set the eight ports to eight different VLANs, and then set IP addresses for each VLAN. Then we configure the eight ports of IXIA, set their IP addresses to the IP subnet of the connected port, and then start testing.
The layer-3 switching test is similar to the layer-2 test on the project and network topology, throughput, partial mesh or full mesh full duplex throughput tests depend on different switches), latency tests, frame loss rate tests, and B to B tests.
Performance test result of layer-3 Gigabit backbone switch