Routing Performance

I put the 628 through our suite of router tests, with the results shown in Table 1 along with the DGL-4500 for comparison.

Table 1: Routing throughput

The 628 is slower than the 4500 due both to its less powerful CPU but also its 10/100 Mbps Ethernet vs. the 4500's gigabit. But its throughput is plenty speedy for any Internet service that it will be connected to.

Figure 6 shows a composite of WAN to LAN, LAN to WAN and simultaneous up/down IxChariot throughput tests. Note that I disabled the QoS Engine and SPI to run the router tests.

You can see unidirectional throughput of almost 90 Mbps in each direction. But bi-directional testing left me scratching my head. My first simultaneous up and downlink test showed throughput shared evenly in each direction. But when I started to run the maximum simultaneous connection test, I wasn't getting very high numbers.

Figure 6: DIR-628 routing throughput

So I reran the bidirectional tests and found the mismatch between up and downlink throughput shown in the lower traces in Figure 6. I ran and reran the tests using different computers, power cycling the router and even changing switch ports. I even ran a throughput check directly between the two computers used in the tests, plugging both into the 628's switch, and found nice even throughput sharing between receive and transmit. But, try as I might, I could not reproduce the initial results.

But, as I did when testing the Linksys WRT54G2, I tried reducing the IxChariot send rate from its UNLIMITED default to 40 Mbps and found it restored the even throughput sharing. So it looks like there may be something wonky with buffer management somewhere.

The erratic throughput that resulted from running heavy traffic loads in both directions was reflected in the relatively poor maximum simultaneous connection showing of only 32 connections. I suspect if the bidirectional throughput issue were fixed that this test result would also improve.

Use the Router Charts to see how the 628 stacks up against other routers.