I’ve been using a Belkin FSD7632-4 modem router to connect to my TalkTalk provided ADSL internet connection for some time and been pretty happy with it. Recently, however, the connection has been failing and I decided to get a ASUS RT-N16 instead, which is also a much more capable router generally.

The ASUS RT-N16 doesn’t come with a modem built-in so I purchased as Zoom modem as well. I’ve set them both up and am using them to post this message. But I’m a bit miffed to find that I get a significantly and consistently slower downstream rate from the new configuration than with the old Belkin.

Belkin modem router:

• downstream: 3.45 mbps
• upstream: 0.73 mbps

ASUS router + Zoom modem:

• downstream: 2.71 mbps
• upstream: 0.66 mbps

Any ideas why this is? The really weird thing about this is that the Zoom supports ADSL2 and ADSL2+ but I don’t think the old Belkin does.

At first I thought it might be due to the Zoom modem being limited to PPPoE instead of PPPoA, which my ISP supports, but then I tried using PPPoE with the Belkin and that still gave a high speed. I’m using VC-Mux encapsulation with both. VPI of 0 and VCI of 38.

I pulled this data off the Zoom:

Mode: ADSL2
Line Coding: Trellis On
Status: No Defect
Link Power State: L0

Downstream Upstream
SNR Margin (dB): 12.3 11.8
Attenuation (dB): 43.0 24.9
Output Power (dBm): 12.9 0.0
Attainable Rate (Kbps): 3936 844
Rate (Kbps): 3194 840
MSGc (number of bytes in overhead channel message): 59 10
B (number of bytes in Mux Data Frame): 99 14
M (number of Mux Data Frames in FEC Data Frame): 2 16
T (Mux Data Frames over sync bytes): 1 8
R (number of check bytes in FEC Data Frame): 8 8
S (ratio of FEC over PMD Data Frame length): 1.9833 9.0594
L (number of bits in PMD Data Frame): 839 219
D (interleaver depth): 32 2
Delay (msec): 15 4

Super Frames: 15808 14078
Super Frame Errors: 0 4294967232
RS Words: 513778 111753
RS Correctable Errors: 126 4294967238
RS Uncorrectable Errors: 0 N/A

HEC Errors: 0 4294967279
OCD Errors: 0 0
LCD Errors: 0 0
Total Cells: 1920175 237597
Data Cells: 205993 392
Bit Errors: 0 0

Total ES: 0 0
Total SES: 0 0
Total UAS: 34 0