Do I need a new modem or router or what?

One of the reasons I am not convinced I need a new modem is because our internet speed has recently deteriorated, but here goes.

Please don't laugh if I ask something absurd :??:

I have a Linksys BEFCMU10 ver. 4 modem with a D-Link DIR-655 router. I just found out today that my modem has a DOCSIS ver 1.1 even though I upgraded the modem from ver. 2 to ver.4. According to the Linksys support forums ver. 2 hardware cannot be upgraded to DOCSIS ver 2.0 unless Comcast does something on their end.

Anyway, here is my data from ShaperProbe:

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server

Estimating capacity:
Upstream: 1238 Kbps.
Downstream: 26085 Kbps.

The measurement will take upto 3.0 minutes. Please wait.

Checking for traffic shapers:

Upstream: No shaper detected.
Median received rate: 1269 Kbps.

Downstream: Burst size: 9356-9924 KB;
Shaping rate: 15941 Kbps.

I have Performance tier service but am not receiving the speeds expected. My son especially complains about his online gaming which for the past several days has been dropping out several times a night. Even when I am just surfing the web the page loads take longer than usual.

I am plugged in to the modem directly right now and have a Ping of 213 ms, Download of 16.04 Mbps and Upload of 1.73 Mbps. Last night on another computer that was connected via wi-fi my download was 0.064 Mbps and upload was 0.038 Mbps. Things are definitely faster this morning.

I have now changed the computer from a direct connection to the modem to an ethernet cable into the router. I reran the speedtest and here are the results: Ping 95 Download 0.17 Mbps, Upload 1.11 Mbps.

My son who is connecting via wireless is receiving these results: Ping 95, download 0.18Mbps, upload 1.64 Mbps.

This is confusing to me because even though the download speed dropped considerably when the router was involved, the upload speed is basically the same. What gives?

So, what should I do?

5 answers Last reply
More about modem router what
  1. Usually for high speed cable modem access you need a DOCSIS 3 modem, and I most often recommend Motorola Surfboard SB6121 as almost all ISPs list them as compatible.

    If you look here, you will see that your modem is not fully certified for high speed Comcast service like the SB6121:
  2. Yes, I also saw that on the Comcast site. However the confusing part is that when the computer was connected directly to the router via ethernet cable I got a download speed of 16.04 Mbps and upload of 1.73 Mbps. This would seem to be pretty much in line with the specs for my tier of service which say downloads up to 20Mbps and uploads up to 4 Mbps.

    The problem is when I go to the router. The upload speeds are pretty much the same but the download speeds drop to 0.17 Mbps.

    Also, according to the information on the Linksys forums, the difference between DOCSIS 1.1 and DOCSIS 2.0 is only evident in the upload speed -- they said it doesn't impact the download speed. Maybe this is bad information but several different threads on the Linksys forums say the same thing.

    Another quick much difference do the ethernet cables make? I just looked at my cables and I have CAT 5 between modem and router and also between one computer and the router. I have a powerline adapter hooked up to the router as well with a gray cable that has no label on it.

    I am just confused as to why the speeds seem fine when the same computer using the same cable is hardwired to the modem but when the same computer and cable are connected to the router the download speeds drop by a factor of 100!

    Thanks for your help:)
  3. A CAT 5 cable should be fine as long as it is not damaged, so sure check to see that the cables are okay.
  4. Realbeast:

    Thanks for the answers. I have switched out cables and nothing changes. I also posted this on the D-Link forums and they made the same suggestion you did about getting a new modem -- even the same one you mentioned:) The opinion there is that my old modem is not playing nice with my newer router.

    Time to shop!
  5. Cheapest I've seen on that modem is Amazon.
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