Level 1

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Slow Cable Modems - Everyone Please Read

I am a Broadcom employee. Broadcom makes cable modem chipsets. Some of these chipsets have a slight design flaw. I am not at liberty to divulge any technical details. However, I can tell you that using a cable modem containing one of these chipsets with your Mac will result in slow internet speeds. Apple is not at fault. I'm sorry to say that fixing these design flaws, which only affect Mac users is not a priority at this time.

I am a Mac user myself and am just as frustrated as you are with incompatible products. This is why I am coming forward and informing you of this problem with our products. Our chipsets are used in almost all of the most popular cable modems. I am including a partial list of the most recent and popular cable modems that use our chipsets which have this problem. I am unable to find any information about older and less popular cable modems. Please understand that I can not and will not divulge any more information. Thank you.

All Linksys Cable Modems
All Motorola Cable Modems except for the SB5120
All Scientific Atlanta Cable Modems

Posted on Aug 25, 2006 12:07 PM

62 replies

tsteph5

Level 1

45 points

Aug 30, 2006 12:23 AM in response to Karl Wojcik

i was able to verify that wcg200 does have docsis 2.0, but i can't figure out if it has the TI chipset. TI doesn't have a list of who uses their chipsets and linksys doesn't say who they use.

Aug 30, 2006 1:12 AM in response to Broadcom

I'm a little confused as to the configurations that this would affect. In today's world I think most people are connecting their cable modem to a router which in turn is where their Mac connects to. Therefore, the computer and the modem have no direct interaction with each other. Does the problem that you describe only affect those who are attaching their Mac directly to the modem itself?

Aug 30, 2006 4:06 AM in response to Joe Raymond

I'm a little confused as to the configurations that
this would affect. In today's world I think most
people are connecting their cable modem to a router
which in turn is where their Mac connects to.
Therefore, the computer and the modem have no direct
interaction with each other. Does the problem that
you describe only affect those who are attaching
their Mac directly to the modem itself?

Simple answer - No. It affects the Macs directly connected or through a router, doesn't matter.

Aug 30, 2006 2:30 PM in response to Karl Wojcik

I have a Motorola Surboard 5100. I double checked my speeds on my G4 800 mhz, running OS X10.4.7. I used www.speakeasy.net/speedtest. using the Chicago server my speeds are pushing 18000 kbps which is great. Choosing other server locations my speeds can plunge down to 1000 kbps. I checked my modem logs and all I see is warnings and criticals. What does all this mean? Now I don't know if I should go out and buy a modem or just keep leasing (at$3 a month) the one I have. Can anyone at least explain all the warnings below. THANKS

2006-08-30 15:59:28 5-Warning B605.10 Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID (EC=8)
2006-08-30 00:43:17 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
2006-08-29 04:45:28 5-Warning B605.10 Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID (EC=8)
2006-08-29 03:39:52 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
2006-08-28 16:45:46 5-Warning B605.10 Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID (EC=8)
2006-08-28 15:23:36 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
2006-08-28 12:29:06 5-Warning B605.10 Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID (EC=8)
2006-08-28 07:59:31 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
2006-08-27 23:12:24 5-Warning B605.10 Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID (EC=8)

Aug 30, 2006 2:34 PM in response to Christofer Michaels

I forgot to mention that the modem is connected to an Apple Extreme Base Station.

Broadcom Author

Level 1

0 points

Aug 30, 2006 3:56 PM in response to Karl Wojcik

Maybe Broadcom can answer the question as to why the
Cable modems are slower with Macs with cable modems
that do not have TurboDOX.

TurboDOX is a feature of Texas Instrument's new cable modem chipsets. These cable modem chipsets do not have the speed problems with Macs that our chipsets do and that is what you are seeing.

tbux

Level 4

1,691 points

Aug 31, 2006 5:28 AM in response to Karl Wojcik

Karl,

Thanks for the tip about the the Netgear FVS114 ! I picked up one and am thrilled with all the security features and easy set up.

Today is the last sale day at newegg.com, where this Firewall Router is availble for a total cost of $63;
http://www.newegg.com/Product/Product.asp?Item=N82E16833122081

naengwen

Level 1

0 points

Sep 4, 2006 1:48 PM in response to Christofer Michaels

If any of you are connected wirelessly to a router that goes into the modem, do you ever notice periods of time where your connection to the router will be just fine, but the speed will go from normal to 0 for a minute or so? I've been seeing this for a while now, and am wondering if this is at all related to the issues that people are having with the broadcom chipset. The modem my ISP gave me doesn't have a model number attached to it, so I can't really tell if its one of those on the list 😟

Sep 11, 2006 6:20 PM in response to Broadcom

how do you force full duplex on the airport?

I currently have the Mac Pro with Airport
Airport Extreme Base Station
Motorola SB5120 Cable Modem

BDAqua

Level 10

250,259 points

Sep 11, 2006 7:42 PM in response to f00fighters

According to Duane, Wireless is only Half Duplex...
http://discussions.apple.com/thread.jspa?messageID=2926714&#2926714

Broadcom Author

Level 1

0 points

Sep 16, 2006 1:37 PM in response to f00fighters

how do you force full duplex on the airport?

1. Open Macintosh HD:Applications:Utilities:AirPort Admin Utility
2. Select your AirPort Base Station
3. Click Configure
4. Enter your AirPort Base Station's password if it has one
5. Click Internet
6. Change WAN Ethernet Port to 100 Mbps / Full Duplex
7. Click Update

Broadcom Author

Level 1

0 points

Sep 16, 2006 1:38 PM in response to BDAqua

According to Duane, Wireless is only Half Duplex...

True, but I was referring to the "ethernet" connection between the modem and the AirPort Base Station.

BDAqua

Level 10

250,259 points

Sep 16, 2006 1:49 PM in response to Broadcom

Ahhh, yes! 🙂

tbux

Level 4

1,691 points

Sep 16, 2006 4:10 PM in response to Broadcom

How do you force full duplex on the connected Mac ?

Also, how do you do it if you are using a router ?

Broadcom Author

Level 1

0 points

Sep 16, 2006 4:59 PM in response to tbux

How do you force full duplex on the connected Mac ?

1. Open System Preferences
2. Click Network
3. Change Show to Built-in Ethernet
4. Click Ethernet
5. Change Configure to Manually
6. Change Speed to 100baseTX
7. Change Duplex to full-duplex
8. Click Apply Now

Also, how do you do it if you are using a router ?

The Motorola SB5120 should autonegotiate the ethernet settings correctly with your router unless it is an AirPort Base Station. However, if it does not, please see your router's documentation on how to force the correct settings.

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Slow Cable Modems - Everyone Please Read