Desktop

Ask something
Discussion Locked

LAN speed weirdo

0 helpful
29 replies

by ozi eagle

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

Hi,
I have just acquired a new client with a strange problem.
3 computers networked p2p. 1 computer (called server) running XP SP2, the other two XP Home unsure as to release (though probably SP2)
The server has cable internet via Motorola Surfboard SB 5100 modem, connected via USB port. LAN separate connection via Intel (?) chips.
Now the funny bit.
When the LAN is set to 10Mbps internet works fine, as does the LAN (though slow).
Change LAN speed to 100Mbps and no internet connection, though LAN works OK. Ipconfig /all gives same results in both modes.
I need to get the LAN to work at 100 Mbps and the internetand am totally bamboozled. Any ideas?

29 replies

by black panther

I am not sure if the Motorola Surfboard is capable of speeds over 10MBS?

You may have to check with Telstra ( if you use them as the ISP )

by ozi eagle

Thanks,
I would think that the speed of the modem shouldn't affect the LAN or vice versa, as they are two separate connections, ie the modem is not part of the LAN. They have different IP ranges, submasks, DNS etc.

by hal 9000

Use a CAT 5 cable to connect the modem to the "Server" fit another Network card and run it off that as there are numerous issues with a USB connection. Just a word of warning here however if they have a Gigabit LAN connection on the server you'll have to use the same type of plug in card as a normal "cheap" one will prevent the system from working. Currently there is no way around this problem as Windows will not start in any mode so you can configure the cards separately.

Under ideal conditions the LAN speed should have no effect on the modem connection but again there are numerous problems with a USB connection.

I've personally fitted a similar type of modem to both Gigabit and 10/100 T Base LAM's without a problem as the speed of the modem is not affected by the speed of the network connection it is just how fast the Modem can feed the data to the LAN or transfer it up the modem will not accept speeds greater than it can handle so it is a "Network" problem that you are looking at here.

What type of M'Board is in the Internet gateway unit? If it is one of the older ones with USB 1 on-board it will appear to be slow over a network as the modem can download data to the USB port faster than the USB port can accept it. Have you tried disconnecting the rest of the computers and seeing if you have a decent Internet Connection Speed at the Gateway?

Lets know how you get on.

Col

by hal 9000

As you configured the modem via the USB port it may not recognize the Ethernet port. Whenever I have setup these things it has always been setup the modem on the Ethernet and then configure as required that way the IP and Sub Net Mask is correct for the modem as well as the LAN. I have done this type of connection on numerous times now and always without a problem and never seen the LAN drop in speed.

Perhaps it would be a good idea to clear the modem back to the Factory Defaults and setup again. As you didn't say if you ever had it working properly via the USB connection I'm taking it that you had it working and you already know that it works but have hit a brick wall with the setup. You also do not need the Modem Driver installed when you connect this way as the Ethernet connection is already supported and it is just a matter of resetting the IP and Sub Net address for the modem to work properly. Here Optus refuses to allow their ADSL and Broadband modems to be connected via a USB port and they have had way too many problems incurred and even taken out quite a few computers with the USB drivers.

Just a side thought here are you sure that the Network card is actually working? I know it is rare but some of the Realtech ones where a real pain with XP to get working properly and you had to move them to different PCI slots to get them to work properly. I have not run across this recently but it is worth bearing in mind as there may be a basic conflict that is preventing it from working correctly in the hardware. Just moving the card to a different PCI slot generally cures the problem.

I hope that is of some help.

Col

by ozi eagle

Thanks Col,
I've given up on trying to get the network to100Mbps. Its outside the work I was commissioned to do, anyway, just an annoyance that originally seemed easy to fix.
Tried everything, Motorola's instructions to reset the modem included. No go, just doen't want to connect via ethernet. Tried two different ethernet ports, same result.
Funny thing is I have another client with a similar setup (USB internet via SB5100 modem, separate LAN)and his works OK.

by ozi eagle

Thanks Col,
I've given up on trying to get the network to100Mbps. Its outside the work I was commissioned to do, anyway, just an annoyance that originally seemed easy to fix.
Tried everything, Motorola's instructions to reset the modem included. No go, just doen't want to connect via ethernet. Tried two different ethernet ports, same result.
Funny thing is I have another client with a similar setup (USB internet via SB5100 modem, separate LAN)and his works OK.

by jonathanpdx

Switch the connection from USB to Ethernet on the "modem" (wish they would stop calling them that) and make sure all the cables running to each workstation are the same type (most likely CAT-5). USB connections to cable "modems" are not necessarily as fast as specs indicate. Check all of the settings on the "modem", reset and re-run the configuration CD.

Personally, on a small P2P network, I would get a small switch and plug everything into that. Make sure each workstation is equipped with, at minimum, Windows Firewall, Anti-Virus software and at least 2 anti-spyware scanners. Your Motorola Surfboard SB 5100 will act as a firewall of sorts, too.

by sgt_shultz

often the internet routers are not capable of more than 10mb nic speed because that is several times faster than a t1 anyway. you want a 100mb, quit using the dsl modem as your switch. get them to pop for a 10/100 switch and plug everybody, including the router into that. it will talk 10mb to the router and 100mb to everyone else and bob's yer uncle. fast lan and fast as it can go internet.
always start with the specs, grasshopper...

by ozi eagle

Maybe you should start by reading the post correctly.
There is no modem / router, just a modem. The LAN is separate, and through a 100Mbps switch.

by gpmcdonald

I used a Motorola 5100 in a similar P2P setup. Plugged two nic's into the server and shared the internet connection. Windows set up the bridge. Everything else plugged into a Linksys 10/100 router. Only put firewall on the server and used NAT for the other computers. Internet went at 11 mbs and the rest of the network went at 100. All were running XP Pro SP1 at the time. In a different location now and using a DSL instead of Cable modem with the same setup except SP2 for everyone. Tried running the modem off the router, everything works but hate the hassle of doing firewalls on all the machines instead of just the server

by rcom

I agree with the USB issue. Connect with cat 5.

Are they using ICS you didn't mention how the connection is shared? The modem probably only communicates at 10Mps and that's not a problem. But if you connect the PC(s) directly to it then your the LAN is also stuck at that speed.

The better thing to do would be to connect the PCs to a router. Possibly have to clone the MAC address of the modem and share the connection that way. This will seperate the LAN and is more secure.

From the MFG's site.

<>

by ozi eagle

Hi,
Further to my post. The other two computers do not require internet access, so no sharing.
Have tried to connect via second NIC, but modem won't connect to internet, and there isn't any described way of setting up the modem (though I did come across a way to crack into it). Next step is to check with ISP why modem won't setup on Ethernet connection.
Thanks for all suggestions so far.

by jcptech

You will have to stop using the usb connection.
Get a router with 100/1000 switched ports connect the modem to the router and the computers to the router. TADA! Much better lan.
:)

by captg

Check the properties on the PCI adapter & make sure that the Link Speed & Duplex setting on the Advanced tab is set to Auto Detect.

I'm also curious what IPCONFIG returns, & if the Windows Firewall is activated.

by ozi eagle

See comment above.

Also if the link speed is set to Auto detect the link defaults to 100 Mbps and stuffs up the interent connection.

by ozi eagle

See comment above.

Also if the link speed is set to Auto detect the link defaults to 100 Mbps and stuffs up the interent connection.

This discussion is closed to new replies.