-   Linux - Networking (
-   -   Ping delay problem (

arun79 08-27-2003 07:23 AM

Ping delay problem
I just installed a firewall/ router on my doorstop pentium 100 MHz 16 MB system, in which I have installed two Realtek RTL ethernet cards. I'm running Coyote linux on this box.

With this box, I used my old crossover cable to connect the Windows 98 box that my parents are using (Pentium 3 500 MHz 128 MB with a Netgear FA311 NIC).

The link worked fine and I am able to surf the net at much faster speeds on this network. But when I connected a old DLink DE 809TC hub that I got from a friend and tried UTP CAT5 cable (also old), I could not reach the net at all and the pings were coming back with huge delays (in the range of 250-1000 ms). I also see that the "collision" light on the hub keeps blinking.

What could be the problem? Will try to change the cables to new ones and check today.

Any inputs are welcome. Because I am extremely confused and unable to connect my box to the net (My parents getting to the net is pririty at my place.)

Rumblefish 08-27-2003 02:38 PM

You can't use a crossover cable with a hub, router, switch, or any type of intermediate hardware, to my knowledge. The idea of a crossover is to directly connect two machines and eliminate the hub if they are the only two communicating. Basically, a crossover cable has two of the wires's positions in the plug swapped so that traffic can flow properly without an interpretting piece of hardware in the middle. You're getting collisions because both boxes are trying to send outgoing data across the same wire, which is a no-no. Picture two guys at either end of a garden hose, each trying to blow into their ends of the hose at the same time, and you'll get a good mental image of what is going on. Try using standard eternet cable when plugging into the hub.

Blindsight 08-27-2003 02:51 PM

To clarify, you *can* use a cross over cable on same type devices, ie. computer to computer, as you know. But Also Router to Router, Switch to Switch, Hub to Hub, etc. (Unless you're using an 'uplink' port on some devices)

Conversely, you can't use a cross-over cable to communicate from Switch to computer, or computer to router.

arun79 08-28-2003 12:06 AM

I did not say that I connected my router to my hub with crossover cable. What I said was that when I used crossover cable to connect the router directly to my parents' system, it worked fine. But when I put the hub into the circuit with Straight Crimped (Untwisted Pair) CAT5 Cable connecting my parents' system to the hub and the hub to the router, there was a problem.

How can such a huge ping delay occur?

Please help....:confused: :confused: :confused: :confused:

arun79 08-28-2003 12:10 AM

An to add to the above, my router is nothing more than a Pentium 100 box with two NICs, one for the internet and one for the localnet. Not some fancy Cisco router

Robert0380 08-28-2003 12:45 AM

hubs suck and you will see a lot of collisions, but the behavior u describe seems a bit extreme. if the router box has tcpdump(text mode) or ethereal(gui mode) installed. you can use those tools to monitor network traffic to see what the deal is...or atleast get an idea. could even be a bad hub, especially if u just have 1 computer connected to the network end of it.

Blindsight 08-28-2003 08:55 AM

Is it dropping a lot of packets too, or just a delay?

Try switching the duplex to half on the router interface and on your parents system. It should be nothing more than, on the router, 'int ex/x', 'half-duplex'. Then, on your parents system, assuming it's windows, go into the network card properties and it's one of the.. I don't remember.. under the advanced tab, I think? you can set ethernet card properties including full/half duplex.

All times are GMT -5. The time now is 05:03 AM.