sundance-communications.com/forum Forums VOIP Phones & IP PBX Networking connecting 2 hubs together

Customer move to a new location -- moving a 16 port hub and a 8 port hub. The server is connected to the 16 port hub; 14 outlets are connected to the 16 port hub; a cable is connected from the 16 port hub to the 8 port hub. None of the outlets will work off of the 8 port hub; I can move the patch cord to a port on the 16 port hub and it works. Is there any port that has to be connected from one hub to the othe? Any help appreciated!!

Doug

You would take a port from the 16port and plug it into the (usualy port 8) of the 8port, there should be a uplink button to push also so your 8port will work.

[This message has been edited by dtmf (edited January 06, 2004).]

What DTMF is talking about is the cross-over port on the 8 port hub. In the old days, before hubs could talk to each other, they had to have a cross over port or cross over cable to communicate. At first is was cables, then the hubs had built in ports, then they had ports you could turn on and off by pushing a button. Now a days, most are auto sensing so you can typically plug into any port. Hubs are starting to go by the way side in favor of switches. Switches basically allow a faster through put of data. If you are buying one for a customer or looking for one, get a 10/100 switch instead of a hub.

One of your ports may be reserved for UPLINK. Connect that one to any other one But the Uplink port.

If your hub does not have an uplink port (one a toggle switch to make a port an uplink port) then you have to make an Ethernet crossover cable. Or buy one from CompUSA.

You can do a Google search for ethernet crossover and you'll be able to find a diagram on how to make one.

Ralph

Did you get it going Doug?

Is'nt a crossover cable simply wired 568a on one end and 568B on the other?

Thanks guy's for all the answers. No I don't have it working yet but I have not been back on site. There is mostly spare outlets plugged into it and Iam going back on site next week. I think it is the cross over cable that will be the problem.

Doug

Alas, didn't see this one till now:

If you're cascading an 8 port hub off of a 16 port hub, you'll want to use the uplink port of the 8 port unit, and connect that to any of the 1-16 ports on the main hub. For a non terminating device to communicate with another non terminating device, a crossover cable must be used. MDI/MDX.

If you have the chance, I would reccomend replacing both of these units with a 24 port switch. The agregate bandwidth of a 24 port switch is effectively 24 X the alotted bandwidth per port. That being said, if everything is running at 100MBit, or 100baseTX, then the achieved bandwidth would be 2.4GBit. Whereas, with a hub, the bandwidth of the plane is effectively the highest speed at any port, ie. 100baseTX.

Cost difference shouldn't be high, packet colissions will be much lower, and you won't have to mess with any funky uplink scenarios, which again reduce bandwidth.

Not to mention... a 24 port unit is most likely rackmount, and I'm not sure if they have a patch panel, but if they do... that too may be rackmount, providing you with a more professional looking solution.

That's just my two cents... hubs are terrible devices this day in age. In a nutshell, a hub broadcasts every request to every port, relying on the receieving end to check CRC and allow the packet to pass, whereas, a switch is an intelligent device and passes data based upon the recipient's MAC address, which lies in a table on the switch, thereby allowing it to cross reference destiation port to MAC address... much more efficient.

Avaya, I know just enough about networking to be dangerous and that has to be the most down to earth easy to understand instructions I have ever heard pertaing to hubs and switches. Hell, I can even understand that. Appreciate the info!

Avaya, thanks for the info on the switch. The 8 port hub do not have a port label uplink, so can I plug the cross over cable into any port on the 8 port hub or should it be plugged into port 1 or 8? I will check when I go back on site to see If Iam over looking a button to turn a port into a uplink port.
Thanks again guys for all the information.

[This message has been edited by dialtone (edited January 09, 2004).]

Think of a crossover cable as string with a tin can on either side from one house to another. No matter what room the string and tin can is attached to, you can still talk to one another, right? Yes... well, that's what a crossover cable is. 1-8 will work just fine. An uplink port just has the pins crossed for you already (or has a button to allow you to cross the pins over). Other than that, it's just like any other port... except in more expensive switches, which will have an uplink module... allowing you to put your choice of cards in, like a fiber module, or 100baseTFX, etc. Thanks for the compliments... I'm here to help.

The cross-over cable did the job. Thanks again for all the info.