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brooksp

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Problem connecting LAN's

Hi all,
I am having a problem maybe someone can help me with.
I am trying to connect 2 LAN’s together. The setup is as follows:
There are 2 rooms, each with 12 pc’s. each room is connected using 2 8port switches connected together by uplink cables. The pc’s have static ip addresses in the 192.168 range. Both rooms are on the same subnet.
The problem I am having is trying to connect the 2 rooms together. I have tried to run a crossover cable between a switch in each room but it doesn’t work. The rooms are about 50Meters apart, but that’s within the range for Ethernet. The “Link” lights on each switch just seem to blink intermittently when I connect them together.
Is it possible to connect switches in this way? As in switch 1 connected to switch 2 by uplink cable, connected to switch 3 by crossover cable, connected to switch 4 by uplink cable?
Do I need to put in a bridge and separate the 2 rooms? Or is it a problem with the distance?
For reference the PC’s are all running Win98.
Thanks for any help.
brooksp
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scampgb
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Hi brooksp,

This configuration should "just work".  There are no problems with the number of PCs or cabling distance, and a simple crossover cable between the switches should work.

What are the make & model of the switches?

Also, have you tried with a straight-through cable?  Some switches can be fairly intelligent with these things and have dedicated ports for it.

You might want to try this:

Room 1 : Switch 1 plugs into Switch 2 with a crossover cable between the ports
Room 2 : Switch 3 plugs into Switch 4 with a crossover cable between the ports

Switch 1 and 3 are connected to each other through the uplink ports.

I hope that this helps - let me know if you need any further help.
This is the proper way to do it and the distance should not be an issue.

What are the models of the switches? Do they have separate uplink ports in them? Do they have uplink ports on the back as part of a backplane

If you are using an RJ45 uplink port, you do not want to use a crossover cable. If it is just a regular port, you do.

Ensure that they are not already uplinked and you are creating a loop.

Also, once you think you have this working in layer two, ensure that you are using a 255.255.255.0 subnet on both sides.

Kent
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dstarfire

possibility one: most switches will have a special port (set off from the rest) for connecting to other switches. Try running an uplink cable from this port on one switch to a regular port on the other.  or use a crossover to connect the two uplink ports together.

It is entirely possible to link together several switches, though you'd want to use the uplink (I know that's not the right name for it, but I can't remember what the proper name is right now) ports, rather than just linking them together through the regular ports.

p.s. all switch to switch connections (through the regular ports) would require a crossover cable. In switches, each port is a seperate circuit.
Avatar of brooksp

ASKER

I also thought it should work.
The switches are fairly cheap, I think they are Dlink  and Zonet. I will have to check tomorrow when I get back to the office.
They have 9 RJ45 sockets, the last one is shared with the uplink. But there are pc’s only connected to 6 ports. And the communication between computers in each room is ok. I will review my settings tomorrow and see if I have made a mistake.
Will post make/model when I check.
Cheers
If you are using a crossover cable between rooms, don't use any uplink ports. Just a regular host port on both devices will do it.

If you use a regular cable, use an uplink port on one switch and a host port on the other.

The blinking link light is confusing. Please let us know which switch and type of port it is occuring on and what is happening on the other switch at the same time.

Thanks,

Kent
Hi, the uplinks port are usually using straight-cable.. not crossover. Hope this will help.

:))
connecting to LAN is very easy, the limit for the length of the cable from one switch to the

other is 100M(standard length). make sure that the computer has only one

NETWORK IP ADDRESS.(actually you can decide what kind of ip you want, i suggest use class C)

subnetting the given ip address will help to determine the correct

ip address of each computer including the subnet mask. its important

also when you have LAN topology.

if you want an ip subnetter go to this link below:
http://www.boson.com/promo/utilities/subnetter/ip_subnetter.htm

- hope this will add

- E M M A N

Room 1:  Straight through cable from uplink port of switch A to a regular port on switch B.

Room 2:  Straight through cable from uplink port of switch D to a regular port on switch C.

Options for connecting switch B to switch C:

a) Straight through cable from uplink port on one end to regular port on other end.
b) Crossover from uplink port to uplink port.
c) Crossover from regular port to regular port.

It's not clear whether what you've tried so far matches any of these three possibilities.

Room 1 ( Switch A )--- uplink port --> straight cable --- regular port --- (Switch B)
                                                                                                          |
                                                                                                                                                                             Switch B (Uplink) to Swich C (Uplink) using Straight Cable
                                                                                                               
                                                                                                          |
Room 2 ( Switch D) --- uplink ---> straight cable --- regular port --- ( Switch C)

You will not waste the regular port on Switch B and Switch C.

Some Dlink or other brands of switch came with default MDI only, some with both choice of MDI-X and MDI. If both uplink are same with either MDI or MDI-X, crossover cable needed. if not, you can use straight.

Hope this help. :))
Avatar of brooksp

ASKER

I finaly got it sorted.
I had the setup connected properly. The problem was the Ethernet cable was running along a cable duct with a electricity cable and i think there was some interference.
I dont know what to do about points in this case as nobody mentioned that it might be a possibility.
I got a lot of good suggestions so  i dont want to be unfair.
Thanks to you all

brooksp
Hi - glad that you got it sorted :-)

I suggest that you post a message in Community_Support asking them to PAQ/Refund your answer.
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Lunchy
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