Networking problem

Lemming

Hi guys,

I've got the following set up:

1). IBB[1] radio antenna (VL equipment) with little black POE[2] box
2). Shuttle SK43G ](running Fedora Core 3) acting as router/firewall with an additional Genius Network card (100 Base T)
3). LinkSys 4port switch
4). Rest of network

The set up (as works):

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IBB equipment feeds into my attic, where my router/firewall box is connected to it (cable distance is short - about 2/3 ft). A second cable runs from the router/firewall box into my room downstairs and feeds into the network switch. All other machiens then use the router/firewall box to connect to the internet via this switch.

The Problem:

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A problem arises where I attempt to bring the router/firewall box into my room and connect it to the IBB POE box using the long cable feeding through from the attic. It can't get a signal strong enough. Now this cable is, I would estimate somewhere between 20-30ft in length and I know that everything works just fine. The only alterations between my room & the attic is the length of cable used. This cable works just fine when used in the capacity of bridge between switch & router/firewall, so I know there isn't a problem with the cable.

I'm thinking that perhaps the IBB POE box operates on 10 Base T as opposed to 100 Base T and perhaps there is a limiting factor for the cable length?

Any inputs?

edit: For clarity ... this has nothing to do with wireless networking. The IBB end of things works just fine and its involvement starts and ends with the ethernet connector feeding from the radio antenna into the POE box. The POE box then is connected to the rest of the network via an additional ethernet interface provided on the POE box



[1] Irish Broadband (wireless)
[2] Power Over Ethernet - essentially a booster box for network traffic

Basquillech

There is a guide to wireless stuff on the new Argos catalogue!

Lemming

Basquillech wrote:

There is a guide to wireless stuff on the new Argos catalogue!

This has nothign to do with wireless. This has everything to do with "wired" networking. Please read the problem description again.

Snowbat

In other words, when you replace a short ethernet cable (running power over ethernet) with a long cable (running power over ethernet), something tells you that the IBB signal is too weak or not available? You think it is not a cable fault because the cable functions in another situation (not power over ethernet though).

They're both straight-through cables (not crosswired), right?

Power in POE runs on spare wires in the cable that are unused for ethernet. It is possible your cable has a break or bad contact only in the wires used for power but the other wires used for ethernet are fine. This would leave you with good ethernet but your IBB radio with bad or no power.

I'm thinking that perhaps the IBB POE box operates on 10 Base T as opposed to 100 Base T and perhaps there is a limiting factor for the cable length?

10BaseT and 100BaseTX will both work up to 100m (segment) so length is not the problem. You need at least Cat5 cable for 100BaseTX. 10baseT will work on Cat3, 4, and 5.

Lemming

Snowbat wrote:

In other words, when you replace a short ethernet cable (running power over ethernet) with a long cable (running power over ethernet), something tells you that the IBB signal is too weak or not available? You think it is not a cable fault because the cable functions in another situation (not power over ethernet though).

That pretty much sums it up, yes.

They're both straight-through cables (not crosswired), right?

Yes again.

Power in POE runs on spare wires in the cable that are unused for ethernet. It is possible your cable has a break or bad contact only in the wires used for power but the other wires used for ethernet are fine. This would leave you with good ethernet but your IBB radio with bad or no power.

Well, the Radio (unless you are referring to the POE box in which case disregard this entire paragraph) is seperate. Think of the POE box as a bridge between two seperate networks. Network A = the radio = hunkeydory and a non-issue in this discussion. Network B = internal LAN and not everything is hunkeydory when I attempt to do certaint things (namely the above description)

10BaseT and 100BaseTX will both work up to 100m (segment) so length is not the problem. You need at least Cat5 cable for 100BaseTX. 10baseT will work on Cat3, 4, and 5.

This is Cat.5 cabling.

Snowbat

Well, the Radio (unless you are referring to the POE box in which case disregard this entire paragraph) is seperate.

I assume the POE box feeds power in at one end of the cable to power your IBB radio which lives at the other end - I'm saying it is possible for your cable to be bad in such a way that the 4 wires carrying ethernet are fine but one or more of the 4 spare wires (that carry power in a POE setup) are broken.

zod

have you tried changing the speeds to manual 10 half/full duplex - I have a hazy recollection of an issue with the autonegotiation...

galwaydude18

Heres an idea do you have a network cable tester? If you do check it! As said above the wires for the ethernet may be working perfect the other wires for the poe may not be making proper contact with the RJ45 module!

Lemming

zod wrote:

have you tried changing the speeds to manual 10 half/full duplex - I have a hazy recollection of an issue with the autonegotiation...

Well I know it's not an issue with the network card at the other end since everything works just fine with another - shorter - cable.

I'll try lay my hands on a cable tester as per galwaydude's suggestion and post back what happens

galwaydude18

Hey dude did you get your hands on a network cable tester to check our you cables?

Lemming

Okay .... I just got my hands on an Intellinet Cable Tester and the results are as follows:

All LED lights that either fail to light up or turn red indicate a faulty pair.

On the short cat5 cable (currently in use between IBB POE box & firewall/router machine):
Standard Test (In sequence): 1&2, 4&5, 7&8, 3&6
Grounding Test: 3&6, 4&5, 7&8 (the GED also fails to light)

Now, this cable most definitely works with the set up that I want to use it should be added, except for the fact that it's far too short.

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On the long cat5 cable (currently in use between firewall/router machine and network switch):
Standard Test (in sequence): 1&2, 3&6, 4&5, 7&8
Test with 'Ground': 1&2, 4&5, 7&8 (as should be although GED also fails to light)

It should be added that this is the cable with which I am having issues getting to work in the set up I want (ie. IBB POE box <--- long cable ---> firewall/router <---> short cable ---> switch <--- rest of network)
Anyone want to intrepret those results?

galwaydude18

What is GED? If I knew what that does I might be better able to help you out!

Lemming

galwaydude18 wrote:

What is GED? If I knew what that does I might be better able to help you out!

I think the GED is the Ground Test LED

galwaydude18

A network cable tester doesnt test a network cable for a ground as they dont contain any ground wires! are both cable defo straight through?

bricks

The longer cable might have too much of a voltage drop over it than the short one. So it doesn't provide enough power for the wireless box.
Maybe try using a different long cable

Also there may only be just barely enough power coming out of the network card to supply the wireless box with a short cable and then when the long cable is used its just not enough. So you could try using a different network card to see if it provides more power.

BigEejit

I thought a POE box was needed at each end? ... dunno for sure, but have definitely seen them sold in pairs

galwaydude18

I doubt there is that much voltage drop! It's not like he's using a 100m cable!