ccfc1986
Posts: 3
Joined: Tue Jul 08, 2014 5:51 pm

networking question - oddities

Tue Jul 08, 2014 5:58 pm

Hey All,

I am having a networking issue with the Raspberry Pi. Basically i have the following setup currently.

Office:
Modem -> Router -> Switch (GIG)

From the Office, i have a cable plugged into a punched ethernet socket/port. From that, the cable goes into my attic. In the attic i have a 5 port switch (GIG). From this switch, i have a cable dropped into my master bedroom. This comes directly through the wall.

Now, when i plug in the cable from the switch in the office (which goes into the wall) into my laptop, i get a connection. When i connect my laptop to the cable from teh office->attic directly, i get a connection. When i use a brand new eth 5e cable on a port on the switch to my laptop (wih the table from the office plugged into the switch), i get online/connection. When i connect the cable going to the master bedroom to the switch, and plug in the laptop in the master bedroom (again direct attic switch->laptop) i get a connection.

Here is the weird part. When i plug in the cable in the master bedroom (connected to the switch in the attic->office wall->office switch), the Pi does not recognize the connection.

If i use a cable from the office switch, and take it to the master bedroom and plug in the Pi, the connection works just fine.

So can anyone explain to me why the connection would work on the laptop (Lenovo Y510p) but would not work on the Raspberry Pi?

Thanks for any and all input.

User avatar
joan
Posts: 14259
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: networking question - oddities

Tue Jul 08, 2014 6:58 pm

The Pi has a 10/100 Ethernet port. Are you trying to connect it to a Gigagbit port?

ccfc1986
Posts: 3
Joined: Tue Jul 08, 2014 5:51 pm

Re: networking question - oddities

Tue Jul 08, 2014 7:00 pm

Yes. Connecting the Pi to my Office 10/100/1000 switch works just fine. Connecting it to the cable coming from the switch in the attic (10/100/1000... attic switch->punch plate in wall->office switch) does not work.

User avatar
AndrewS
Posts: 3625
Joined: Sun Apr 22, 2012 4:50 pm
Location: Cambridge, UK
Contact: Website

Re: networking question - oddities

Tue Jul 08, 2014 7:18 pm

I don't have any gigabit ethernet equipment myself, but I wonder if your problem might be related to https://github.com/raspberrypi/firmware/issues/217 ?
Perhaps the Raspberry Pi's NIC gets on "better" with some gigabit switches than others? :?

User avatar
ilguargua
Posts: 73
Joined: Thu Jun 19, 2014 8:14 pm
Location: Livorno - Italy

Re: networking question - oddities

Tue Jul 08, 2014 7:32 pm

ccfc1986 wrote: So can anyone explain to me why the connection would work on the laptop (Lenovo Y510p) but would not work on the Raspberry Pi?

Thanks for any and all input.
Just a (maybe) stupi question : since you are using some wall outlet, are you shure they are properly cabled ? Have you tested them with a proper instrument? If some couple of wire are swapped your laptop (that I suppose has a G Eth) is capable of autosense the connection and use it anyway, but not the Pi.

Just my 2 cent (in an orrible english)

Cheers,

Ale.

ccfc1986
Posts: 3
Joined: Tue Jul 08, 2014 5:51 pm

Re: networking question - oddities

Tue Jul 08, 2014 9:28 pm

That doesn't seem to matter. Plugging in the Pi directly into the office switch works perfectly. Testing the switch in the attic, i get the internet just fine. There might be a weird setting on the Pi that is preventing network connectivity if going through multiple switches or something? The switch in the attic is a TP-Link 10/100/1000 switch.

As a side note, i just tested the connection from the wall outlet (punched ethernet port) with a ethernet cable. I plugged in my wire tester in the office, and plugged the other end in the bedroom (where the Pi would plug in). All the lights 1-8 light up except light 6. So maybe there is something wrong with the cabling? Is that something the PC can handle but the Pi is unable to? Can i test a cable route through a switch correctly? Is that supposed to work?

Thanks again.

User avatar
rpdom
Posts: 15184
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: networking question - oddities

Wed Jul 09, 2014 4:26 am

ccfc1986 wrote:As a side note, i just tested the connection from the wall outlet (punched ethernet port) with a ethernet cable. I plugged in my wire tester in the office, and plugged the other end in the bedroom (where the Pi would plug in). All the lights 1-8 light up except light 6. So maybe there is something wrong with the cabling? Is that something the PC can handle but the Pi is unable to? Can i test a cable route through a switch correctly? Is that supposed to work?
Basic network cable testers aren't designed to run through a switch. They just test from one end of a cable to the other.

If the cable is showing that pin 6 is not connected then it is faulty. A standard 100 Mb connection only uses pins 1, 2, 3 and 6, so if 6 is faulty it won't work. A 1000 Mb connection uses all 8 wires, but may be able to function (depending on the hardware, and possibly at a reduced speed) if one of the wires is broken.

johndough
Posts: 254
Joined: Sun Jan 13, 2013 2:00 pm

Re: networking question - oddities

Wed Jul 09, 2014 10:27 am

Basic network cable testers aren't designed to run through a switch. They just test from one end of a cable to the other.

If the cable is showing that pin 6 is not connected then it is faulty. A standard 100 Mb connection only uses pins 1, 2, 3 and 6, so if 6 is faulty it won't work. A 1000 Mb connection uses all 8 wires, but may be able to function (depending on the hardware, and possibly at a reduced speed) if one of the wires is broken.[/quote]
Hi

Absolutely.

Pin Description 10base-T 100Base-T 1000Base-T
1 Transmit Data+ or BiDirectional TX+ TX+ BI_DA+
2 Transmit Data- or BiDirectional TX- TX- BI_DA-
3 Receive Data+ or BiDirectional RX+ RX+ BI_DB+
4 Not connected or BiDirectional n/c n/c BI_DC+
5 Not connected or BiDirectional n/c n/c BI_DC-
6 Receive Data- or BiDirectional RX- RX- BI_DB-
7 Not connected or BiDirectional n/c n/c BI_DD+
8 Not connected or BiDirectional n/c n/c BI_DD-
network cable pinouts.PNG
network cable pinouts.PNG (9.45 KiB) Viewed 1036 times

Return to “Troubleshooting”