Adding a Switch used to be easy...

I've extended my wired ethernet network by running about 100 ft of cable from my office to another floor in my home.

Used jacks in the walls, punched down 568B, but it's basically just a jumper from the switch in my office to another part of the house.

Pin mapping tool says the cable is wired correctly and if I plug the cable from the wall into my MacBook Pro it works fine. Looking at the network settings it can find the DHCP server and set itself up correctly, loads internet content in a web browser etc.

If is plug the cable into a switch (DLink DGS 2205 5-port giga ethernet switch) and plug the laptop into that switch there's a problem. Eventually the Mac's networking cpanel finds the DHCP server but I cannot make connections -- everything just seems to time out. Also tried installing a router on the line instead of the switch, it can't seem to find the DHCP server at all. Tried two different routers.

I have a vague memory about Mac's doing some auto sensing and switching back when folks used patch or crossover cables ... it's making me wonder if something got wired wrong and that's why the MBP is the only thing that seems to be able to use the connection.

Any suggestions, things to check, or insight into why a MBP can use the cable but nothing else (routers, switches, etc) can?

Thanks!

Wire with short, pre-made cables from router to MacBook (expecting that to work).

Then router - switch - MacBook with pre-made cables. (All still working?)

mrplow said:

Wire with short, pre-made cables from router to MacBook (expecting that to work).

Then router - switch - MacBook with pre-made cables. (All still working?)

Click to expand...

Yes works fine. To be clear these are the connections:

Router --- switch (1) --- into wall (X) --- out of wall (Y) --- switch (2) --- MBP // no joy


Plugging the MBP into the router directly, into switch 1, into socket at wall Y all works.

Plugging switch 2 into switch 1 (by passing the wall run X to Y) works:


Router --- switch (1) --- into wall (X) --- out of wall (Y) --- MBP // OK

Router --- switch (1) --- switch (2) --- MBP // OK

Router --- switch (1) --- MBP OK

Router --- MBP // OK



It's only the combination of the wall run (X to Y) with switch 2 (or another router or a wireless access point) and then to MBP that doesn't work.

The run from X to Y is accomplished with two jacks punched 568B and about 50 feet of the same cable I'm using for the run from switch 1 to X. (Cat 6)

Using a line tester shows the X to Y run wired properly and I think I can support runs up to about 300 feet -- no way there's more than 100 feet in the whole run, router to MBP at it's longest.

Have the switches got uplink ports?

Do you get the same result if you take switch 1 out of the equation?

mrplow said:

Have the switches got uplink ports?

Do you get the same result if you take switch 1 out of the equation?

Click to expand...

Yes, hard to reach but I did try bypassing switch (1) thinking there may be some weird incompatibility. I plugged the wall run directly into an open port on the router. I got the same results:

Router --- switch (1) --- into wall (X) --- out of wall (Y) --- switch (2) --- MBP // no joy

Router --- switch (1) --- into wall (X) --- out of wall (Y) --- MBP // OK

Router --- into wall (X) --- out of wall (Y) --- switch (2) --- MBP // no joy

Router --- into wall (X) --- out of wall (Y) --- MBP // OK


The switch (2) has five equivalent ports.

When plugged in I get a green light on both plugged in ports, showing a connection.

There is also a speed indicator. It indicates a 1000 Mbps connection to the MBP and a 100 Mbps connection to the wall Y (everything is wired gigabit, I think the provider's router is the 100 Mbps limiting factor).

Found where problem was coming from. A small patch cable on the router. The cable worked, but using it brought the whole network on that side down to 100 Mbps and produced the behavior I was describing above.

After replacing it that segment of the network went back up to 1000 Mbps and the problem with the new run went away. I don't understand how it caused the problem, but I'm satisfied that the problem existed in the cable. The problem is gone by replacing it.

Thank you for your help!

Brilliant

Glad you got it sorted

I have seen this before. All it takes is one not very good cable to bring the whole thing to the ground! Good going on the troubleshooting!

Never thought about that when I read the initial post. Nice bit of troubleshooting.