Desktop, Printer, UnManaged Switch connected to HP 2350 48S

[cspell]

We have recently upgraded and bought 2 hp 2350 48S switches. I have started moving connection from an older HP 4000 pro curve over to the new switches.

In our office, several clients have a smalll unmanaged switch connected to the network drop and then have a printer and a desktop connected to this small unmanaged switch.

Here is a breakdown of the equipment specs

Printer: 100 Mbs max

Dell PC: 1 GBs

Netgear Unmanaged Swtich: 1 Gbs

With everything connected, The PC inidcates 1GBs speed which seems expected but when viewing the port on the HP2350 using 'show int bri' I can see this port is running at 100 Mbs. 

If I just connect the PC to the port, I see the link speed on the HP switch is now 1Gbs. 

Is this expected behavior? I would have thought the link speed on the switch should show the speed of the cable to the network drop?

Thanks for any insight.

[parnassus]

The speed the new (and old) HP Switch shows on the port is the auto-negotiated one with the device it sees connected on the other side of that "network drop": so if there is an Unmanaged Gigabit Switch on the other side - on that network drop - the expected speed should be 1 Gbps if both Switches are Gigabit Ethernet capable (the old HP 4000 is not if I recall correctly).

This, obiouvsly, if all involved ports - of the Managed Switch - aren't set with a fixed Speed settings (which is non default).

The PC connected (via a Patch Cord few meters long, I presume) to the Unmanaged Gigabit Switch will probably always show you the 1 Gbps port speed. That's expected.

That's also happens if you connect that PC directly on the new HP Switch.

I hope to haven't misunderstood your example so here the question: What will happen if you connect your PC (with its 1 Gbps interface) to the "network drop" instead of directly to the new HP Switch's port?

Does the result change?

This practical test is to understand if the cable (directly connecting both the network drops <- to be verified!) is (or could be) partially/completely responsible of any sort of signal degradation.

if:

- involved Cable (and Patch Cords) is Cat. 6 certified (better than Cat.5E certified),

- involved Cable is shorter than (let's say) 90 m,

- PC/Unmanaged Switch *and* the new HP Switch both have all related port's speed set to "Auto" (e.g. Auto 10/100/1000),

then the auto-negotiated speed should be the fastest both devices are able to advertise and agree each others (so 1 Gbps).

[cspell]

Thanks for the Reply.

Indeed I did do some more testing, here is what happened:

1. plugged printer into network drop connector directly with net cat 6 cable. 

Result: printer is online operating at 100 Mbs according to HP 2350, which is correct as it's an older Dell printer. There are no errors shown in 'show log' command.

2. Plugged my test PC directly into network drop with new cat 6 (12' ) cable. This is a dell with a broadcom gigabit NIC.

PC is online but is showing 10 Mbs full duplex in the hp switch and also 10 Mbs on the PC. I'm attaching a screenshot of the console output.

For some reason, the connection is being throttled to 10 Mb. Both sides are set to auto negotiate. The NIC driver has no update. 

Is there some debugging I can put on the switch to see what could be happening?

Thanks!

[cspell · Accepted solution]

Issue Discovered.

Tested the line in the wall and wire # 7 is dead. This explains why it was working for 10/100 as well.

[parnassus]

Yep, glad you were able to discover the issue so fast.

Gigabit Ethernet requires all four wire Pairs and is very sensible to bad/inappropriate cabling/patching (including RJ45 jacks/connectors too): this explains why certified cabling (seen as a whole) and certified Patch Cords is somewhat a mandatory requirement to avoid these type of issues.