Help Me Understand Switches

[olds]

<--- not a network person

We have a room where we run 10 laptops on a switch.
What I understand from my co-worker is the following:
One data port is set up for the switch.
The switch is set up for that data port.

If you plug in something other than the switch to the data port, you will "blow up" the port and it has to be reconfigured.

If you plug the switch into a port that is not configured for the switch, the switch will "blow up"and have to be reconfigured.

Any idea what he means? He doesn't know anything more that what I laid out.

I am not sure of the type of network we use. The switch is about 5 years old (and loud).
I work for the government so it's likely the equipment/technology we use is antiquated.

TIA

 

[azazel1024]

I think he has no idea what he is talking about. You can plug any networking device that works with 10base-t, 100base-tx, 1000base-t in to a switch that speaks that L1 standard (and also happens to do TCP too). Effectively if it has an RJ45 port, it can be plugged in to a switch...at least anything vaguely newish (~10 years old or so).

The only "blowing up" of a switch that will happen is if you create a loop. That means you connect a switch to another switch using more than 1 port. Exception is if you have loop detection or link aggregation setup on the switch, which requires a semi-managed or managed switch to do/have.

Think of it this way, normally any switch or networking device should only be connected to a switch or networking device through a SINGLE path. If there can be more than one path, it'll fail and lockup the switch. So you can connect switch 1 to switch 2 with a single port on each end. You are fine. If you connect them through two ports, the switchs are going to lockup (they start trying to passing traffic over both ports and flail/fail). You can connect switch 1 and switch 2 to switch 3 through one port and you are fine. You cannot connect switch 1 and 2 to each other and also both of them to switch 3. This will result again in two paths between the switchs and they'll go down hard.

Loop detection intelligent detects when more than one path exists and disables one of the ports (based on an algorithm for highest value path) until it detects that the un-disabled port goes down, then it'll re-enable the redundant port/path. Link aggregation is vaguely like loop detection (also called spanning tree BTW), except it allows the switch to work two ports (or more) as a "virtual" single port so that a loop doesn't form.

By data port, are you talking about the ethernet port on each laptop? Or do you mean an uplink port on the switch back to the core network? For the later, that is because if you plug something else in, the switch doesn't have a connection back to the core network again. If you just mean an ethernet port on a laptop to the switch...ummm...anything should be able to be plugged in, except another switch that would create a loop (connected in a way where a loop won't occur doesn't cause a problem).

 

[Gryz]

How is that switch connected to "the rest of the world" ?

Are you a small office/business, that has 10 computers, and they are going to be connected via that switch to a small router that does ADSL or Cable to an ISP ? In other words, you are your own setup ?

Or are you part of a larger organization ? And your 10 computers are just in one of the offices ? And you want to use the switch to connect more computers/devices that you were supposed/allowed to ? And the switch connects to the internal network of your larger company/office/business ?

If that second scenario is the case, then talk to the network admins. What is possible is not always what is allowed. Or what is expected. If your network admins expect you to connect 1 devices to their network, and you connect a switch with multiple devices behind it, then you are asking for problems.

 

[XavierMace]

Only thing I can think of is maybe they are doing MAC filtering so the port is looking for the MAC of the switch.

 

[lif_andi]

Could be a number of things configured on the port, but no ports will "blow up". At worst you'd have to shut down the ports in question and then turn them back on to get the thing going again.

 

[XavierMace]

Which I could see being described as "blowing up" to a non-networking person.

 

[pcgeek11]

Your Co-worker is clueless. Nothing is going to " Blow Up ".

 

[olds]

By port, I mean the ethernet connection you plug a cable into that normally is in a wall. In this case, it's in the floor, under a table.
The laptops are set up on a table to form a "command center" to manage large scale incidents to our transportation system.

 

[seepy83]

Sounds like Port Security in Shutdown mode. When an unexpected MAC address connects to those switch ports, the port is shutdown and requires manual intervention from the Network Admin to bring the port back up.

 

[olds]

Port security could be it.
Is there something that could happen to the switch? Are switches "configured"?

 

[imagoon]

Port security could be it.
Is there something that could happen to the switch? Are switches "configured"?

Managed switches have tons of configuration. The configs won't damage the switch but as mentioned many times here they may have port security, 802.1x authentication, CDP based security in the Cicso world, other things like trunking, various vlan configs, BDPU guard among others to make it "more difficult" to hook an unauthorized switch to be attached. Much of this can shutdown a port which could be called "blown up" by the underinformed