Distribution switch question

[Fespino1]

Hello,

I have a question (first of many). I should mention that I'm new to networking so I apologize in advance if my question is stupid or does not make sense. I'm trying to understand how multiple switches can connect to a single switch (what i believe to be a distribution switch).

What i'm asking is this:

Do all vlans in the LAN have to exist in this switch?

are all ports in this switch trunk ports?

what would be the difference between the "regular" ports (where all switches are connected) and the uplink (the port going to a router or another switch)

Again, I apologize if this does not make sense but hopefully someone can explain this to me.

[Francesco Molino]

Hi

Don't apologise, there're no stupid questions. This is a community forum and we're all here to help each others.

The switch that connects to all other switches can be called a distribution switch or also a collapsed core (acting as core and distribution for networks that doesn't have the 3 layers core, distribution and access in a legacy network).
Downstream switches are called access switches.

Ports facing the router can be a trunk (multiple vlans), access port (untagged) or routed (L3 port).

Ports facing access switches can be trunk (most common on usual networks) or routed (if you have L3 access switches and you want don't want to span your vlans from the top to down).
When you configure them as trunk, you usually want to filter vlans per access switch and so you won't allow all vlans and limit only the one you need. We do this to avoid sending traffic for a vlan on a switch where no hosts are member of this vlan to make it simple.
In this topology, with trunk ports to access switches, your default gateway and inter-vlan routing reside to this distribution switch or to a core switch if the distribution switch is also trunked to the core.

I answered your question high level. Does that make sense?

[Fespino1]

Thank you very much.

By routed ports do you mean that all ports in the distribution switch (the ones facing access switches) would have an ip address (default gateway) assigned to this interfaces?

What about loops and stp? I'm still trying to get head around this subject. How stp relates to this if say I have the following:

3 access switches (connected to distribution switch)

1 distribution (connected to core)

1 core

Does my question make sense?

Again thank you for taking the time to answer this question.

[Francesco Molino · Accepted solution]

What i mean by routed interface is that all interconnecting interfaces will have an ip and traffic from access to another access (or distribution or core) will be done using a routing protocol (static or dynamic). In this topology, stp won't pass from the core to the distribution and to access.

In a more usual network, if core, distribution and access switches are connected over L2 trunk interfaces, then you'll need to setup stp by setting priorities in every switch (core would be the root, then distribution will be the secondary and access switches can be left with default priority value). You will also want to prevent an access switch becoming a root stp so you need to setup spanning-tree guard root command on interfaces facing downstream switches from the core to distribution and from distribution to access.
If you start in this area, there are some videos well done by networklessons. I highly suggest looking at it to understand how to set it up.

[Fespino1]

Thank you very much!

[Francesco Molino]

You're welcome