VLAN Scope

[andrewburridge]

Hi all, a quick question on the underlying functionality of VLANs in Meraki switches, in terms of scope.

I couldn't find any good documentation on this, if there is, feel free to point me in the right direction.

Say for example, I have a switch setup as follows:

S1--------------S2--------------S3

With trunks between them, default settings, no restrictions on what VLANs are allows on the trunks.

I configure an access port in VLAN 10 on S2, and also S3 in order for communication between 2 hosts that are patched into the relevant switch.

I'll use Cisco language, because that's what I'm familiar with. In the scenario above, assuming no VTP, VLAN 10 will then exist in the VLAN database of S2 and S3 because they both have an access port in that VLAN. VLAN 10 wouldn't exist in the VLAN database of S1 because it doesn't have a port in that VLAN.

Does this still apply to Meraki? Or does the very act of configuring a VLAN in a port on one switch in a given network propagate it to all switches, via some kind of mechanism similar to VTP.

Basically, is the broadcast domain of VLAN 10 limited to S2 and S3 in the above scenario, or does it also include S1?

Thanks.

[raj.yarlagadda@meraki.com · Accepted solution]

@andrewburridge The vlans will be spanned to all the switches in that particular network and the broadcast traffic will be passed over. The reason for that is to allow the clients connected to other access switches to be able to pass traffic across.

For example, let's take your analogy, if S1 is doing L3 and acting as the default gateway and if you have access ports on S3 configured for VLAN 10 but not on S2, the clients connected in VLAN 10 on S3 will still get an IP address from the DHCP server on S1 (Possible because broadcasts are allowed) and they will be able to go out to the Internet.

Cheers!

Raj

[andrewburridge]

Thanks Raj, appreciate the quick response.

[jdsilva]

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@andrewburridge wrote:

Does this still apply to Meraki? Or does the very act of configuring a VLAN in a port on one switch in a given network propagate it to all switches, via some kind of mechanism similar to VTP.

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Yes, but that mechanism is 100% pure, refined, fluffy Cloud.

[andrewburridge]

So so fluffy!

[nuo]

I really like the way VLAN's are handled in Meraki Dashboard.