I was configuring a pair of HP ProCurve 2530 switches last night and was created VLAN's. I created 4 VLAN's that I'm going to tag for port 24 where the switches will connect to each other. However, I'm a little confused.
On port 24, I went ahead and noted the VLAN's as tagged. Once I did that and the switches were connected, they could ping each other just fine through the IP's I had given them on those VLAN's (for example 10.100.0.2 and 10.100.0.3).
In the port configuration, I can put a port in a trunk group (for example, trnk1) and then go to the VLAN page where I can mark the VLAN's as tagged for the trunk (at this point, port 24 is missing, with trnk1 in its place). Pinging still works as expected when I do it this way also.
So what's the difference? Can traffic from a device on one switch to the second switch only pass when it's trunked? I don't have any devices yet plugged into these switches to really to test this.
What's the difference between just tagging the port versus tagging the trunk port I created from port 24 in my example?
Best Answer
Terminology is confusing here. The trunk you created has nothing to do with VLANs. Rather, it's a link aggregation mechanism to bond multiple physical circuits into one trunk. This functionality is referred to by different names: trunk, LAG, EtherChannel, etc.
So, yes, VLAN tags will happily transit a trunk port, just as they will a single standalone port.
So boil this down, you don't need a trunk here unless you are planning on needing to use multiple physical links between switches.