Issue trunking vlan's from one sg200 switch to another.
Posted on 2014-08-23
I am still learning vlans. I have the concept down and was overjoyed when I thought I understood it enough to use it.
Using a single switch I can create 2 vlans (10&200), separate the traffic and everything is good. When I try to "trunk" those vlan's to another switch things break down. These are cisco Sg200 switches.
On switch 2 (SW2) we have port 2 going to a unifi access point. Switch 2 port 1 goes to switch 1 port 4. Switch 1 port 1 goes to router that provides dhcp & routing for the vlans. It looks like this;
[ap] eth1----eth2 [SW2] eth1-----eth4 [SW1] eth1---eth2 [router] eth1----[modem]
I think the issue may be tagging, but when it doesnt work using wireshark doesnt help.
The vlans exist on both switches. On SW2 ports 1&2 are trunk ports tagged 10&200. On SW1 ports 8 & 4 &1 are trunk ports tagged 10&200. If I move the AP to SW1 eth8, things works like they should. SSID 2 &3 use vlan 10&200 respectively. When i move the AP to SW2 eth2 it doesn't work.
I thought trunk ports carried the vlans from switch to switch. I thought the interfaces had to be tagged so the next switch would know what vlan to put them in. Apparently i have something wrong since it doesn't work properly.
Where have i gone wrong?