On Thu, 15 Sep 2005 16:36:34 -0400 David Kreuter <dkreuter@xxxxxxxxxxxxxxxx> wrote: > Using 802.1q is it possible for users on two different networks to be on > the same vlan? I'm assuming that all switches support the 802.1q spec. > For example if user1 is on network 1.2.3.x and user2 is on network > 192.168.0.x can user1 and user2 be on the same VLAN, say VLAN 11? > And therefore hear the broadcasts destined for that vlan? And others > hosts on the same networks with VLAN 11 membership will not. > Thanks, David > Yes. VLAN seperates 1 layer 2 broadcast domain (e.g. eth0) into multiple independent layer 2 broadcast domains. You can have multiple addresses over eth0, e.g. eth0 = 192.168.0.1 eth0:1 =192.168.1.1 eth0:2 =192.168.2.1 And likewise you can have multiple addresses over eth0.11, e.g. eth0.11 =192.168.10.11 eth0.11:1=192.168.11.11 eth0.11:2=192.168.12.11 However, if you're going to have multiple subnets on the *same* VLAN there's little point in using VLANs. The whole idea of VLANs is to seperate different subnets so that they can share the same medium without hearing eachothers traffic. If you're going to put different subnets on the same VLAN then you may as well not use VLANs at all. Alex
