View Full Version : ch. 11

05-21-2010, 12:29 PM
my question was in figure 11.15 where it shows mutiple vlans hooked to switches and then those switches hooked to main switch and then hooked to router. since all the vlans are differnet subnets how does the router sort out the traffic...? I show only one input to router? i guess with ISL or 802.1Q? Also, the mention that you could have to it to where users from differnt vlans can access server without crossing layer 3 device...? I understand that server would plug into its own trunking port on the switch.. My basic question is can you have more than one trunking port on a switch. ie. the one that connects the switches together and one hooked to server?

one more question for this post:
the part that says that vlans present security challenges because all users can see all devices on layer 2. I don't get that becuase i thought that vlans broke up broadcast domains and collision. How could computers on seperate vlans see each other?:confused :

sorry for all the questions. Im going to take break for couple of days

Big Evil
05-21-2010, 12:52 PM
What page is this mate?

05-21-2010, 07:12 PM
I believe you are talking about fig 9.4 on pg 557 sixth ed.

1st question: to route between the vlans you need a router. In this case you would use what is call a "router on stick" where the 1 interface is broken up into subinterfaces. Yes this interface on the router and the switch must have trunking setup with 802.1q or ISL

I believe that a trunk carries all vlan traffic. I am not sure but I think that the server must also support a trunking protocal like 802.1q or ISL.

05-22-2010, 09:41 AM
Appreciate you taking the time to answer. This figure is on page 357 fig 11.15. ; however, i think you answered my question. that is interesting you have to set up 8021.q or ISL on the router too.