VLANS cisco router/netgear switches.

[dennisjohnson104]

Router 1841

IOS 12.3

switch Netgear gs716t

Im not trying to get help with the netgear, i just figrued i would let you know what i was using.

I enable my vlan on my switch. I used vlan 2. gave the host in that vlan an ip address of 172.16.2.10/24. Then i configured dot1q encapulation on f0/0.2. Then gave it an ip address of 172.16.2.1/24. Now when i do a sh intf0/0.2 it says it is down and the protocol is down. I gave it the no shut command but still nothing any ideas?

[thisisshanky]

So you are trying to setup a trunk between netgear switch and the 1841 correct ?

On the netgear switches, I dont know if they support 802.1q trunking. The port that connects from the switch to the router needs to be a trunk (configured on both sides). Since this is a multi vendor environment, the trunking has to be 802.1q. So first check to see if you can configure the switch port connecting to 1841 as 802.1q trunk

PS: You are using only one vlan, you dont need to configure trunking and inter vlan routing, unless you have more vlans.

1841---fa0/0--cable--switch---host

You can simply connect the fa0/0 directly to the switch. No need to configure sub interfaces or trunking on the switch. Assing 2.1 to fa0/0 and 2.10 to the host.

HTH

[dennisjohnson104]

Yeah the switch supports trunking. I will have multiple vlans when im done. I just wanted to start off with 2 vlans. By default all ports on a switch are in vlan 1 right? if so then i just want configure vlan 2 and then route between them.

Thanks alot for your prompt response!!

[thisisshanky]

Assume dummy subnets as follows.

vlan 1 - 172.16.1.0/24

vlan 2 - 172.16.2.0/24

Router----switch----hosts

Cisco 1841 config

-----------------

int fa0/0

no ip add

int fa0/0.1

encap dot1q 1 native

ip add 172.16.1.1 255.255.255.0

int fa0/0.2

encap dot1q 2 native

ip add 172.16.2.1 255.255.255.0

Create 2 vlans on the netgear switch. Connect the fa0/0 of 1841 to the switch using straight through cable. Do the necessary configurations on netgear to support 802.1q trunking on this switch port. Assign the ip addresses to the hosts (as well as one management IP for the netgear switch - vlan 1 )

Hosts in vlan 1 will have default gateway of 172.16.1.1 and hosts in vlan 2 will have 172.16.2.1 as gateway.

HTH

[dennisjohnson104]

when i do

ip add 172.16.1.1 dot1q native

it only sticks on the last one i do.

When i do show run it only shows native on f0/0.2 172.16.2.1

[amit-singh]

Hi,

You just need to define only one Vlan as native. So use the command only on the subinterface whose VLan should be native on your switch.

Let us know, if you donot configure Dot1q trunking between switch and the router, does the port stays up/up on both the side.

regards,

-amit singh