05-09-2007 07:35 AM - edited 03-05-2019 03:58 PM
Hi all,
I have 6 Catalyst 2950 switches that I am planning on configuring with 5 VLANS( VTP, Trunking, logical interfaces with separate subnets have been configured on the Router). The only clarification that I need is if I have to configure each VLAN with a separate subnet and if so where do I assign the ip subnet to the VLAN?
Thanks in advance.
Solved! Go to Solution.
05-09-2007 07:49 AM
Hi,
The configuration you want is called router on a stick. You configure trunk on the uplink port between your switch and your router.
Then you must have trunk encapsulation on your router and its on the router you assign subnets to your subinterfaces.
On the switch you configure the same vlan on the ports that belongs to the same subnet.
In short the vlan - subnet configuration is done at your router.
HTH
Do no hesitate to post a new question if you want config examples!
Regards,
Bjornarsb
05-09-2007 08:25 AM
Sadik
Yes you are correct that the encapsulation command on the logical inteface does specify the ID of the VLAN. This is how the assignment of subnet to VLAN takes place.
HTH
Rick
05-09-2007 07:41 AM
Sadik
Yes each VLAN should be configured with a separate subnet. The place to assign the ip subnet to the VLAN is in the logical interfaces on the router.
Each 2950 switch can have a single VLAN interface active and configured with an IP address. This is done to allow the switch to be managed remotely. Generally the switch addresses are in the same subnet and it is assigned to the management VLAN.
HTH
Rick
05-09-2007 07:49 AM
Hi Friend,
In addition to Rick's post 2950 is a layer 2 switch so you will not be able to create multiple logical interfaces on 2950 switch. Either you need layer 3 switch like 3550 and above or router where you can create sub interfaces for multiple vlan support.
It is always good to keep all your layer 2 switches like 2950 with same vlan interface/subnet for management purpose. As Rick updated you can only have one logical interface up and running on layer 2 switch which is 2950 in your case.
HTH
Ankur
05-09-2007 07:49 AM
Hi,
The configuration you want is called router on a stick. You configure trunk on the uplink port between your switch and your router.
Then you must have trunk encapsulation on your router and its on the router you assign subnets to your subinterfaces.
On the switch you configure the same vlan on the ports that belongs to the same subnet.
In short the vlan - subnet configuration is done at your router.
HTH
Do no hesitate to post a new question if you want config examples!
Regards,
Bjornarsb
05-09-2007 08:18 AM
Thanks to all for the prompt and concise clarification. I was confused on how the subnet on the router corresponds to the specific VLAN, but I now know that the logical interface is assigned the subnet ip and the 802.1q encapsulation is assigned the ID number of the VLAN. I hope I am correct!
05-09-2007 08:25 AM
Sadik
Yes you are correct that the encapsulation command on the logical inteface does specify the ID of the VLAN. This is how the assignment of subnet to VLAN takes place.
HTH
Rick
05-09-2007 08:27 AM
Hi,
Yes like this:
interface fastethernet2/0.20
encapsulation isl 20
ip address 10.1.20.1 255.255.255.0
ip pim dense-mode
interface fastethernet2/0.30
encapsulation isl 30
ip address 10.1.30.1 255.255.255.0
ip pim dense-mode
HTH, please rate all helpfull posts.
BR,
Bjornarsb
05-09-2007 09:31 AM
In addition to Bjornarsb's post this what you need to do for 802.1q encapsulation
Router
interface FastEthernet0/0
no ip address
duplex auto
speed auto
interface FastEthernet0/0.1
encapsulation dot1Q 1 native
ip address 10.10.10.15 255.255.255.0
no snmp trap link-status
!
interface FastEthernet0/0.16
encapsulation dot1Q 16
ip address 172.16.16.1 255.255.255.0
no snmp trap link-status
!
interface FastEthernet0/0.99
encapsulation dot1Q 99
ip address 192.168.180.50 255.255.255.0
no snmp trap link-status
Switch
interface FastEthernet0/23
switchport mode trunk
no ip address
interface Vlan1
ip address 10.10.10.12 255.255.255.0
no ip route-cache
-amit singh
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