03-12-2006 09:31 PM - edited 03-03-2019 02:14 AM
how switches routing between VLANs without any routing protocol?
03-12-2006 09:36 PM
Hi Mate,
When you configure SVI (Switch virtual interfaces) on a L3 switch, the switch will treat each subnet configured on the SVIs as a connected interface. Therefore, it know where each of the connected networks resides. It does not, therefore, need a routing protocol to route between these subnets.
If you have a more complicated network, with multiple routers, a layer 3 switch that does inter-vlan routing will need to use a routing protocol to exchange routes with the routers. But in a simple network, you can get away with just using a switch/router for inter-vlan routing without running any routing protocols.
Hope that helps - pls rate the post if it does.
Paresh
03-12-2006 09:42 PM
Hi,
Network devices in different VLANs cannot communicate with one another without a router/L3 Switch to route traffic between the VLANs.
Just go thro, this link to understand the concept with some configuration examples,
Rgs,
Balaji
03-12-2006 09:46 PM
Can i get any sample config please
03-12-2006 09:50 PM
With a L3 switch, you would have config such as the following:
interface VLAN10
description SVI for VLAN 10
ip address 10.1.1.1 255.255.255.0
!
interface VLAN20
description SVI for VLAN 20
ip address 10.2.1.1 255.255.255.0
The above will result in two directly connected routes being installed in the routing table:
10.1.1.0/24
10.2.1.0/26
Therefore, the switch will be able to route between nodes belonging to the above two subnets.
Hope that helps - pls rate the post if it does.
Paresh
03-12-2006 10:04 PM
Hi,
As a addition to Paresh, if u have router instead of L3 Switch,
create a subinterface in router where the uplink from the switch is connected,
In a switch,
interface FastEthernet0/1
description connectivity to router
switchport trunk allowed vlan 2000,1000
switchport mode trunk
!
interface FastEthernet0/2
switchport access vlan 2000
switchport mode access
!
interface FastEthernet0/3
switchport access vlan 1000
switchport mode access
!
In a Router,
interface FastEthernet0/0
description *** TO Switch *****
no ip address
duplex auto
speed auto
!
interface FastEthernet0/0.1000
description Connectivity to 1000 vlan thro. switch
encapsulation dot1Q 1000
ip address 10.10.10.1 255.255.255.0
!
interface FastEthernet0/0.2000
description Connected to 2000 vlan thro. switch.
encapsulation dot1Q 2000
ip address 20.20.20.1 255.255.255.0
!
Rgs,
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