The first interface is VLAN 10, IP address block- 192.168,1.0/24, Name-Admin.Let me elaborate on the components used in the above images.
So, let’s start how to set the router on a stick. I hope you may have studied the sketch so far. The three VLAN PCs are in different colors, and the trunk ports are marked by red color in the figure. I hope, at the end of this article, you should be able to configure it with ease. For your convenience, I shall explain it to you in sequence. I suggest you open it in a different tab and observe it. Router on a stick: The topologyįirst, have a look at the sketch below, it’s a bit larger to view though. Moreover, the router performs more sophisticated functions more efficiently like NAT, Access control, VPN management, etc. When you have segments of the network in a geographically dispersed area, the traffic must go through a gateway like a router. Like they are designed to work in ethernet only, on the other hand, a router supports several protocols and standards. then the layer-3 switch is a better choice. If you are using the network within proximity-a campus, or different floors of a building, etc. Of course, the layer-3 switch is not as versatile as a router, but it is more affordable.
The layer-3 switch or a router- the choice depends on the purpose, services, and the topology. One may choose a layer-3 switch for inter VLAN routing. Each sub-interface is a dedicated channel for each VLAN. The main interface G0/0 is sub-divided into the sub-interfaces as G0/0.1, G0/0.2, and G0/0.3. It virtually accommodates three different paths in a link each path dedicated to a specific VLAN. See the link between the switch and the router. All the lines shown here are the trunk ports.
The different VLANs aggregates in a switch, those VLANS are further connected to an interface of the router. Please note the colors used in the diagram each color represents a specific VLAN. The above image illustrates the fundamental of the router on a stick. For more information about the frame tagging, refer to the blogs given in the links above. There are two possible methods of encapsulation in Ethernet, the ISL and IEEE 802.1q. We also have to specify the encapsulation method. As we have seen in the last post, the switch trunk port by default carries the tagged frame of all active VLANs, but in the case of a router, we explicitly have to mention the VLAN association of each sub-interface. Here we shall configure three sub-interfaces on the Gigabit Ethernet link of the router. Each sub-interface carry specific VLAN traffic, you have to configure sub-interfaces as much as the number of VLANs. In router on a stick configuration, we divide an IP interface of the router to sub-interfaces. With the help of the router, we can maintain the legacy of layer 2 VLAN, i.e., keeping the broadcast domain separate for each VLAN, and they will also be able to communicate as well when required. Now, we shall try to introduce a Layer-3 device into the VLAN. In the last blogs, we have covered the VLAN configuration and trunk creation, and An overview of VLAN. Also known as a one-armed router, it is the technique to allow inter vlan routing between the VLANs. Troubleshooting router-on-a-Stick Inter-VLAN Routing Configuration.The ‘ Router on a stick‘ is a method to transport multiple VLANs over a single router link. How to configure Inter-VLAN routing on Cisco Router ■ A router on a stick is configured with a subinterface for each VLAN and 802.1Q trunk ■ Inter-VLAN routing using a router on a stick utilizes an external router to pass traffic Router R1 has a separate interface configured for each of the VLANs. PC1 and PC3 are on different VLANs and have IP addresses on different subnets.ģ. The figure above show a traditional inter-VLAN routing:ġ Traffic from PC1 on VLAN10 is routed through router R1 to reach PC3 on VLAN 20.Ģ. Devices on those VLANs communicates with each other via the router. When using a router to facilitate inter-VLAN routing, the router interfaces can be connected to separate VLANs. This subnet configuration enables the routing process in a multi-VLAN environment. One of the ways of the ways to carry out inter-VLAN routing is by connecting a router to the switch infrastructure. VLANs are associated with unique IP subnets on the network. There is a way to permit these computers to communicate it is called inter-VLAN routing. To allow devices connected to the various VLANs to communicate with each other, you need to connect a router.Īs we’ve learned that each VLAN is a unique broadcast domain, so, computers on separate VLANs are, by default, not able to communicate. In the previous pages, we learned about how to configure VLANs on a network switch. We define inter-VLAN routing as a process of forwarding network traffic from one VLAN to another VLAN using a router or layer 3 device.