In short, the downside of the one-link-per-VLAN approach can be summarized as a lack of scalability. Although the one-link-per-VLAN design can be simple to initially configure, it can become very cumbersome as the number of VLANs (and therefore cables) grows.
![router on a stick commands router on a stick commands](https://www.practicalnetworking.net/wp-content/uploads/2016/10/rvlan-router-two-intf.png)
It is simple to understand and implement.It allows existing equipment to be redeployed in a switched infrastructure, consequently saving money.There are several advantages to using the one-link-per-VLAN approach:
![router on a stick commands router on a stick commands](https://www.interfacett.com/wp-content/uploads/2014/08/001-network-diagram-Cisco-Router.png)
Figure 11-2 illustrates the use of 10 Mbps router ports however, Fast Ethernet, Gigabit Ethernet, or even other media such as Asynchronous Transfer Mode (ATM) or Fiber Distributed Data Interface (FDDI) can be used. However, connections to the router use a separate link for every VLAN. Inter-Switch Link (ISL) trunks are used to connect the three switches together, allowing a single link to carry all three VLANs. In this case, the switched network carries three VLANs: Red, Blue, and Green. One of the earliest techniques for connecting a switched network to a router was the use of one-link-per-VLAN as shown in Figure 11-2. When discussing specific options for linking a router to a switched network, two alternatives are available: This “out to the router and back” flow is characteristic of all router-on-a stick designs.įigure 11-1 portrays the router connection in a general sense. It then travels back to the desired end station using normal Layer 2 forwarding. Inter-VLAN traffic must cross the Layer 2 backbone to reach the router where it can move between VLANs. Figure 11-1 shows a single link, the stick, connecting the router to the rest of the campus network. In this approach, traditional routers are connected via one or more links to a switched network.
![router on a stick commands router on a stick commands](https://ipcisco.com/wp-content/uploads/VLAN/Router-On-Stick-ipcisco.jpg)
Early VLAN designs relied on routers connected to VLAN-capable switches in the manner shown in Figure 11-1.