Layer 3 Switch VS. Router: Which to Choose?by Keelian J. Fiber Optic Networking
Speaking of layer 3 switch and router, everyone may be confused about the two terms, because they both take IP packets, examine the destination address and pass the packet according to routing rules. It seems that layer 3 switch is identical to a router in this way. Actually, they do have some difference not only in function, but also other aspects. This article will explain how they differ from each other and a better option will be suggested for your reference.
In general, a Layer-3 switch (routing switch) is primarily a switch (a Layer-2 device) that has been enhanced or taught some routing (Layer 3) capabilities and it was conceived as a technology to improve on the performance of routers used in large local area networks (LANs) like corporate intranets.
A router is a Layer-3 device that simply does routing only. In the case of a switching router, it is primarily a router that may use switching technology (high-speed ASICs) for speed and performance (as well as also supporting Layer-2 bridging functions).
Performance versus cost—Layer 3 switches are much more cost effective than routers for delivering high-speed interVLAN routing. High performance routers are typically much more expensive than Layer 3 switches.
Port density—Layer 3 switches, have more higher port count. Routers on the other hand typically have a much lower port density.
Flexibility—Layer 3 switches allow you to mix and match Layer 2 and Layer 3 switching, which means that you can configure a Layer 3 switch to operate as a normal Layer 2 switch, or enable Layer 3 switching as required.
WAN technologies support—Layer 3 Switch is limited to usage over LAN environment where Inter VLAN routing can be performed. However, when it comes to working on WAN and edge technologies, Layer 3 Switch lags behind. Router is the front runner in such scenario where WAN technologies such as Frame Relay or ATM need to be fostered.
Hardware/Software decision making—The key difference between Layer 3 switches and routers lies in the hardware technology used to build the unit. The hardware inside a Layer 3 switch merges that of traditional switches and routers, replacing some of a router’s software logic with hardware to offer better performance in some situations.
Now let’s look into the scenarios when should Layer 3 switch or router be used.
1. If you need to connect your Hub rooms and make a L3 decision and more Ethernet interfaces are required for direct server form connectivity, then you can use a switch.
2. If you need to connect your inter-offices via l2 circuits by the ISP you can directly terminate the link on the switch and configure routing on the same.
3. If you need more through-put and direct access and interVLAN communication, switch is the best option.
1. If you are connecting an ISP directly to provide internet, then router is the box you need to deploy.
2. If you need to build tunnels between your offices (connecting 2 offices over public internet securely ), then you need a router.
3. If you are a CE participating in MPLS configuration, then you need a router.
Having explained the mechanism of both a router and a Layer 3 switch, I guess you’ve already have an understanding of them. Simply put, they perform the same function but each have pro's and con's as to limitations. Generally, Layer 3 switches are primarily used in the LAN environment, where you need routing. Routers are used in the WAN environment. These days lots of people have started using layer 3 switches in WAN environment, like MPLS.
Created on Sep 20th 2017 02:53. Viewed 165 times.