Layer 3 Switch VS. Router

In the OSI model, we know that traditional network switches operate at Layer 2 while network routers operate at Layer 3. Besides, switches are understood to be forward traffic based on MAC address, while routers perform the forwarding based on IP address. Layer 3 switches have a lot in common with traditional routers: they can also support the same routing protocols, inspect incoming packets and make dynamic routing decisions based on the source and destination addresses inside. For this reason, many networking beginners are puzzled over the definition and purpose of a Layer 3 switch. So what is on earth Layer 3 switch and how is it different from router?

Layer 3 Switch

Layer 3 switch is also called multilayer switch. It is a specialized hardware device used in network routing, which is conceived as a technology to improve network routing performance on large local area networks (LANs) like corporate intranets. A Layer 3 switch is both a switch and a router. So Layer 3 switch is a switch that can route traffic, and a router with multiple Ethernet ports has a switching functionality. It can switch packets by checking both IP addresses and MAC addresses. On this account, Layer 3 switches separates ports into VLANs and perform the routing between them, in addition to supporting routing protocols such as RIP, OSPF and EIGRP.

Layer 3 switch

Layer 3 Switch VS. Router

From the basics of Layer 3 switch, it may seem to perform the same functionality with the router. In fact, they have some key distinction facts. The key differences between Layer 3 switches and routers lay 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. The table below illustrates the differences between Layer 3 switch and router.

Layer 3 Switch VS. Router

Main Differences:
  • Cost – Layer 3 switch is much more cost effective than router for delivering high-speed inter-VLAN routing. High performance router is typically much more expensive than Layer 3 switch.
  • Port density – Layer 3 switch has much higher port count while router has a lower port density than Layer 3 switch.
  • Flexibility – Layer 3 switch allows you to mix and match Layer 2 and Layer 3 switching. It means that you can configure a Layer 3 switch to operate as a normal Layer 2 switch.
  • 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 switch and router lies in the hardware technology used to making forwarding decision. Layer 3 switch uses ASICs for forwarding decisions. Conversely, the router makes forwarding decisions based on hierarchical Layer-3 addresses.
Layer 3 Switch with VLANs

As here is mentioned the VLAN, so let’s talk about it firstly. A VLAN (virtual LAN) is a logical subnetwork that can group together a collection of devices from different physical LANs. VLANs can improve the overall performance of busy networks. So they are often set up for improved traffic management by larger business computer networks. With a VLAN, traffic can be handled more efficiently by network switches.

Each virtual LAN must be entered and port-mapped on the switch. Routing parameters for each VLAN interface must also be specified. Some Layer 3 switches implement DHCP support that can be used to automatically assign IP addresses to devices within a VLAN. Alternatively, an outside DHCP server can be used, or static IP addresses configured separately. The diagram below shows an example of a layer 3 switching routing between VLANs through its two VLAN interfaces.

Layer 3 Switch with VLAN

These switches are most commonly used to support routing between virtual LANs (VLANs). Benefits of Layer 3 switches for VLANs include:

  • Reduction in the amount of broadcast traffic
  • Simplified security management
  • Improved fault isolation
Conclusion

From what we have discusses, Layer 3 switch may be more preferable in result of its capability of routing and switching. Besides, it can perform as a top of rack device and a distributed core switching layer at the same time. This reduces the L2 complexity of the client access layer, which makes the network more reliable and easier to manage. FS.COM can provide a comprehensive, scalable and secure portfolio of switches for enterprise and service provider networks. There are also a huge stock of compatible fiber optic transceivers and cables. For more details, please visit www.fs.com.

How Much Do You Know about Ethernet Switches?

Today, all plants are virtually networked via Ethernet. High requirements are placed on the network infrastructure and network components. Ethernet switches are the integral piece of IT infrastructure, capable of receiving, processing and transmitting data between two devices connected by a physical layer. Due to the increasing application of big data analytics and cloud-based services in various end-user segments, data centers are envisaged to fuel the adoption of Ethernet switches. The augmented global demand for data centers is the key driver for the growth of Ethernet switches market. To satisfy the large and ever-increasing market for Ethernet switches, there are many varieties of switches offered different purposes. This article will help you get a deep understanding of the different types of Ethernet switches.

What is an Ethernet Switch?

A Ethernet switch is a tool for connections between the systems and equipment to forward data selectively to one or more connected devices on the same network. These connections are generally created through the use of structured cabling that links both the station side and the device that you are trying to share data with, such as a server or another computer. In this way, Ethernet switches can control the flow of traffic passing through a network, maximizing the network’s efficiency and security. More advanced Ethernet switches, called managed switches, are also capable of providing additional functions, such as network load balancing, address translation or data encryption and decryption.

FS Ethernet switches

How Dose an Ethernet Switch Work?

Ethernet switches link Ethernet devices together by relaying Ethernet frames between the devices connected to the switches. By moving Ethernet frames between the switch ports, a switch links the traffic carried by the individual network connections into a larger Ethernet network. Ethernet switches perform their linking function by bridging Ethernet frames between Ethernet segments. To do this, they copy Ethernet frames from one switch port to another, based on the Media Access Control (MAC) addresses in the Ethernet frames. Ethernet bridging was initially defined in the 802.1D IEEE Standard for Local and Metropolitan Area Networks: Media Access Control (MAC) Bridges. The standardization of bridging operations in switches makes it possible to buy switches from different vendors that will work together when combined in a network design. That’s the result of lots of hard work on the part of the standards engineers to define a set of standards that vendors could agree upon and implement in their switch designs.

diagram of Ethernet switches connections

Different Types of Ethernet Switches

Ethernet switches are broadly categorized into two main categories – modular switches and fixed switches. Modular switches allow you to add expansion modules into the switches as needed, thereby delivering the best flexibility to address changing networks. Fixed switches are switches with a fixed number of ports and are typically not expandable. This category can be broken down even further into unmanaged, lightly managed, and fully managed.

Unmanaged Switch

An unmanaged switch is mostly used in home networks and small companies or businesses, as it is the most cost effective for deployment scenarios that require only basic layer 2 switching and connectivity. The unmanaged switch is not configurable and have all of their programming built in. It is ready to work straight out of the box. And it is the easiest and simplest installation, because of its small cable connections. An unmanaged switch is perfect in this situation since it requires the least amount of investment with regards to both expense and time.

Smart Switch / Lightly Managed Switch

A smart switch is the middle ground between the unmanaged and fully managed switches. These smart switches offer limited customization, but do possess the granular control abilities that a fully managed switch has. In addition, smart switches offer certain levels of management, quality-of-service (QoS), security, but they are lighter in capabilities and less scalable than the managed switches. Smart switches tend to have a management interface that is more simplified than what managed switches offer. They also offer the capability to set up options like Quality of Service (QoS) and VLANs, which can be helpful if your organization has VoIP phones, or if you want to segment your network into work groups. Therefore, smart switches are the cost-effective alternative to managed switches. They are still valid choices for the regular consumer, as they are generally easy to use and you can glean a bit more information off of them on how your network is configured compared to unmanaged switches.

Fully Managed Switch / Enterprise Managed Switch

Managed Layer 2 Switch: A modern managed switch provides all the functionality of an unmanaged switch. In addition, it can control and configure the behavior of the device. This typically introduces the ability to support virtual LANs (VLANs), which is why almost all organizations deploy managed switches versus their cheaper alternatives.

Managed Layer 3 Switch (Multilayer Switch): This type of switch provides a mix of functionality between that of a managed Layer 2 switch and a router. The amount of router function overlap is highly dependent on the switch model. At the highest level, a multilayer switch provides better performance for LAN routing than almost any standard router on the market, because these switches are designed to offload a lot of this functionality to hardware.

data-center-network-architecture

Managed switches are designed to deliver the most comprehensive set of features to provide the best application experience, the highest levels of security, the most precise control and management of the network, and offer the greatest scalability in the fixed configuration category of switches. As a result, they are usually deployed as aggregation/access switches in very large networks or as core switches in relatively smaller networks. Managed switches should support both L2 switching and L3 IP routing, though you’ll find some with only L2 switching support.

Conclusion

The Ethernet switch plays an integral role in most modern Ethernet local area networks (LANs). Mid-to-large sized LANs contain a number of linked managed switches. Small office/home office (SOHO) applications typically use a single unmanaged switch. This article has introduced the different types of switches. Depending on the number of devices you have and the number of people using the network, you have to choose the right kind of switch that fits your space. FS.COM has provided a comprehensive set of Ethernet switches. If you have any requirements, welcome to visit our website for more detailed information.