Once you understand the ways in which routing and switching technologies can help your business, the next step is to determine whether you have the right foundation for your company's needs. The following is a list of considerations to get you started.
The quality of your existing equipment Consumer grade or home networking products can't keep pace with the challenges posed by business growth. For example, these products may not be able to handle the traffic or allow you to add voice or video communications or wireless well and may require you to manage each device individually. Business grade routers and switches provide reliable communications to your company and provide economies via shared equipment. Flexibility Invest in a network that can grow over time so that you can add features and functionality when your company needs them.
Additions might include new applications like video monitoring, IP telephony, integrated messaging and wireless. Easy connectivity Make sure your routing and switching gear is easy to install use, and manage For example, switches with in-line power allow you to place equipment, such as wireless access points and IP phones, anywhere there's a network wall jack. This saves you the trouble and expense of installing extra electrical outlets or wires to power the devices.
Reliability Business crises come in all varieties - from power failures to hurricanes and everything in between. Your organization's ability to maintain normal operations during a crisis may rely on the health of your network. A network designed with reliability and redundancy will provide the reassurance you need that your business will continue.
Contact a Cisco partner to learn more and get exactly what you need. Skip to Main content Skip to Footer. Consider the following: How do you connect to the Internet to watch important presentations? Through your network. Where is your company's software?
On the network. How does an important presentation get shared by multiple members of your team? Via the network. What carries critical messages to your employees and partners? Your network. Though they look quite similar, routers and switches perform very different functions in a network: Switches are used to connect multiple devices on the same network within a building or campus.
For example, a switch can connect your computers, printers and servers, creating a network of shared resources. Our switches are powered by intent and informed by context, with security embedded throughout.
They help your network continuously learn and evolve to meet business needs. Seamlessly integrate with full-stack programmability, from ASIC to the OS, helping you to add future features without upgrading hardware. Find and compare switches by using the Cisco Switch Selector.
View all Cisco switches. Simple, flexible software subscription suites help you achieve the latest Cisco DNA innovations in policy-based automation, secure connectivity, and critical analytics and assurance across your network. Get highly secure, scalable performance and intuitive management with Meraki MS cloud-managed access and aggregation-layer switches.
Confidently move to a secure, automated intent-based network IBN with expert guidance, proven experience, best practices, and innovative tools. Are you a Cisco partner? Log in to see additional resources.
Looking for a solution from a Cisco partner? Connect with our partner ecosystem. Operate your network with simple, flexible, and highly secure solutions specifically designed for the small business. Skip to content Skip to search Skip to footer. Back Next. Data center switches Enterprise switches. The full list of features and functionalities of a network switch will vary depending on the switch manufacturer and any additional software provided, but in general a switch will offer professionals the ability to:.
In larger networks, switches are often used as a way to offload traffic for analytic purposes. This can be important to security, where a switch can be placed in front of a WAN router, before the traffic goes to the LAN. It can facilitate intrusion detection, performance analytics, and firewalling. In many cases, port mirroring is used to create a mirror image of the data flowing through the switch before it is sent to an intrusion detection system or packet sniffer, for example.
At its most basic, however, it is the simple task for a network switch to quickly and efficiently deliver packets from computer A to computer B, whether the computers are located across the hallway or halfway around the world. Several other devices contribute to this delivery along the way, but the switch is an essential part of the networking architecture.
Keith Shaw is a freelance digital journalist who has written about the IT world for more than 20 years. Here are the latest Insider stories.
More Insider Sign Out. Sign In Register. Sign Out Sign In Register. Latest Insider. Check out the latest Insider stories here. More from the IDG Network. Chapter 1: Internet Protocol Operations Fundamentals. At the time of this writing, Cisco designs the Catalyst switches for campus networks and Nexus switches for data centers.
Figure illustrates the current recommended Catalyst switches. However, in the competitive campus switch marketplace, Cisco continuously updates the Catalyst switches with new capabilities, higher performance, higher density, and lower cost.
Figure Cisco Catalyst Switches. Interesting enough, the Catalyst was not detailed in Figure Despite its extremely long life cycle, Cisco marketing has finally shifted focus to the Catalyst For a large number of you reading this book, you have likely come across the Catalyst at some point in your career. Cisco offers two types of network switches: fixed configuration and modular switches.
With fixed configuration switches, you cannot swap or add another module, like you can with a modular switch. In enterprise access layers, you will find fixed configuration switches, like the Cisco Catalyst, X series. It offers a wide range of deployments. In the enterprise distribution layer, you will find either fixed or modular switches depending on campus network requirements.
An example of a modular switch that can be found in the distribution layer is the Cisco Catalyst X series. This series of switches allows you to select different network modules Ethernet or fiber optic and redundant power supply modules. In small businesses without a distribution layer, the X can be found in the core layer. In large enterprise networks, you might find X in the access layer in cases where high redundancy and full Layer 3 functionality at the access layer are requirements.
In the enterprise core layer, you will often find modular switches such as the Cisco Catalyst or the Catalyst series. This individualization allows for customization and high-availability options when necessary. If you have a network where there is a lot of traffic, you have the option to leverage the Cisco Catalyst X series switches into the distribution layer.
All switches within the X, X, X, and X series are managed. This means that you can configure an IP address on the device. An unmanaged switch is only appropriate for a home or very small business environment. It is highly recommended not to use an unmanaged switch in any campus network.
This section just described a few examples of Cisco switches and their placement in the network. These types of switches make decisions about forwarding frames based on the destination MAC addresses found within the frame. Recalling basic networking: A switch collision domain is only port to port because each switch port and its associated end device is its own collision domain.
Because there is no contention on the media, all hosts can operate in full-duplex mode, which means that they can receive and transmit data at the same time. When a switch receives in store-n-forward mode, the frame is checked for errors, and frames with a valid cyclic redundancy check CRC are regenerated and transmitted. Some models of switches, mostly Nexus switches, opt to switch frames based only on reading the Layer 2 information and bypassing the CRC check.
This bypass, referred to as cut-through switching, lowers the latency of the frame transmission as the entire frame is not stored before transmission to another port. Lower switching latency is beneficial for low-latency applications such as algorithm trading programs found in the data center.
The assumption is that the end device network interface card NIC or an upper-level protocol will eventually discard the bad frame. Most Catalyst switches are store-n-forward. To figure out where a frame must be sent, the switch will look up its MAC address table. This information can be told to the switch or it can learn it automatically. The switch listens to incoming frames and checks the source MAC addresses.
The forwarding table is also called the CAM table. What happens if the destination MAC address of the frame is unknown to the switch? The switch then forwards the frame through all ports within a VLAN except the port the frame was received on.
This is known as unknown unicast flooding. Broadcast and multicast traffic is destined for multiple destinations, so it will get flooded by default. Referring to Figure , in the first example, the switch receives a frame on port 1. The destination MAC address for the frame is The switch will look up its forwarding table and figure out that MAC address The switch will then forward the frame through port 5. In the second example, the switch receives a broadcast frame on port 1. The switch will forward the frame through all ports that are within the same VLAN except port 1.
The frame was received on port 1, which is in VLAN 1; therefore, the frame is forwarded through all ports on the switch that belong to VLAN 1 all ports except port 3. When a switch receives a frame, it places the frame into an ingress queue. A port can have multiple ingress queues, and typically these queues are used to service frames differently for example, apply quality of service [QoS].
From a simplified viewpoint, when the switch selects a frame from a queue to transmit, the switches need to answer a few questions:. Decisions about these three questions are answered, respectively, as illustrated in Figure and described in the list that follows. Figure Layer 2 Switch Operation: Mechanics.
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