Switch Types | How to Select Switch for your network

Switch Types | How to Select Switch for your Network

For designing a switch network the appropriate hardware features of the switch types are considered to support the requirements of your networks. This post will help you How to Select Switch for your network. When designing a network, it is important to select the appropriate hardware to meet the current requirements of the network, as well as to allow its growth. Within an enterprise network, both switches and routers play a very important role in network communication.If you want to learn how to choose a router for your network visit here.

Switch Categories

There are five categories of switches for business networks, which are shown in figure:

• Campus LAN switches : to scale network performance on an enterprise LAN, core, distribution, access and compact switches can be used. These switch platforms vary from fanless switches with eight fixed ports to 13-blade switches that support hundreds of ports. Campus LAN switch platforms include Cisco 2960, 3560, 3750, 3850, 4500, 6500 and 6800 series switches.
• Managed switches in the cloud : Access switches managed through the Cisco Meraki cloud allow virtual stacking of switches. These control and configure thousands of switch ports on the Web, without the intervention of the IT staff.
• Data center switches : data centers must be assembled based on switches that promote infrastructure scalability, continuity of operation and transport flexibility. The data center switch platforms include the Cisco Nexus and Cisco Catalyst 6500 series switches.
• Service provider switches: these switches are divided into two categories, aggregation switches and Ethernet access switches. Aggregation switches are service level Ethernet switches that add traffic to the perimeter of the network. The Ethernet access switches of service providers have application intelligence, unified services, virtualization, integrated security and simplified administration.
• Virtual networks : networks become increasingly virtual. Cisco Nexus virtual network switch platforms provide secure multi-tenant services by incorporating virtualization intelligence technology into the data center network.

Form factors

When selecting switches, network administrators must determine their form factors. This includes the features of fixed configuration (Left), modular configuration (Center), stackable (Right) and non-stackable. The thickness of the switch, which is expressed in the number of rack units, is also important in the case of switches that are mounted in a rack. For example, fixed configuration switches are all units of a rack (1U).

• Cost : the cost of a switch depends on the quantity and speed of the interfaces, the supported functions and the expandability.
• Port density : network switches must support an adequate number of devices on the network.
• Power : Today, it is common to power access points, IP phones and even compact switches using Ethernet power. Some rack-based switches support redundant power supplies.
• Reliability : the switch must provide continuous access to the network.
• Port speed: the speed of the network connection is one of the fundamental aspects for end users.
• Frame buffers : the ability of the switch to store frames is important in networks where there may be congested ports connected to servers or other areas of the network.
• Scalability : in general, the number of users in a network increases over time; therefore, the switch must provide the possibility of growth.

Density of Switch ports

The port density of a switch refers to the number of ports available on a single switch . The illustration shows the port density of three different switches.

• Fixed configuration switches generally support up to 48 ports on a single device. They feature options for up to four additional ports for small pluggable form factor (SFP) devices. High port densities allow better use of limited space and energy.

If there are two switches of 24 ports each, they could support up to 46 devices, since at least one of the ports of each switch is lost in the connection of each switch to the rest of the network. In addition, two power sockets are required.
On the other hand, if there is a single 48-port switch, 47 devices can be supported; In this case, a single port is used to connect the switch to the rest of the network and a single outlet to support the switch.

• Modular switches can support high port densities by adding several switch port line cards. For example, some Catalyst 6500 switches can support more than 1000 switch ports.

Large business networks that support many thousands of network devices require high density modular switches to achieve the best use of space and energy. Without the use of a high density modular switch, the network would need many fixed configuration switches to include the number of devices that need access to the network. This approach can consume many electrical outlets and a lot of closet space.

Switch Forwarding speeds

Forwarding rates define the processing capabilities of a switch by estimating the amount of data the switch can process per second.
Switch product lines are classified according to forwarding speeds. Basic switches have lower forwarding speeds than business-level switches. It is important to consider forwarding speeds when a switch is selected.

If the speed is too low, it cannot include full cable speed communication through all of its switch ports. Cable speed is the data rate that each Ethernet port can obtain on the switch. Data rates can be 100 Mb / s, 1 Gb / s, 10 Gb / s or 100 Gb / s .

Power over Ethernet

Power over Ethernet ( PoE ) allows a switch to supply power to a device through existing Ethernet wiring. This feature can be used in IP phones and some wireless access points.
PoE provides greater flexibility when installing wireless access points and IP phones, allowing them to be installed anywhere with an Ethernet cable. The network administrator must ensure that PoE features are required, because switches that support PoE are expensive.
The relatively new compact Cisco switches of the Catalyst 2960-C and 3560-C series support passage through PoE. The passage through PoE allows the network administrator to power the PoE devices connected to the switch, as well as to the switch itself, by means of energy obtained from certain ascending switches.

Multilayer Switching

Generally, multilayer switches are implemented in the core and distribution layers of an organization's switched network. Multilayer switches are characterized by the ability to create a routing table , by admitting some routing protocols and by forwarding IP packets at a rate similar to layer 2 forwarding. Multilayer switches usually support specialized hardware, such as circuits Integrated application specific (ASIC). ASICs, together with dedicated software data structures, can simplify the forwarding of IP packets independently of the CPU.
In the field of network technology, there is a tendency towards a purely Layer 3 switched environment. When switches were used in networks, none of them supported routing. Today, almost all switches do. It is likely that all switches will soon incorporate a route processor, since the cost of doing so is less and less in relation to other limitations. Finally, the term "multilayer switch" will be redundant.