Cisco catalyst switch types, fixed configuration & chassis based model

Cisco Catalyst Switch Family Album The Cisco Catalyst switch family represents one of the most popular LAN switches on the market today. The Catalyst range is designed to meet the needs of a wide range of customers—from small to medium businesses, right up to large enterprise networks and service providers. Cisco Catalyst switches provide high performance, scalability, manageability, and many other intelligent features that ensure their success to date.

We can find that Cisco Catalyst switches present one of more difficult product sets to work with, simply because of the large range of switch families available, the vast differences in features between low-end and high-end platforms, and the different operating systems used. When you select a switch platform and model to use to build a LAN network, you must bear in mind that these differences exist; otherwise, you might purchase one or more switches that don't quite do the job you expected.

Cisco Catalyst switches can physically described by one of two device types: • Fixed-configuration switch • Chassis-based switch The fixed-configuration switch consists of a fixed number or ports contained within a fixed chassis that includes an internal switch processor.

Some of these devices provide a limited degree of modularity in that they include modular slots that can be populated by variety of different modules.

The major advantages of fixed-configuration switches are low cost and ease of deployment. The major disadvantages of a fixed-configuration switch are a lack of flexibility and the introduction of a multiple management points in the network when installing more than one switch. Scaling the network by introducing multiple fixed-configuration switches can also introduce bottlenecks between each switch.

NOTE Some Catalyst switches support stacking¸ where a group of Catalyst switches can be managed as a single entity. Traditionally, the Catalyst 2960 and Cisco 3560 switches have supported stacking; however, inter-switch performance is limited for larger stacks and the ability to manage the stack as a single entity has had some restrictions. The recent Catalyst 3750 series of switches now include stacking technology that includes a high-speed 32 Gbps backplane and also allows the stack to be completely managed as a single switch.

The chassis-based switch provides a chassis as a starting point, after which you can add the various components of the switch as you require. You

can determine a particular type of switch processor and switching module, and then install these options. Chassis-based switches provide slots, which support various types of modules. The major advantages of chassis-based switches include high performance, flexibility, simplified management, and extended product lifetime. Chassis-based switches also commonly offer redundancy features to ensure the failure of a module, power supply, or other component does not cause a network outage. The major disadvantage of chassis-based switches is the high cost involved.

Indicates the various models that comprise the Cisco Catalyst switch family--- Table 1-1 Model

Format

Status

Catalyst 1900/2800

Fixed Configuration 10BASE-T + 100BASE-T Uplinks

End of Sale Recommended replacement = Catalyst 2950

Catalyst 2900XL/3500XL

Fixed Configuration 10/100BASE-T + Uplinks

End of Sale 1000BASE-X Recommended replacement = Catalyst 2950/3550

Catalyst 2900G

Fixed Configuration 10/100BASE-T + Uplinks

Legacy 1000BASE-X Recommended replacement = Catalyst 2950/3550

Catalyst 2950

Fixed Configuration Current 10/100BASE-T + 1000BASE-X Uplinks

Catalyst 3550

Fixed Configuration Current 10/100BASE-T + 1000BASE-X Uplinks

Catalyst 3750

Fixed Configuration 10/100/1000BASE-T 1000BASE-X Uplinks

Catalyst 4000/4500

Chassis

Current +

Current

Model

Format

Status

Catalyst 4900

Fixed Configuration (n x 1000BASE-X)

Legacy Recommended replacement = Catalyst 3550/3750

Catalyst 5000/5500

Chassis

Legacy Recommended replacement = Catalyst 6000/6500

Catalyst 6000/6500

Chassis

Current

Catalyst 8000/8500

Chassis

Current

Each of the Catalyst product families are listed above, with the form factor and current status of each switch indicated. Each of the product families in bold are considered current products and are recommended for deployment for new networks or for network upgrades. All other product families are either end of sale or considered legacy products that should be purchased only for existing networks where a common platform needs to be maintained.

Each of the switches in Table 1-1 is targeted at a particular switching environment, based upon size, network traffic, and features required. One way of classifying the general role of a switch is to identify the hierarchical layer in which the switch is operating.

Well-designed LAN networks can be divided into three key layers: • Access— Provides access to the network for end devices, such as user PCs, servers, and printers.

• Distribution— Provides an aggregation point for access-layer devices and then connects directly to the core. Layer 3 switching can be applied at this point, which improves convergence and scalability and allows for the introduction of network policies.

• Core— Central portion of the network that interconnects all distribution layer devices. The core is normally redundant and highspeed. The main job of the core is to switch traffic as fast as possible, due to the high volumes of traffic within the core. The core layer can either be a Layer 2 only core or a Layer 3 core that relies on routing for

redundancy and convergence.

For many networks, a network switch can provide the functions of two layers or even the entire three. Only the very large networks typically have distinct core, distribution, and access layers; smaller networks typically have a combined core/distribution layer and an access layer.

Following the core/distribution/access layer design provides a hierarchical network that can easily scale as the network grows. Figure 1-1 illustrates the various layers of a LAN network and which platforms fit into each of the layers.

Figure 1-1 Core/Distribution/Access Layers In Figure 1-1, notice that all of the Catalyst switches (bar the Catalyst 8500) can be used as an access layer switch. Most commonly, the access layer function is left to the switches up to the Catalyst 4000/4500 series; however, many larger networks use the Catalyst 5000/5500 and Catalyst 6000/6500 switch as a wiring closet switches, because they can provide very high port densities. When this happens, the high-end switch is normally providing distribution layer functionality as well.

Cisco Catalyst Switch Platforms Although Cisco Catalyst switch platforms are available, each of which are suitable for different switching environments depending on the size, complexity, features required and of course cost. In this section, each of the Cisco Catalyst switch platforms that are available for purchase and not considered legacy switches are described (i.e., the platforms highlighted bold in Table 1-1). This includes the following switch platforms: • Catalyst 2950/3550 family • Catalyst 3550/3750 • Catalyst 4000/4500 • Catalyst 6000/6500

NOTE The Catalyst 8500 switch is not discussed in this section because the Catalyst 6000/6500 switches now outperform this switch.