Cisco Catalyst Switch Family AlbumThe Cisco Catalyst switch family represents one of the most popular LANswitches on the market today. The Catalyst range is designed to meet theneeds of a wide range of customers—from small to medium businesses, rightup to large enterprise networks and service providers. Cisco Catalystswitchesprovide high performance, scalability, manageability, and many otherintelligent features that ensure their success to date.We can find that Cisco Catalyst switches present one of more difficult productsets 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, andthe different operating systems used. When you select a switch platform andmodel to use to build a LAN network, you must bear in mind that thesedifferences exist; otherwise, you might purchase one or more switches thatdont quite do the job you expected.Cisco Catalyst switches can physically described by one of two device types: Fixed-configuration switch Chassis-based switchThe fixed-configuration switch consists of a fixed number or portscontained within a fixed chassis that includes an internal switch processor.Some of these devices provide a limited degree of modularity in that theyinclude modular slots that can be populated by variety of different modules.The major advantages of fixed-configuration switches are low cost and ease ofdeployment. The major disadvantages of a fixed-configuration switch are a lackof flexibility and the introduction of a multiple management points in thenetwork when installing more than one switch. Scaling the network byintroducing multiple fixed-configuration switches can also introduce bottlenecksbetween each switch.NOTESome Catalyst switches support stacking¸ where a group of Catalyst switchescan be managed as a single entity. Traditionally, the Catalyst 2960 and Cisco3560 switches have supported stacking; however, inter-switch performance islimited for larger stacks and the ability to manage the stack as a single entityhas had some restrictions. The recent Catalyst 3750 series of switches nowinclude stacking technology that includes a high-speed 32 Gbps backplane andalso allows the stack to be completely managed as a single switch.The chassis-based switch provides a chassis as a starting point, after whichyou can add the various components of the switch as you require. You candetermine a particular type of switch processor and switching module, and then
install these options. Chassis-based switches provide slots, which supportvarious types of modules. The major advantages of chassis-based switchesinclude high performance, flexibility, simplified management, and extendedproduct lifetime. Chassis-based switches also commonly offer redundancyfeatures to ensure the failure of a module, power supply, or other componentdoes not cause a network outage. The major disadvantage of chassis-basedswitches is the high cost involved.Indicates the various models that comprise the Cisco Catalyst switchfamily---Table 1-1Model Format Status End of SaleCatalyst Fixed Configuration Recommended1900/2800 10BASE-T + 100BASE-T Uplinks replacement = Catalyst 2950 End of Sale Fixed ConfigurationCatalyst Recommended 10/100BASE-T + 1000BASE-X2900XL/3500XL replacement = Catalyst Uplinks 2950/3550 Legacy Fixed Configuration RecommendedCatalyst 2900G 10/100BASE-T + 1000BASE-X replacement = Catalyst Uplinks 2950/3550 Fixed ConfigurationCatalyst 2950 10/100BASE-T + 1000BASE-X Current Uplinks Fixed ConfigurationCatalyst 3550 10/100BASE-T + 1000BASE-X Current Uplinks Fixed ConfigurationCatalyst 3750 10/100/1000BASE-T + Current 1000BASE-X UplinksCatalyst Chassis Current4000/4500 Legacy Fixed Configuration RecommendedCatalyst 4900 (n x 1000BASE-X) replacement = Catalyst 3550/3750 LegacyCatalyst Recommended Chassis5000/5500 replacement = Catalyst 6000/6500
Model Format StatusCatalyst Chassis Current6000/6500Catalyst Chassis Current8000/8500Each of the Catalyst product families are listed above, with the form factor andcurrent status of each switch indicated. Each of the product families in bold areconsidered current products and are recommended for deployment for newnetworks or for network upgrades. All other product families are either end ofsale or considered legacy products that should be purchased only for existingnetworks where a common platform needs to be maintained.Each of the switches in Table 1-1 is targeted at a particular switchingenvironment, based upon size, network traffic, and features required. One wayof classifying the general role of a switch is to identify the hierarchical layer inwhich 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 high-speed. 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 oreven the entire three. Only the very large networks typically have distinct core,distribution, and access layers; smaller networks typically have a combinedcore/distribution layer and an access layer.Following the core/distribution/access layer design provides a hierarchicalnetwork that can easily scale as the network grows. Figure 1-1 illustrates thevarious layers of a LAN network and which platforms fit into each of the layers.
Figure 1-1 Core/Distribution/Access LayersIn 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 layerfunction is left to the switches up to the Catalyst 4000/4500 series; however,many larger networks use the Catalyst 5000/5500 and Catalyst 6000/6500switch as a wiring closet switches, because they can provide very high portdensities. When this happens, the high-end switch is normally providingdistribution layer functionality as well.Cisco Catalyst Switch PlatformsAlthough Cisco Catalyst switch platforms are available, each of which aresuitable for different switching environments depending on the size, complexity,features required and of course cost. In this section, each of the Cisco Catalystswitch platforms that are available for purchase and not considered legacyswitches are described (i.e., the platforms highlighted bold in Table 1-1). Thisincludes the following switch platforms: Catalyst 2950/3550 family Catalyst 3550/3750 Catalyst 4000/4500 Catalyst 6000/6500NOTEThe Catalyst 8500 switch is not discussed in this section because theCatalyst 6000/6500 switches now outperform this switch.