Appendix E: Switch Features

This appendix is dedicated to helping you determine which switch needs to be placed in your network. If the wrong switch is placed in each point in your network the load can cause severe problems, including bottlenecks or load failures. We will break down the switches into the layers in which Cisco feels they should reside, based on their latest certification curriculum.

Access Layer Switches

The Access layer is the access point where the workgroup layer or end−user interface enters the network. This layer provides the means to connect to the devices located in the Distribution layer and provide connections to both local and remote devices. The goals of this layer are to pass traffic to the network for valid network users and to filter traffic that is passed along. Because the Access layer is the entry point to the network, only port security−based decisions, such as those based on the Layer 2 hardware addresses, can be made here.

Devices found at this layer and covered in this chapter are as follows:

∙Cisco Catalyst 1900 series

∙Cisco Catalyst 2820 series

∙Cisco Catalyst 2900G series, including the new 2980G series

∙Cisco Catalyst 2900 XL series

∙Cisco Catalyst 3000 series

∙Cisco Catalyst 3500 XL series

∙Cisco Catalyst 3900 series

Cisco Catalyst 1900

The Catalyst 1900 is the entry point for Cisco’s switch line. There are two types of Catalyst 1900 switches: the Standard Edition (SE) and the Enterprise Edition (EN).

The Standard Edition, as explained in Chapter 15, is a low−cost alternative for administrators migrating from a shared hub environment or smaller scale installations. The SE uses a menu−driven IOS and cannot handle some of the more advanced features available in the Enterprise Edition of the IOS.

The Enterprise Edition contains all the features of the Standard Edition but provides several high−end solutions, including Fast EtherChannel, support for Inter−Switch Link (ISL), an IOS Command Line Interface (CLI), and support for Cisco Group Management Protocol (CGMP).

The 1900 series offers two different models: the Cisco Catalyst 1912 and the Cisco Catalyst 1924. They are identified by the number of standard ports. Table E.1 shows the features of each switch.

Table E.1: Features available for the Cisco Catalyst 1912 and Catalyst 1924.

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Cisco Catalyst 2820

For an environment that needs high−speed links to the wiring closet for 20 or so users, the Catalyst 2820 is an ideal solution. This switch is perfect for smaller wiring closets where it is not economical to purchase a high−end solution such as a Cisco Catalyst 5000 series switch.

The Catalyst 2820 series switch architecture is virtually identical to that of the Cisco Catalyst 1900 series switches, differing mainly in its height and uplink bays. The switch has two uplink bays that allow for high−speed uplink options such as Fiber Distributed Data Interface (FDDI), Copper Distributed Data Interface (CDDI), 100Mbps, and Asynchronous Transfer Mode (ATM) modules.

The 2820 series comes in two models: the Cisco Catalyst 2822 and the Cisco Catalyst 2828. On both switches, you will find twenty−four 10BaseT Ethernet ports and one 10Mbps attachment unit interface (AUI) port. All the features listed earlier for the Catalyst 1924 apply to the Catalyst 2822 and the Catalyst 2828, as shown in Table E.2, with the exception of the number of allowable MAC addresses.

Table E.2: Features available for the Cisco Catalyst 2822 and Catalyst 2828.

Cisco Catalyst 2900

Two quite significantly different architectures are found in the 2900 series of switches: the 2900 series switches and the XL version of the 2900 series switches. About the only similarity between these series is their low cost; if you compare the Catalyst 2900 family of switches’ performance and features to other Cisco Catalyst switches, this series is one of the best values for your money.

The 2900 series includes the 2901, 2902, 2926, and 2948G. These switches use an architecture similar to that of the Cisco Catalyst 5000 series of switches. This series uses the Set/Clear command−based CLI, allowing the switch to support advanced features such as ISL.

The XL series was introduced long after Cisco released its prized Catalyst 5000 series of switches, and it causes great confusion to customers of Cisco resellers because the 2900 XL series has a lower model number. In most cases, vendors assign higher model numbers to newer, better, and faster models. One of the most noticeable differences between the 2900 XL series and the 5000 series, which uses a Set/Clear CLI, is that the XL series uses the true Cisco IOS, which is almost identical to that of Cisco routers. The 2900 XL series is the wiring closet workhorse for 10/100 auto−negotiation. Auto−negotiation allows the switch to negotiate the switch port speed and duplex based on the type of traffic being sent to the switch by the sending interface. The models available in this series are the 2908 XL, 2912 XL, 2916 XL, and the 2924 XL.

The 2900 XL series supports some comprehensive management features including a built−in Hypertext Transfer Protocol (HTTP) server for the Web−based Cisco Visual Switch Manager, Simple Network Management Protocol (SNMP), Cisco Discovery Protocol (CDP), CiscoWorks for Switched Internetworks (CWSI), and embedded agent support for four groups of Remote Monitoring (RMON).

Its security and redundancy features support user−selectable port security, multilevel console security, Cisco IOS IP access lists, Terminal Access Controller Access Control System Plus (TACACS+) authentication, and IEEE 802.1D spanning−tree support. Take a look at Table E.3 to see the hardware features of each switch.

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Table E.3: The models and features available for the standard version of each Cisco Catalyst 2900 XL series switch.

The Cisco Catalyst 2926 and the 2948G are both similar to the architecture of the Cisco Catalyst 5000 series. These switches are store−and−forward mode switches with many high−end features:

∙A high−performance 24Gbps non−blocking architecture switching fabric capable of delivering over 1 million packets per second (pps).

∙The capability for users to configure each port with priority levels to accommodate time−sensitive applications such as voice and video.

∙Support of Fast EtherChannel (FEC) uplink bundles for up to 400Mbps on the Catalyst 2926T and 2926F. The Catalyst 2926GS and 2926GL each support uplinks of up to 800Mbps. These FEC ports can be configured between two switches, two routers, or a switch and a router. Special configurations and Network Interface Cards (NICs) also allow a server to be configured with FEC uplinks to a router or switch. This ability results in a very efficient high−speed backbone and data center uplinks with automatic load balancing and failover for port failures.

∙Support for RMON statistics, which give a good picture of network activity in the form of statistics, history, events, and alarms groups.

∙Support for VLAN load−balancing and Spanning−Tree on multiple parallel Fast Ethernet ISL trunks to increase capacity and fault tolerance between switches.

∙Support for ISL, Dynamic Inter−Switch Link (DISL), CDP, VLAN Trunk Protocol (VTP), VLAN Membership Policy Server (VMPS), Dynamic VLANs, and port security based on the MAC address.

∙Support for complete SNMP management for Ethernet Management Information Base (MIB), bridge MIB, MIB II, and VTP.

∙Support for management with CWSI, CiscoView, TrafficDirector, and VlanDirector.

∙The 2948G supports advanced scalability for Fast EtherChannel, Dynamic VLANs, and 802.1Q trunking and bandwidth control using Quality of Service (QoS) features such as protocol filtering, link load balancing, per−port security, TACACS+ authentication, and IP permit lists.

The hardware features available for the Cisco Catalyst 2900 series switches are listed in Table E.4.

Table E.4: The models and features available for the standard version of the Cisco Catalyst 2926, 2948G, and 2980G switches.

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Cisco Catalyst 3000

The Cisco Catalyst 3000 has a completely different architecture than any other Cisco switch. However, this series of switches received an End−of−Life (EOL) notice from Cisco, so we will include only a basic overview in this chapter.

∙The Catalyst 3000 series provides the following features:

∙Stacked switch platforms that are manageable as if they were a single logical entity. These switches automatically configure themselves as new switches are added or removed.

∙Cut−through switching technology delivering wire−speed, low−latency switching. The Catalyst 3000 also has the ability to use FragmentFree or Runtless switching, which automatically changes to store−and−forward when an error rate has been exceeded.

∙Optional modules to provide additional interfaces for more Ethernet ports, Fast Ethernet ports, ATM ports, and WAN connectivity.

∙User definable per−port and secure−mode filtering that provides access control for sensitive information resources.

∙Support for up to 64 VLANs using Cisco’s LAN Emulation (LANE)−based ATM, and ISL−based Fast Ethernet VLANs to extend switched VLANs throughout the enterprise.

∙Spanning−Tree Protocol (STP) implemented by VLAN for loop detection.

∙An optional stack port interface module that connects one 3000 series switch to another. This Catalyst Matrix delivers 280Mbps per switch of bandwidth for unrestricted traffic flow.

Some of the basic hardware features of the Cisco Catalyst 3000 series of switches are listed in Table E.5.

Table E.5: The key features of the Cisco Catalyst 3000 series switches.

Cisco Catalyst 3500 Series XL

The Cisco Systems Catalyst 3500 series XL is a scalable line of stackable 10/100 and Gigabit Ethernet switches. These switches provide high performance and investment protection for companies that are expanding their switched networks. The three major applications for the 3500 series XL are as follows:

∙In the enterprise wiring closet at the enterprise edge, aggregated to a larger Catalyst switch

∙In a branch office where it can provide a LAN backbone and desktop connectivity

∙In a multilayer network where it can be deployed with a Layer 3 switch for a low cost solution

Each Catalyst 3500 XL comes with 2 Gigabit Ethernet interfaces that come with 12, 24, or 48 Gigabit Interface Converter (GBIC) ports and auto−sensing 10BaseT/100BaseTX ports. The 3508G XL provides eight

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