The 3500 XL switches are available in three configurations: The 3512 XL offers 12 10/100 ports and two Gigabit Ethernet ports; the 3524 XL has 24 10/100 ports and two Gigabit Ethernet ports; and the 3508G XL sports eight Gigabit Ethernet ports. I tested beta versions of each in Network Computing's University of Wisconsin Real-World Labs®, and found that they suit different needs. While the 3512 XL and 3524 XL switches are perfect for aggregating workgroup hubs and switches into a high-speed uplink, the 3508G XL is ideal for aggregating Gigabit Ethernet-capable devices into a single Gigabit Ethernet uplink.
The standard edition of these switches is priced at $2,495, $3,495 and $4,995, respectively. Their enterprise edition counterparts cost an additional $500 each. The add-on GigaStack Stacking GBICs are individually priced at $250.
The 3500 XL boasts simplified, centralized device management with its new clustering technology. One switch in each cluster is designated the "command" switch; the remaining switches serve as "members." The command switch is responsible for configuring member switches. If you cluster a 3500 XL series switch along with older 2900 XL and 1900 switches, you can configure and manage as many as 16 devices from a central location.
The simplicity of this process was amazing. I configured a stack of six different switches--three 3500 XL series switches and three 2900 XL series switches--and used several different stacking options. After connecting the first two switches via GigaStack GBICs, I stacked two additional switches using Gigabit Ethernet links, and connected the remaining three switches via Fast Ethernet over Category 5 cable. Once I configured an IP address on the Catalyst 3508G and designated it as the command switch, I accessed it via the Visual Switch Manager Web interface. Next, I ran the switch's Java-based Cluster Builder application to add all the switches to the new cluster. This software located all the other cluster-capable switches, so I proceeded to build a cluster of the remaining switches. Then I was able to manage all configuration options via the command switch and its Web interface.
This Web-based management interface offers other management tools that can simplify your life. With the ability to build simple network maps, the Virtual Switch Manager interface gives you a quick view of your network topology. And the Network View Java applet displays the other devices on the network.
Upgrading switch software also has become less of a chore. Enhancements to the Web interface let you upgrade software on all your switches from the central point of management of your command switch. If you're in love with the Cisco IOS (Internetwork Operating System) command line, don't fear--you can still make all these configuration changes from a terminal session.
The 3500 XL series supports management features analogous to the 2900 XL series. In-band management can be achieved via SNMP or telnet, and the switch supports four groups of RMON: History, Statistics, Alarms and Events. Unfortunately, as of press time, the command switch was not capable of collecting SNMP and RMON information from its member switches. If you need to retrieve these statistics, you must individually assign IP addresses to member switches. This task goes against the grain of what Cisco is trying to accomplish with centralized management; however, the company says it plans to address this issue in future software versions.
I benchmarked the 3500 XL's performance with a Netcom SmartBits SMB-2000 performance analyzer and discovered that these new switches are fast, but not completely wire-speed. Initially, I performed my testing on the 3524 XL with a dozen 100-Mbps half-duplex traffic streams. It only forwarded about 94 percent of network traffic in a wire-speed stream of 64-byte packets. However, for packet sizes of 128 bytes or greater, the product was able to switch packets at wire-speed. Likewise, when I added one gigabit stream between the switch's two Gigabit Ethernet ports, 128-byte packets degraded to 97 percent, but 256-byte and greater packets were switched at wire-speed. This performance is sufficient for most networks.
Something for Everyone
With the 3500 XL series, Cisco also introduces the GigaStack Stacking GBIC. This two-port module is designed to enhance the switch's stacking capabilities without the need for a costly standard GBIC. It also lets you conserve valuable gigabit ports, providing two ports per GigaStack module. Up to nine switches can be stacked with GigaStack GBICs, which use a copper cable similar to FireWire for short-distance stacking. The mode of communication with the GigaStack module depends on how you deploy it. If only one port of the module is used on both ends of the connection, the communication will be full-duplex. If both ports are used on either end, communication will fall back to half-duplex.
Comparable to the Catalyst 2900 XL series, the 3500 XLs are available in two software versions: standard and enterprise. The standard edition software includes EtherChannel and port-based VLAN features, while an upgrade to the enterprise edition delivers
ISL (Inter-Switch Links) and 802.1q VLAN support, VLAN Trunking Protocol and Spanning Tree Uplink Fast ability, as well as TACACS+ support. Software upgrades transform the 2900 XL Series into either a command switch or a member switch; a 1900 Series device can only become a member switch.
Mark Degner is a consultant for Greenwich Group Solutions in Chicago. Send your comments on this article to him at mdegner@nwc.com.
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