Dell switches make waves

Dell switches make waves

With miniscule margins on personal computers and servers, it's not surprising that Dell Inc. is branching out with forays into other aspects of the datacenter. What is surprising is that they're doing it very well.

Server and workstation manufacturers have entered the LAN market before; Dell recently moved into this space, aiming squarely for the low-end unmanaged market with their 2000 series unmanaged switches. With some success under its belt, Dell is now setting the bar quite a bit higher with the Dell PowerConnect 3300 series switches.

The 3300 series switches come in a variety of flavors, differentiated by port count. I looked at the Dell PowerConnect 3324 and 3348, 24-port and 48-port 10/100 managed 1U switches including two gigabit ports with both GBIC (Gigabit Interface Converter) slots and copper connectors. Unless you're running a fiber trunk to the switch, no extra GBIC is required. Both units feature redundant power capability with a US$399 Dell redundant power source.

It's hard to get excited about 10/100 switches these days, but the feature/price ratio of these units is impressive. The switches support per-port QoS; layer 3 and layer 4 traffic prioritization; port mirroring; link aggregation; layer 2, 3, and 4 access control lists; SSH/SSL encryption for management sessions; and RADIUS management authentication. To achieve all this and still play nice with others, the 3300 series is heavily invested in standards such as 802.1q VLAN trunking, GVRP VLAN management, spanning tree, and 802.3 link aggregation. Additionally, the 3300 series can stack up to six switches or 192 ports.

The 3300 series comes with a laundry list of features, but some are not yet completely fleshed out. VLAN support is limited to 256 VLANs, there are only four service-class queues, and there are puzzling and frustrating quirks with the Web management interface. Nevertheless, the switches provide lots of functionality for a small price tag.

On the bench

Same as any other switch, configuring a PowerConnect switch starts with a serial console. In Dell's case, the PowerConnect CLI (Command Line Interface) is nearly a dead ringer for Cisco's IOS (Internetwork Operating System). The concepts of user and privileged exec modes are there, as are most IOS reflexes such as command abbreviation, tab completion, syntax help, and hierarchical config mode.

This Cisco-illusion ended when I ran into notable departures from IOS and had to start hunting for commands. For instance, "wr mem," "sh conf," aren't available in the Dell CLI, but "copy run start" and "sh start" work. Interface designations are similar, albeit inverted.

The similarity to IOS will shorten the learning curve for many Cisco-versed network administrators, but there are enough differences to cause some frustration in a mixed environment. Indeed, the Dell CLI Version definitely has some weak points. Administrators used to pasting configurations into the CLIs of other vendors' switches may find that that doesn't work here. When I tried it, the 3300 series couldn't keep up with unbuffered pastes.

The CLI also became unresponsive for several seconds following a 50-line ACL (Access Control List) paste; of the 50 lines pasted, only three were actually processed by the switch. With this kind of delay, large scripted changes could run into problems.

While I worked in the Web interface, the solution again showed rough edges. At one point, any access list creation request returned a general error with no explanation. Later, the application of an ACL to a port returned a cryptic error, "Can't apply input Policy 0 because of HW resources lack." When I added entries to an ACL that had already been removed, the previous ACL priority levels were unavailable. These problems weren't endemic but did reveal some code immaturity. Dell acknowledged these issues and is actively improving and developing the PowerConnect OS.

The raw switching functions of the 3300 series performed well, easily handling the throughput tests with and without ACLs. The interoperability tests were also successful, and 802.1q trunking to a Cisco Catalyst switch was not a problem.

View from the top

Despite the slight problems with CLI and Web management, Dell has an ace up its sleeve: the Dell OpenManage Network Manager. Bundled with every managed switch, Network Manager drives like other Dell management consoles, requiring the OpenManage framework and integrating as a module. For those without an OpenManage server, you'll need a dedicated server, as Network Manager requires significant disk, RAM, and CPU resources for even a single module.

The benefits of this console in an environment of five or more switches are readily apparent. Utilizing SNMP, Network Manager scans the network for Dell devices and populates a database with pertinent information gathered from the switches. From there, switch polling at regular intervals keeps the management system up to date on changes to configurations and network topology.

Within Network Manager, it is possible to compare configurations between a selected group of switches, back up configurations, make individual or grouped configuration changes, view the current network topology with color-coded status icons, and configure traps and alerts for error or warning events. This level of functionality is usually found in network hardware vendors' expensive add-on packages, such as CiscoWorks. Although Network Manager can't compete with CiscoWorks' features, it does have the important functions such as configuration comparison and group configuration changes.

What it lacks is cost. The fact that a tool of Network Manager's scope is included for free with a US$949 48-port Ethernet closet switch is intriguing. It will permit less-skilled administrators to easily configure and maintain the more esoteric aspects of their network without advanced CLI or scripting knowledge, and without busting the budget.

Overall, the 3300 series performed well, albeit with a few frustrating, notable problems. It's clear that Dell needs to work out some kinks in the firmware, but they're definitely heading in the right direction.

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