Networking

Select the right workgroup switch for the job: A case study

When redesigning a network, it's crucial to select equipment that meets your company's needs and matches its budget. Scott Lowe explains how he compared replacement workgroup switches for one company and decided to use the HP 4108GL.


I was recently tasked with replacing the network gear for a small, 40-person office. Prior to replacing the equipment, the office was running on a single 12-port 3Com switch and three 3Com 10/100 hubs, each connected to a port on the switch. The servers in the office were connected to one of the hubs. Here I will detail how I compared possible switches and came to a conclusion that met this company's needs for connectivity and expansion within an affordable budget.

Why the change?
After experiencing a number of network-related problems (e.g., slow network activity, trouble accessing the servers and the Internet, lack of management capability, no way to determine network load levels, and no easy way to do a simple upgrade), the organization realized that it was time to do something. Since none of the equipment was manageable, there was no easy way for me to monitor the entire network's traffic to determine its exact load. Because of this, I decided to look for equipment that was capable of handling a larger load than necessary.

The requirements for the final project were to have:
  • Enough ports for all users, plus extra for new employees to be added.
  • Enough capacity to handle adding employees.
  • Gigabit connectivity for at least two of the servers, with an option for more gigabit ports if necessary.
  • A budget that the company could afford.

The vendors
In proposing a solution for this organization, I decided that a modular chassis-based solution would best serve its needs. In the future, this company will likely need to include additional gigabit Ethernet ports and possibly more 10/100 Ethernet ports. Although I could have easily chosen a fixed form factor, stackable solution, those tend to limit the available options. For example, many 24-port 10/100 switches come with one or two gigabit Ethernet ports. However, if I need to add an additional gigabit port, the company would need to purchase an additional 24-port switch, which may prove too costly. Using the chassis-based solution allows an organization to add only what it needs, within the confines of the available modules, while staying on budget.

In this scenario, I compared units from 3Com (the Switch 4007), Cisco (the Catalyst 4000 series, which includes the 4006), and Hewlett-Packard (the Procurve Switch 4108GL and Procurve Switch 4000m).

In Table A, you'll find a summary of each unit's features. For the average street price (the going rate), I have priced out the chassis and included separate pricing for a switch fabric or management engine and average prices per 10/100 and 1000 port. Note that all pricing assumes only Layer 2 functionality.

Switch fabric and management engine
A switch fabric provides the physical interconnection that directs traffic from one switch port to another switch port. A management engine is generally an additional module that acts as a central collection point for network traffic statistics in the chassis.

Table A
Vendor 3Com Cisco HP HP
Model 4007 4006 4018GL 4000m
Layer 2 or Layer 3 Either Either Layer 2 Layer 2
Number slots (payload) 6 5 8 10
Max 10/100 ports/blade 36 48 24 8
Max 1000 ports/blade 9 48 6 1
Max 10/100 ports (chassis) 216 240 192 80
Max 1000 ports (chassis) 54 240 192 80
Throughput (Mbps) 80.3 48 71.4 4.67
Switching bandwidth (Gbps) 48 64 36.6 3.8
Warranty 1 year 90 days Life Life
Average street price $2,800 $8,200 $3,100 $1,200
Switch fabric or engine $5,800 $6,000 Included Included
Cost per 10/100 port $111 $70 $55 $50
Cost per Gb port $700 $160 $235 $400

Looking at the chart, you can see that each equipment's capabilities vary widely. I quickly dismissed the HP Procurve 4000m due to its limited expansion possibilities, throughput speed, and switching bandwidth.

Backplane speed change
When I originally compared the Catalyst 4006, the maximum backplane speed was 32 Gbps rather than 64 Gbps.

This left the 3Com 4007, the Cisco Catalyst 4006, and the HP 4108GL units. The 3Com unit met most of the criteria listed except the major one: cost. I quickly determined that the 3Com unit was too expensive; with costs from Cisco and HP ranging from $50 to $70 per 10/100 port, $111 was just too much.

Only serious inquiries may apply
I had narrowed the search down to the Cisco Catalyst 4006 and the HP Procurve 4108GL. After comparing these two units, I chose the HP over the Cisco for a number of reasons. The first reason was the price. The HP unit, with 72-10/100 ports and three 100/1000T ports came in at under $7,000 (which was a much lower per-port cost than the other compared switches). In addition, a 24-port fixed form factor 10/100 switch was included for free, which I used in this setup.

Also, at the time I proposed this solution, the HP unit was rated faster than the Cisco in both packets processed per second and switching backplane speed. But Cisco has recently upgraded the speed of the Catalyst 4006, and it can now support speeds up to 64 Gbps, which is faster than its previous incarnations (at 32 Gbps) and faster then the 36.6 Gbps in the HP Procurve 4018GL units. Before purchasing the more costly Cisco unit, carefully consider your organization's needs. You shouldn't base such a purchasing decision on speed alone.

Another significant consideration when making my choice was warranty. Most HP networking equipment carries a lifetime warranty. While some vendors define lifetime as the life of the product line, HP defines it as the time the customer actually owns the equipment. For years to come, this organization will not have to worry about replacing this equipment (at their expense), even if it fails five or six years down the line. Of course, the organization may need to upgrade by then, but that's a different story.

One drawback you may need to consider when comparing these HP and Cisco units is the lack of Layer 3 functionality in the HP units. The HP 4108GL doesn't offer Layer 3 switching functionality, but the Cisco 4006 does. For this article, however, I only compared the Layer 2 functionality, because this organization had no need for Layer 3 switching capability. The group is using a Cisco PIX firewall and Cisco 1720 router to connect to the Internet, so there is no substantial routing happening. In addition, while the Cisco unit offers the potential for more ports in the single chassis, the chances of this group growing that much are quite remote. However, if the company did need Layer 3 switching, I wouldn't have chosen this particular HP switch. I may have instead considered the HP 9300 series routing switches.

Final comparisons
When comparing Layer 2 statistics between the two finalists, I looked at more than just the raw specifications on the vendor’s Web sites. I like to make sure I do due diligence when choosing gear for any organization. So I looked for reviews and also visited The Tolly Group Web site to see if it had done any work with these units. They had. In fact, in December 2001, The Tolly Group produced a report comparing the Cisco Catalyst 4006 switch to the HP Procurve 4108GL. In its tests, the group determined that the HP switch was able to deliver 100 percent of its theoretical maximum throughput for all frame sizes across gigabit modules. In addition, the HP unit was able to deliver 80 percent more zero-loss packets at varying frame sizes than the Cisco unit. The full report comparing the two switches is available for $99 on The Tolly Group site.

One final plus on the HP side is in the area of management features. The ability to handle remote monitoring makes the HP Procurve a stronger choice. The HP 4108GL supports SNMP statistics as well as four groups of RMON. The RMON groups supported are statistics, history, alarm, and events.

RMON
RMON is used for remote monitoring of a network switch. With RMON, network statistics are gathered at a single workstation. SNMP defines specific information using a single management information base (MIB), while RMON provides support for up to nine more categories of information. It is up to each vendor to implement RMON and to determine which RMON levels they will support.

Out of the box and into the fire
I've worked with Cisco, 3Com, Bay Networks/Nortel, and many other types of equipment, but with HP, I had only worked with the lower-end HP Procurve 4000 series switches. I must admit I was quite impressed when I opened the box. For a very good price, the 4108GL is a well-built package with diagnostic LEDs that make sense, and its management capability is very good. Every port supports autosensing MDI/MDI-X so that any cable—crossover or not—works on any port, regardless of what's connected to this other end. This unit can be managed via Web, Telnet, console, SNMP, and RMON or by the included HP Toptools software.

The installation of the 4108GL was a piece of cake. Before I actually installed it, I assigned an IP address and name (using the serial port interface) to it and let it run for a couple of days with only a single network link attached to make sure I had it up and running properly. When I finally installed it, I removed the old switch and hub stack and connected the patch cables from the patch panel to ports on the HP 4108GL. I was done in less than a half an hour, and the staff noticed an immediate improvement in all areas of network activity. Files were retrieved faster from the server, and e-mail downloaded with less lag time.

An outstanding choice
While price was a major factor in this decision, I am both pleased and comfortable with the choice I made in the HP Procurve 4108GL switch. Currently, the switch is at half of its physical capacity, so there is plenty of room to grow. Also, individual port traffic is very low—currently it's at less than 5 percent on every port with very few peaks going no higher than 10 percent utilization. This switch will be able to serve the organization for a number of years, especially considering the inclusion of a lifetime warranty. With 72 10/100 ports and three 1000BaseT ports for under $7,000, this was an excellent investment.

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