Case Study: 3Com network interface card

The dream of most IT managers is an intelligent network that will alert them to problems before they happen. The lack of...

The dream of most IT managers is an intelligent network that will alert them to problems before they happen. The lack of intelligence in Ethernet cards has thwarted these attempts, until now, thanks to 3Com’s latest NIC cards

3Com dRMON technology helps Reuters' IS staff stay in the know

The news never stops at Reuters America (Stamford, Connecticut), one of the oldest financial news agencies in the world. And just as incessant as Reuters' news is the demand on its network. So when the agency decided to migrate its network from shared Ethernet to switched Fast Ethernet with an ATM backbone, it needed to rethink its network strategy. End-to-end network management based on RMON (Remote MONitoring) was a critical component of Reuters network. While a single RMON probe had worked well on a shared network, it couldn't monitor multiple switched segments. And multiple 100Mbit/s probes were prohibitively expensive. Reuters MIS manager Bryan Ginman found a cost-effective and non-disruptive way of implementing end-to-end network management, using the distributed RMON (dRMON) SmartAgent software on 3Com's Fast EtherLink XL 10/100 network interface cards (NICs), in conjunction with 3Com's Transcend dRMON Edge Monitor System.

Switching or bust

The Reuters network is a true 24-hour-a-day, seven-day-a-week operation; channelling vital live market data feeds to news networks, brokerage houses and bond traders. The network also supports a large cadre of developers who create Reuters' financial market software products, such as Treasury 3000 and R3FI. Until recently, increased Internet traffic, growing file sizes and overall network usage were pushing bandwidth utilisation on the 1,000-node network to 75 per cent of capacity. Video applications were also looming on the horizon. It was clear to Ginman that the existing network, based on Cabletron MMAC hubs, was not going to work for much longer.

After evaluating the alternatives on the market, Ginman opted for a switched network with an ATM backbone based on 3Com CoreBuilder 7000 High-Function ATM switches. "When I was designing this network, I designed it primarily for data, but with the capability to handle video and audio applications as well," says Ginman, explaining the leap from shared 10Mbit/s Ethernet to 155 Mbit/s ATM. Reuters also revamped its cabling infrastructure. New 100Base-TX cabling now runs from the ATM switches to SuperStack II Switch 1000 Ethernet switches at the edge of the network. At the desktop, Ginman's group replaced its existing Intel EtherExpress PRO/10+ NICs with 3Com Fast EtherLink XL 10/100 NICs to take advantage of their dRMON SmartAgent software. This software is part of the DynamicAccess software suite, an advanced set of drivers on 3Com NICs that helps optimise network performance, management, and control. The switches and the NICs also incorporate traffic prioritisation technology, which improves the quality of multimedia and real-time applications in switched Ethernet networks.

Regular RMON cannot make the grade

Now, the question was how to manage this new, switched network. Ginman and his staff found that the cost and potential downtime made RMON probes virtually impossible to implement. "When changing from a shared to a switched network, you can no longer use sniffers on just one segment because you cannot see the whole network due to its bridged nature," Ginman explains. "One of the options is to put probes that can 'look' at each segment coming primarily off the centre switches, that is, the CoreBuilder 7000 switches. Each segment would need one probe, or in some cases a RMON probe could handle two segments. Still, at this pace the costs on, for example, 100 segments, range between $600,000 and $1 million. That's a very costly solution when you consider the size of our network."

Even if Reuters' management had approved the cost of the upgrade, implementing it would have been extremely disruptive. To put the sniffer on the network, Reuters would have had to disable 24 desktops at a time, and given the kind of mission-critical activity going on, this was not a viable option.

Introducing Distributed RMON (dRMON)

That's when Ginman's group began looking at 3Com's dRMON technology. By distributing RMON intelligence to the end stations, MIS managers can use dRMON SmartAgent software to ease the administrative burden on the central management station. RMON statistics are collected by the dRMON SmartAgent software on 3Com NICs and are forwarded to a Transcend dRMON Edge Monitor System (running on a Windows NT server), which aggregates the statistics for all the stations on each VLAN (virtual LAN) or subnet. "That is your sniffer," Ginman says. "You can't put sniffers in the switches at the centre and the core of a switched network because the memory and processor overhead sends the costs of that switch into orbit. What dRMON does is make these groups of segments look like they are part of a shared network."

According to Ginman, one of the real values he sees in the dRMON SmartAgent software is that it supports all the RMON groups, including groups 8 and 9, which capture and decode packets as they are sent from the desktop. That is important for monitoring the kind of applications that now run over the Reuters network. "We want to see what type of traffic is coming through the pipe and make policy decisions," he says. "Say we find out that the World Wide Web is using a certain amount of bandwidth. We can then decide to adjust the bandwidth or make priority decisions." So far, dRMON SmartAgent software has been installed on more than 1,000 NICs. Tests of the effects of the software on the user's desktops and on network bandwidth have shown negligible, if any performance degradation. So having that extra level of control is worth it, especially when it doesn't require a massive investment in time and money at the desktop. "We're installing 10/100Mbit/s cards anyway," Ginman says, "and with the 3Com NICs, we get network connectivity and end-to-end management in one product."

Putting dRMON to the Test

Ginman tested the utilisation of bandwidth on the network from the software reporting data to the dRMON Edge Monitor and the effect of the software on the desktop CPU. "From our bandwidth tests, we estimated that the increased utilisation was two to three per cent on the desktop 10Base-T links and 0.4 per cent on the Edge Monitor 100Base-TX port." For the desktop CPU test, Ginman logged average CPU utilisation for more than one hour with the dRMON SmartAgent software turned on, and then for an hour with it off. "With the dRMON SmartAgent software on we saw an increased CPU utilisation of approximately six per cent," Ginman states. "This increase is inconsequential if you consider that a basic screen saver boosts utilisation approximately 20 per cent."

Paul Phillips

Read more on Networking hardware