Wi-Fi Order from Chaos: The Chicago Board of Trade

By David Haskin

April 25, 2003

Chaos is normal on the trading floor at the Chicago Board of Trade, but the initial use of WLANs there was particularly chaotic, until the board took control.

Traders wave frantically, scream out orders, enter trade information into a variety of computing devices, then rush off to another trading pit to make more trades. The media frequently shows chaotic scenes such as this from the floor of the Chicago Board of Trade (CBOT).

That's nothing, however, compared to the chaos in the airwaves that occurred when, about six years ago, traders of agricultural and financial futures and options started installing their own wireless networks on the trading floor so they could move around more freely. CBOT previously had installed only Ethernet access stations.

"We allowed them to put in their own access points and set up their own networks," said Jeff Komarek, network planning analyst for the CBOT. "It quickly became a huge problem -- it was chaos. There were coverage problems, they were fighting for bandwidth and there was no cooperation at all."

The only solution, according to Komarek, was for CBOT to take control by installing and running the wireless network for traders. "We realized we'd better reclaim the bandwidth," he said.

Taking Control

Initially, CBOT hired an outside firm to do a site survey, but that didn't work out, Komarek said.

"They weren't as knowledgeable about wireless as we were," he said. "And they certainly weren't knowledgeable about the trading environment and having a thousand or more people in one room all using wireless."

For example, the consultant wanted to put access points beneath the floor.

"But there was steel and plastic to go through that would have caused interference problems, not to mention all those bodies on the floor itself," he said. "And, it isn't even always possible to get under the floors."

As a result, he and his colleagues decided they could provide reliable, obstruction-free access by placing six access points -- three active units and three redundant units -- on the walls surrounding each of the two trading floors.

"That provided a clear line of sight for everybody, with no interference," he said. From the start, CBOT used 802.11 equipment, but the bandwidth in those early days was only 2Mbps.

Controlling Bandwidth and Security

Currently, Komarek said, about 500 traders use the wireless network while the majority still using the wired network. Not surprisingly, he expects ever-more traders to switch to the WLAN over time.

The trading firms that share the WLAN must find their own way, such as frame relay or T1 lines, to get the data from the network to their own backend systems. Komarek said primary responsibility for security also falls to the trading firms.

"We provide WEP and a few other things I'd rather not get into," he said. "But each trading firm is basically responsible for its own security."

Two of the biggest issues for Komarek's group are managing performance and preventing radio interference. The CBOT banned use of cordless phones, some of which operate in the same 2.4Ghz frequency range as the currently-deployed 802.11b network. In addition, there was a problem briefly with remote controls for the many televisions scattered around the floor. Some of those remote controls also used the 2.4GHz frequency range and CBOT banished those devices, too.

However, interference from Bluetooth remains an ongoing problem, according to Komarek. Wireless phones and handhelds brought on to the trading floor by traders increasingly have built-in Bluetooth, which sends out packets every second or so that look for other Bluetooth devices.

"One (Bluetooth) device may not be a problem, but ten devices are a problem," Komarek said. "We have to constantly send out notices to the traders saying these products must be turned off when they enter the floor. But we still get problems and, when we do, we have to go down to the floor and search for them and ask the traders to turn them off."

Bluetooth interference results in a marked performance hit, a critical issue with so many traders accessing a single 11Mbps WLAN, Komarek said. Another way CBOT tries to ensure reasonable performance is to limit individual users' throughput to 64Kbps, he added.

"Most people are satisfied with that, but we've had a couple of cases where users needed more bandwidth," according to Komarek. "We worked out a solution so that they used a terminal server to lower their bandwidth needs."

Multiple Networks

Unlike many enterprises, Komarek said he doesn't worry about which 802.11 standard the CBOT will migrate to. Rather, he said CBOT will install equipment supporting all the standards.

Currently, 802.11b is the only standard in use but he said his group has been testing 802.11a equipment, which it will roll out later in the current quarter. When more 802.11g products are available, Komarek and his colleagues will test and install them, too.

The trading floor of the Chicago Board of Trade is still chaotic, of course -- that's the nature of the business. Despite that chaos, though, Komarek and his colleagues at CBOT have managed to establish some order amidst the Wi-Fi chaos.

802.11 Planet Conference Will your users ever get a chance to roam like the traders? Join us at the 802.11 Planet Conference & Expo, June 25 - 27, 2003 at the World Trade Center Boston in Boston, MA. We'll get you started in our panel called Best Practices For Secure Wireless Roaming.



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