Did Cisco Systems Inc. do the right thing a couple of months ago when it bought Arrowpoint, a startup making load balancing equipment, for a cool $5.7 billion?

The jury is still out, judging by an ongoing discussion on NANOG – the North American Network Operators' Group, a forum used by many ISPs to swap tips on how to run their networks. A couple of correspondents have been heavily critical of Arrowpoint’s CS100 switch, in one case blaming it for a site melt-down. Others, however, take the opposite view, saying that Arrowpoint gear has some fundamental advantages over the competition.

Cisco dismisses criticism of Arrowpoint as out of date. It says there were some hardware problems, which have been fixed. And in any case some analysts say, it bought Arrowpoint for its software and its skilled staff. "Arrowpoint switches are made with open market parts," says Peter Christy, director and senior analyst for Jupiter Communications Inc. "It seems to me they bought them for the software and engineers."



Cisco plans to port Arrowpoint’s software across its range of switches and integrate it into its IOS operating system over time (see Cisco Finds A Soft Spot for ArrowPoint). Arrowpoint software, in other words, could end up underpinning Cisco’s future, so it’s important to figure out whether there’s any substance to the criticisms on NANOG.

Let’s start by explaining what Arrowpoint’s load balancing equipment comprises and what it does. It’s a switch loaded with software that sits in front of server farms, distributing traffic among servers. What makes Arrowpoint different is its software, which looks deep into packet headers to identify high priority users or transactions by identifying URLs or cookies. This info is then processed using a set of pre-defined rules to pinpoint the server that should handle each packet. This in turn is used to control the switch, which forwards the data to the right server.

Much of the current discussion on NANOG was triggered by PublicHost, a web hosting company that posted the results of tests that it conducted on Arrowpoint’s CS100 switch for six months last year. PublicHost concluded that the CS100 wasn’t man enough for the job and ended up going with an alternative solution.

PublicHost hosts more than 5,000 Web sites and was looking for a switch that would enable it to apply at least five rule sets per site. Arrowpoint had said that its CS100 switch would be able to handle 5,000 rule sets, according to Karyn Ulriksen, director of network operations for PublicHost. When PublicHost tested the switch, however, it couldn’t handle more than 30 rule sets, she says. There was insufficient memory, and the only way of solving the problem was to buy Arrowpoint’s bigger switch, the CS800, which PublicHost considered to be too expensive.

PublicHost also identified a problem in Arrowpoint software, which caused the device to crash if it had to handle more than 225 simultaneous file transfer protocol (FTP) connections even though it had been configured to handle more than 1,000. To make matters worse, the switch had to be powered down and rebooted before it would disengage the connections.

The discussion of PublicHost’s test results on NANOG has also drawn attention to a case in which problems with an Arrowpoint CS100 appear to have prolonged a site meltdown. The customer involved, Slashdot.org, a networking community site owned by Andover.Net , had its site paralyzed by distributed denial of service attacks in May. When it recovered from those problems, it discovered that settings in its Arrowpoint gear were screwed up and two ports had failed. It took another 30 hours to iron out the problems, details of which are published in an article on Slashdot.org’s site, on http://slashdot.org/articles/00/05/17/1318233.shtml.

Although PublicHost and Slashdot.org have had poor experiences, other participants in NANOG’s discussion praise Arrowpoint and cite instances of blistering performance. This is mainly because packet forwarding is handled in hardware even though the routing decisions are made in software. The hardware is in the form of ASICs - application specific integrated circuits.

Arrowpoint isn’t alone in this respect. Other vendors with equivalent products include. Alteon WebSystems Inc and. Foundry Networks Inc . Arrowpoint has an edge in some circumstances, according to Tony Bourke, a participant in the NANOG discussion. In a July 10 contribution, he says: "ArrowPoints are probably my favorites, although I certainly enjoy using Alteon and Foundry load balancers. But like all load balancing products, not all work in every case."

by Marguerite Reardon, senior editor, Light Reading, http://www.lightreading.com