Also: Google knocks Microsoft off Dell PCs; Are rootkits really evil?; and more
Broken segments
Regarding “Data center networks often exclude Ethernet”: Yes, InfiniBand is becoming popular, but not for the main reason stated here. Recent (within the last 10 years) switches no longer use store-and-forward once the bridge table is constructed.
Here’s an excerpt from a “Networking 101” article I wrote about Layer 2: “A few years later, the old store-and-forward method of bridge operation was modified. New switches started only looking at the destination MAC address of the frame, and then sending it instantly. Dubbed ‘cut-through forwarding,’ presumably because frames cut through the switch much more quickly and with less processing. This implies a few important things: A switch can’t check the CRC to see if the packet was damaged, and that implies that collisions needed to be made impossible.”
A full milisecond of latency is horrible, and if that’s happening you should probably upgrade your switches, or limit your broadcast domain. Anything less than 0.5 ms of latency in an Ethernet segment is considered “broken.”
Charlie Schluting
Unix lead, College of Engineering
Portland State University
Portland, Ore.
Let consumers decide
Regarding “Google knocks Microsoft off Dell PCs”: I may be the minority, but I don’t use anything Google. None of it is useful to me, and I think what Dell is doing is just making things worse. People already complain about the massive amounts of software that companies like Dell pre-install; this is just making things worse. I say let the consumers decide what they want and stop trying to push things on them.
Justin Naylor
Spokane, Wash.
Taking a worldview
Regarding “$100 laptops? …Not yet”: The One Laptop Per Child and low-cost PC initiatives are admirable goals; however, both strike me as being nothing more than new business initiatives. Current PC users upgrade their hardware every few years and usually discard old but fully operational hardware. Maybe with volunteers and tax credits, these old PCs (or parts thereof) could be reused instead of contaminating landfills. If we are going to change the world, why not take a worldview?
Jeff Black
Arlington, Va.
Say no to Gig desktops
Regarding “Gartner analyst: Resist Gig Ethernet”: As far as gigabit to the desktop, to an extent the story has it right. But for trunks to closets as well as server connections, it is the sane way of doing things. Want to spend time with QoS trying to put 10 pounds of coffee in a five-pound can? Prioritization schemes are necessary pains in the butt, not something to design a system or network around. My company does gigabit trunks over wavelength division multiplexing in the metropolitan area on a shoestring budget, and the users are much happier than they used to be. Speed thrills. But gigabit to the desktop, on the other hand, has been more liability than asset, given the ability of a single machine to push huge amounts of traffic.
Darrell Jones
Eugene, Ore.
Root of all evil
Regarding “Are rootkits really evil?”: Sebek is a good example of a rootkit used to monitor system activity on a honeypot. It sends the activity data over a covert channel to a Sebek controller. The value in this is that the data bypasses the system’s TCP/IP stack and is undetectable by a packet sniffer on the system itself. Would I do this on a production system? Maybe, maybe not. The traffic can still be seen by an intrusion detection/prevention system sensor after it gets on the wire, so if a system is compromised, you can still detect malicious traffic. But it makes it very difficult for an attacker to detect the monitoring of the system activity. If you could use a tool like this for remote logging or monitoring, I think it could be very beneficial.
David Erban
Mission Viejo, Calif.
Rootkits are becoming more and more prevalent as the months go by. Having a piece of rootkit code that can hide spyware and viruses is a godsend for malware writers as their malware can go undetected for longer and can be harder to remove. Ordinary users don’t want to have to wipe their hard drive to remove a piece of code that is hiding a piece of malware that pops up ads at them every now and again.
Rootkits will become more customized and harder to find, as their signatures will change with each new attack. We all have a rocky road ahead with rootkits.
Stephen Marsh
Administrator
www.antirootkit.com
Dublin, Ireland
Research telco issues
In her column, “Telco bashing: It’s just their turn”, Johna Till Johnson writes: “The message? For God’s sake, don’t own facilities if you can possibly help it. Don’t make money, or you’ll get sued. And never, ever cooperate with the government – at least if you’re a telco.”
I think the issue is a lot more complicated than this simple statement. Maybe the best thing to do is to do a series of in-depth articles about the telco issues. I’m tired of all the knee-jerk reactions based on innuendo not real research.
Will Bigelow
Waltham, Mass.
