KVM in, Linux server up, we install the WLAN

So, now that the basic server was out of the way, we were ready to tackle the wireless network. Linksys loaned us a Dual-Band Wireless A+G Broadband Router, which is a WAN/LAN router, a four-port 10/100M bit/sec Ethernet switch and a wireless access point. The latter supports what Linksys calls Universal Wireless Access, which is to say it handles 802.11a, 802.11b and 802.11g.

Last week we asked if anyone had any ideas on how to get Serial Advanced Technology Attachment drives to work under Linux, and Mark Mills was the first to respond: “Install a 3Ware card. I’m new to Linux but 3Ware’s documentation made it fairly straightforward (even for a Windows user). If you are already familiar with Linux it will be a snap!” Mills went on to note: “64bit PCI slot + 3Ware Serial ATA controller = 185M byte/sec reads and 70M byte/sec writes in RAID 5.”

He also boasted: “My most recent accomplishment – 12 individual 250G byte Serial ATA drives on one Serial ATA RAID controller for a total of 2.25 terabytes . . . (put into RAID 5 comes to 2 terabytes of space) on a 5U server with 2 gigabit NICs, floppy, DVD-ROM, tape drive and N+1 redundant power supply.” Cool. We detect a kindred spirit.

Armed with this information we are planning to put together a RAID Serial ATA configuration, so we’ll let you know what we find out about the intricacies therein.

Anyway, we started off this series of Gearhead columns discussing the wireless LAN (WLAN) we set up for Jim Sterne’s recent Emetrics Summit. We’re getting into this in a roundabout kind of way and so far have covered the setup of our Raritan keyboard/video/mouse switch in our lab that reduced the amount of running around we have to do, and last week moved on to an overview of what’s new in the Red Hat Linux 9 software we loaded on our network server.

We were going to get into a detailed what’s what in this Linux release but we found an exhaustive summary at Guru Labs that tells you all you need to know and then some. Our experiences with Red Hat Linux 9 have so far been fantastic! It is fast, clean and it is a pleasure to play, er, work with.

So, now that the basic server was out of the way, we were ready to tackle the wireless network. Linksys loaned us a Dual-Band Wireless A+G Broadband Router (Model WRT55AG), which is a WAN/LAN router, a four-port 10/100M bit/sec Ethernet switch and a wireless access point. The latter supports what Linksys calls Universal Wireless Access, which is to say it handles 802.11a, 802.11b and 802.11g.

Note that the ports on the WRT55AG’s Ethernet switch support Auto-MDI/MDI-X. The specifications for 10Base-T and 100Base-TX define that two pairs of wires are used to connect two nodes. To do so the transmit side of the interface on one machine must be connected to the receive side of the other machine’s interface and vice versa.

This requires that the wires in the cable used to connect the nodes be “crossed.” Now, the design of standard unshielded twisted pair cabling with RJ-45 connectors uses straight-through wiring so the jacks on hubs have ports physically configured to be crossed over. Thus, NIC cards normally are configured to be “straight” (called a Medium Dependent Interface, or MDI), while hubs are normally configured as “crossed” (called a Medium Dependent Interface-Crossed, or MDI-X). So, if you need to connect a NIC directly to another NIC or hub to another hub, you’ll need a cross-over cable.

Many hubs have a special port that lets you connect the hub to another hub’s MDI-X port without using a cross-over cable. This port, configured as an MDI port, also is called an uplink port or MDI-II port.

The Auto-MDI/MDI-X feature automatically determines whether the port should act as an MDI or an MDI-X port.

Anyway, to support all three wireless communications standards the WRT55AG contains two wireless radios. One radio runs at 2.4 GHz for 802.11b and 802.11g service, providing 11M bit/sec and 54M bit/sec, respectively. The second radio runs at 5 GHz and supports 802.11a, which, like 802.11g, supports 54M bit/sec links. All this and the device is the same size as the company’s previous access points.

Getting the WRT55AG running was a piece of cake. We configured it to provide Dynamic Host Configuration Protocol service but, because of the need for the WLAN to be open, we didn’t enable Wired Equivalent Privacy.

We used a Linksys Dual Band Wireless A+G Notebook Adapter (WPC55AG) to test the wireless out and – wow! – the performance of 802.11a and 802.11g is awesome.

So, there was the infrastructure, next week, we fire her up!

Details, details, details to gearhead@gibbs.com.