Gigabit Ethernet For the Frugal Admin

High performance isn't as spendy as you might think if you know where to make some tradeoffs.

By Carla Schroder | Posted Jan 18, 2006
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Do you need Gigabit Ethernet? With 10 Gigabit Ethernet already in use you're falling far behind. If you're still ambling along with pokey old 100Base-TX, you're practically obsolete.

Seriously, upgrading to Gigabit Ethernet on the LAN is simple and painless. Starting with switches and servers gives you the most bang for the buck, then figure out which individual workstations really need it. Users who move a lot of large files around, like graphics and sound, horrid PowerPoint archives, coders who are working with large source trees, creative persons generating large multi-media extravaganzas or admins managing large remote backups make good use of fatter pipes.

You may not have to upgrade your existing cabling. Ordinary four-twisted-pair Cat5 (define) should work, though Cat5e is better. Chances are your Cat5 is really Cat5e anyway; read the cable markings to find out.

Cat6 twisted-pair cabling, the next generation of Ethernet cabling, costs more than Cat5e. It is a heavier gauge (23 instead of Cat5's 24), meets more stringent specifications for crosstalk and noise and it always has four pairs of wires.

You may be foiled by cheapie Cat5 that has only two twisted pairs. Don't forget your wall jacks, sometimes those are cheapies too. Once you've sorted out your cabling and connections, it's time go shopping for switches. We'll look at some examples from various vendors. I don't have any particular favorites; this is a random sampling selected from devices that either I've used, or my friends have plugged into their workplaces.

It's not necessary to sell your kidneys to afford Cisco or Nortel for your LAN. Linksys, D-Link, Netgear, US Robotics (which bought 3Com), SMC and Belkin all have good product lines, and cost a lot less than the elite snooty ones.

The Switches of Eastwick
No, we don't want hubs. Collision domains (define) are so last millennium. You really have to be pinching pennies to settle for a hub over a switch.

A nice thing about modern Ethernet switches is MDI/MDI-X (medium dependent interface) (define), which auto-detects the type of cable plugged into a port, so you don't have to juggle crossover and straight-through cables anymore. (Yes, this is old news, but some folks are still stuck on old equipment.) I used to carry a little Ethernet crossover adapter on my keyring just to avoid cabling hassles.

As long as you're hanging useful gadgets on your keyring, try the Ethernet loopback jack, for quick connectivity checks.

Managed switches used to be high-priced enough to make accounting persons uncomfortable; now even Gigabit Ethernet managed switches are not going to break the bank. Is it worth spending more for a managed switch? It depends on what you want to do. If you want to be able to sniff all network traffic, set up VLANs, do port trunking, priority queueing or connect to a Gigabit backbone, then you want a managed switch. If all you want is to link hosts on a LAN and not muck with these things, an unmanaged switch is for you.

Managed switches have Web-based administration consoles, so you don't have to worry about operating system compatibility. 16-port managed Gig-E switches with all the bells and whistles cost from around $260 to $350:

Netgear ProSafe GS716T. Supports SNMP and jumbo (9000 byte) frames.
Linksys SRW2016 has a serial console port.
This 48-port D-Link DGS-1248T behemoth costs around $900. Supports SNMP, jumbo frames, QoS, per-port access controls, copper and fiber gigabit and spanning tree.

If you want to connect to a gigabit backbone or server, make sure your switch supports the cabling. There are two types: fiber and copper, and not every device supports both.

Jumbo frames, you ask? What's wrong with our faithful, reliable old 1500-byte frames? Well, when you're pushing bits at gigabit speeds, bigger frames = more efficiency. The current standard is 9000 bytes. Not all gigabit hardware supports jumbo frames.

Port trunking? This means combining several switch ports to create a fatter pipeline. You can connect a switch to a switch, or a switch to a server if it has an NIC that supports link aggregation.

VLANs? Create logical subnets, instead of physically dividing them up with hardware. Very easy and flexible to organize your LAN without re-wiring everything.

If you can live without SNMP, jumbo frames, and connecting to a gigabit backbone, take a look at TRENDnet's TEG-224WS 26-port smart switch. "Smart" switches are less-featureful managed switches. It has plenty of useful features for under $160, including VLANs, port mirroring, and QoS. This little box makes a nice LAN gigabit backbone.

Unmanaged switches come in smaller sizes, like the five-port SMC SMCGS5. It costs around $50, about the same as a 10/100 switch.

The US Robotics 16-port unmanaged switch goes for around $230.

Network Interface Cards
Gig-e has made even boring old NICs interesting. PCI NICs for client PCs range from $15- $125. Feature sets vary, like wake-on-LAN, PXE boot, PCI-Express support and jumbo frame support. Don't expect full gigabyte speeds on older machines with slower PCI buses. You'll see a big difference on modern motherboards with gig-e support built in.

Server-quality NICs go as high as $400, and come with multiple ports, fiber Gigabit support, and link aggregation.

Linksys has a USB 10/100/1000 NIC for about $60. It's pointless over USB 1.1, which maxes out at 11 megabits per second, but it's an easy upgrade on machines equipped with USB 2.0, or 480 mbps. It's not quite gigabit speed, but it saves opening the case, and might be your only reasonable option for some laptops.

If your laptop has genuine 32-bit Cardbus, you'll get good LAN speeds with a Cardbus adapter like the StarTech Gigabit CardBus NIC. This little gem works great, and blatantly supports Linux. A steal at around $50.

Gigabit Router
Maybe I've been hanging out with the wrong crowd, or maybe an integrated Gigabit router/VPN/firewall is a wrong thing to want, but I haven't seen one that really works well, with one exception: the D-Link DGL-4100 Broadband Gaming Router. At under $140, it's a nice buy. While it's targeted at gamers, it has one feature usually found only in higher-end devices: QoS-type traffic prioritization on the WAN port. This makes it a great little VoIP router: Remember, it's latency that clobbers games and VoIP, not just lack of bandwidth.

If you have any gig-e tips or tricks or hardware to recommend, especially wireless, please feel free to drop me a line for future gig-e articles.

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