The Pitch & Product

As gigabit Ethernet continues its inexorable march into SOHO networks, prices are dropping and "10/100/1000" is seen more frequently on product front panels and retail boxes where "10/100" once appeared. But it's still not very easy to find a 4 to 16 port gigabit switch or other SOHO gigabit products other than Ethernet adapters with jumbo frame capability.

Jumbo frames are simply Ethernet frames (packets) larger than 1500 Bytes. If your computer and OS are up to it, their use can boost networking throughput significantly.

TIP: If you'd like additional background on jumbo frames try this article.

Until now, ASUS has been the only manufacturer to support jumbo frame capability in a SOHO-oriented product, namely its RX3141, which I looked at a few months ago. So when NETGEAR recently told me that it was updating its GS108 8 port gigabit switch to support jumbo frames, I asked them to send one over so that I could check it out. An engineering sample arrived in short order that, aside from being labeled "engineering sample" and not coming in a retail box, was the same as what they'll be shipping.

Update 8/6/2005 - A reader pointed out that SMC's SMC8508T also supports up to 9K jumbo frames at a similar price point to the GS108 and has been available for some time.

Figure 1 shows the GS108 uses an Altima (acquired by Broadcom in 2000) AC388 switch chip and Broadcom BCM 5014 quad PHY. This combo is used instead of the Broadcom BCM5385 5 port switch chip used in the RX3141, as well as D-Link's DGL-4100 and DGL-4300 [reviewed here] gaming routers, and 5 port gigabit switches from Belkin, Linksys, TRENDnet and others.

Figure 1: GS108 board
(click image to enlarge)

With this chipset, jumbo frame support can be programmed to be on or off. But it's a factory-programmed option - probably via the Atmel 93C46 EEPROM shown in Figure 1 located between the other two chips. So this means that existing GS108's can't be field-upgraded.

Since the GS108 is a plain ol' unmanaged switch, there's nothing you need (or can) do to it to use jumbo frames. All you need to do is have a gigabit Ethernet NIC that supports jumbo frames and enable the feature there. Note, however, that once you enable jumbo frames, everything that computer communicates with on your LAN also must support jumbo frames. In addition, everything needs to be set to use the same size jumbo frame.

You'll know right away if you try to use a jumbo frame-enabled PC with non-jumbo frame gear. For example, everything worked fine when I network-browsed over to another jumbo frame-enabled PC. But when I tried to web browse, I got very slow page loads and sometimes none at all. This was because my router's 10/100 Ethernet switch that I had the GS108 uplinked to couldn't properly deal with the jumbo-sized data packets I was sending.

Tags: gigabit, Netgear, Switch reviews,

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