Layer 2 switches

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Cost-effective traffic controls can bring your LAN up to speed

By J.B. Miles

Special to GCN

If your legacy Ethernet LANs are stretched to the breaking point under the weight of new users, servers and high-end applications, try replacing old Ethernet hubs with one or more 10/100-Mbps Ethernet switches.

All the switches in this guide are reasonably priced, flexible and suitable for running small networks or for connecting many small workgroups at larger sites. Unmanaged eight- or 16-port switches sell for as little as $20 per port, and many managed 16- or 24-port switches sell for as low as $100 per port.

Garrett Communications' Magnum switches come with eight to 24 10/100-Mbps ports and range in price from $599 to $1,199.

Unlike hubs, which share available bandwidth among attached devices, nonblocking switches provide dedicated 10- or 100-Mbps bandwidth to networked PCs, workstations and servers. And if you can't yet part with your existing hubs, you can use 10/100 switches to connect them for better network segmentation.

At the desktop, 10/100 switches are the best possible devices for connecting multiple users to the network at top speeds.

The accompanying chart lists 66 10/100 dual Ethernet workgroup switches from 26 manufacturers. They are equipped with eight, 16 or 24 auto-sensing 10/100 ports to determine the speed of attached devices and automatically configure the ports for 10-Mbps or 100-Mbps throughput. All can automatically negotiate between half- and full-duplex modes'the latter effectively creating dedicated 20-Mbps or 200-Mbps connections.

Most switches listed also provide shared or dedicated 10/100 uplinks to other switches or network backbones, and some even provide one or two dedicated Gigabit Ethernet links for especially heavy bandwidth requirements.

The products in this guide are Layer 2 switches, meaning they operate at the second, or data link, layer of the Open Systems Interconnection model. Their function is to check incoming network traffic, keep track of the physical addresses of all stations attached to their ports and forward traffic to specific station addresses according to the forwarding tables they have built. Layer 2 switches can deliver data at wire speeds because they don't have to examine individual data packets.

Layer 3 switches, also called routing or IP switches, perform both switching and routing tasks. Because they make heavy use of integrated circuits, specialized crossbar switching fabric, fast CPUs and other high-end components, they are expensive but well-suited to network backbone service.

But less expensive Layer 2 switches also provide an extensive range of features and options, making them cost-effective for managing traffic at the workgroup and small network levels.

Hewlett-Packard's ProCurve Switch 408 is an unmanaged, eight-port switch in a rackmount design. It is priced at $299.

Among their features and characteristics are:

Auto-sensing. A switch's auto-sensing capability means it can determine the speed of attached devices and automatically configure the ports for 10-Mbps or 100-Mbps throughput. It does this by reading the speed of the network adapter or network interface card attached to the networked PC or server.

Auto-negotiation. A switch's ability to automatically negotiate between half- and full-duplex modes is extremely useful for particularly bandwidth-hungry client applications, such as a remote computer-aided design and manufacturing workstation.

Full-duplex Fast Ethernet mode temporarily shuts down the Ethernet carrier-sense multiple-access with collision detection and loopback functions, allowing the switch to provide a theoretical bandwidth of 200 Mbps; that is, 100 Mbps in each direction.

But this capability comes at the expense of some of the collision detection features of half-duplex mode and should be only be used for isolated high-speed workstations where collision detection isn't required.

Top aggregate bandwidth. Aggregate bandwidth is the top theoretical speed limit of each switch and is related to the number of ports employed. Thus, the aggregate bandwidth of an eight-port switch running at 100 Mbps per port is 800 Mbps, while it's 1.6 Gbps for a 16-port switch.

Store-and-forward. The simplest switches operate as cut-through devices, meaning they only examine a packet's destination before forwarding it. More advanced store-and-forward switches analyze the entire packet before forwarding it. The tradeoff? Store-and-forwarding eliminates many traffic errors but takes longer than the cut-through technique.

Unmanaged. Workgroup switches may be managed or unmanaged. Unmanaged switches are plug-and-play devices and are a good match for small, flat networks with a mixture of 10-Mbps and 100-Mbps legacy devices. They can automatically learn network addresses and can handle both auto-sensing and auto-negotiation.

The best thing about them is their price. 3Com Corp.'s Office Connect Dual Speed Switch 8 is priced at $210, and Accton Technology Corp.'s popular CheetahSwitch Workgroup 3008A has been reduced to $199. D-Link Systems Inc.'s DSS8+ can be bought for as low as $87 from third-party vendors, and ARK Technologies' $75 CT2208D unmanaged switch is the cheapest I've seen'less than $10 per port.

Tips for buyers

' Choose the right path: Dual-speed 10/100-Mbps switches are the best hardware for migrating from Ethernet to Fast Ethernet.

' Remember that switches with one or more dedicated uplinks provide better expansion paths than those with shared-port uplinks.

' Consider a vendor with a large family of switch products if you know you'll be expanding your networks again.

' Buy a managed switch if you need to monitor and report on hubs, bridges, routers and other switches on the network.

' Plan carefully before making network moves and changes.

Managed. Managed switches, in the $1,000 and up price range, are more expensive because they perform more services. Network management features are important when remote switch management is required, or when several switches are linked as part of a more complex network than a LAN.

Products such as Allied Telesyn International Corp.'s $1,369, 16-port AT-8118 and all of Cisco Systems Inc.'s Catalyst 2900XL models'priced at $964 and up'come with proprietary management software. The software most often combines Simple Network Management Protocol and Remote Monitoring network management standards, with their own network management flavors and a little Web-based management tossed in.

Scalability. Simply adding users to a switch or connecting your switch to a network backbone switch is one way to scale your network upward. Rackmountable switches are more easily scalable than standalone desktop switches. Intel Corp.'s high-end switches with built-in Scalable Stacking Technology incorporate a scalable backplane into the switch stack. But the company's standalone Express 410T and 510T models listed here don't offer this feature.

VLAN support. Managed Layer 2 switches such as Accton's $785 CheetahSwitch Workgroup 3514F and all of IBM's 8275 series can support virtual LANs, either as a bundled or optional feature. A VLAN is a group of network resources or users on different network segments that communicate as if they were on the same wire.

Users can be linked by media access control addresses, IP addresses, network protocols or even the port numbers of a LAN switch into a virtual grouping that can share network resources and bandwidth.

VLANs are tied to Layer 2 technology, however, and as Layer 3 switches providing full Gigabit Ethernet wire-speed routing enter the market, they may disappear.

Diagnostic port LEDs. LED indicators at each switch port generally indicate the activity of the link, such as 10-Mbps or 100-Mbps bandwidth utilization or collision/full-duplex. An on/off switch LED light is included with virtually all switches.

Media compatibility. A big advantage to 100Base-T Fast Ethernet is that it runs over the same 10Base-T media that standard Ethernet uses. 100Base-TX'two pairs of data-grade Category 54 unshielded and shielded twisted-pair wiring'and 100Base-FX'two strands of multimode fiber'have emerged as the most popular cabling schemes in most wiring closets, so be sure that your switch supports them with appropriate connectors. The most popular media for Gigabit Ethernet uplinks is 1000Base-SX, which uses multimode fiber, but the more versatile, copper-based 1000Base-CX technology is coming on strong.

J.B. Miles of Pahoa, Hawaii, writes about communications and computers.

10/100-MbpsportsExpansionConfigurationKey switching featuresPrice
Accton Technology Corp.

Irvine, Calif.
Workgroup 3008A
UnmanagedEightOne shared 10/100
uplink port
DesktopStore-and-forward, full- and half-duplex, auto-negotiation, plug-and-play,self-learning configuration$199
Workgroup 3016A
Workgroup 3024C
Workgroup 3514F
Telnet, Web-based
12Optional 1000Base
(gigabit) uplink
RackmountStore-and-forward, full- and half-duplex, auto-negotiation, VLAN support$785
Workgroup 3526F
Allied Telesyn International Corp.
Sunnyvale, Calif.
AT-8118-10AT-View, SNMP, Telnet, Web-based16 Two optional 10/100TX or 100FX uplink portsRackmountCut-through or store-and-forward, full- and half- duplex, auto-negotiation,automatic address learning$1,369
ARK Technologies
Orange, Calif.
CT2208D/CT2208DIUnmanagedEightOne shared MDI-IIuplink portDesktop or rackmountStore-and-forward, full- and half-duplex, auto-negotiation$75
CT2216DUnmanaged16Two shared MDI-IIuplink portsDesktop or rackmountSame$185
Asante Technologies Inc.
San Jose, Calif.
FriendlyNet FS4008PUnmanagedEightOne 10/100 uplink portDesktop orrackmountStore-and-forward, full- and half-duplex, auto-negotiation$149
FriendlyNet FS4016PUnmanaged16One 10/100 uplink portSameSame$549
FriendlyNet FS4024PUnmanaged24One 10/100 uplink portSameSame$689
IntraSwitch 6224MSNMP, Telnet,Web-based24Two MDI-II uplinkportsRackmountSame$999
Cisco Systems Inc.
San Jose, Calif.
Catalyst 2912 XLCiscoWorks, SNMP, Telnet, Cisco CGMP12N/ARackmountStore-and-forward, full- and half-duplex, auto-negotiation, VLAN support$964
Catalyst 2912MF XL Same12Two 10/100 uplinkportsRackmountSame$1,001
Catalyst 2924 XLSame24N/ARackmountSame$1,315
Catalyst 2924C XL Same24Two 100Base-FXportsRackmountSame$1,927
Catalyst 2924M XLSame24Two 10/100 uplinkportsRackmountSame$1,614
Compex Inc.
Anaheim, Calif.
PS2208 Pocket SwitchUnmanagedEightOne shared 10/100uplink portDesktopStore-and-forward, full- and half-duplex,auto-negotiation$131
D-Link Systems Inc.
Irvine, Calif.
DSS 8+UnmanagedEightOne MDI-II uplinkportDesktopStore-and-forward, full- and half-duplex, auto-negotiation, VLAN support$87
DSS 16+Unmanaged16Two MDI-II uplinkportsDesktopSame$297
Edimax Computer Co.
Santa Clara, Calif.
ES-3108PUnmanagedEightOne shared 10/100uplink portRackmountStore-and-forward, full- and half-duplex, auto-negotiation$149
Farallon Communications Inc.
San Leandro, Calif.
Fast Starlet Palm SwitchUnmanagedEightN/ADesktopStore-and-forward, full- and half-duplex, auto-negotiation$153
Fast Starlet Switch 16Unmanaged16One 100Base-FXportRackmountSame$378
Fast Starlet Switch 24Unmanaged24SameRackmountSame$396
Garrett Communications Inc.
Fremont, Calif.
Magnum 4K8UnmanagedEightOne or two optional 100Base-FX portsRackmountStore-and-forward, full- and half-duplex, auto-negotiation$599
Magnum 4K16Unmanaged16SameRackmountSame$899
Magnum 4K24Unmanaged24SameRackmountSame$1,199
Hewlett-Packard Co.
Palo Alto, Calif.
ProCurve Switch 408UnmanagedEightOne MDI/MDI-X portRackmountStore-and-forward, full- and half-duplex, auto-negotiation$229
ProCurve Switch 1600MSNMP, Telnet, Web-based16One MDI/MDI-X portRackmount Same$1,099
ProCurve Switch 2224Unmanaged24One open transceiver slotRackmountSame$529

VendorProductManaged/unmanaged10/100-Mbps portsExpansionConfigurationKey switching featuresPrice
Hawking Technologies Inc.
Irvine, Calif.
Model PN636ESUnmanaged16Two 10/100 uplink portsRackmountStore-and-forward, full- and half-duplex, auto-negotiation$321
Model PN2400ESUnmanaged24SameRackmountSame$445
IBM Corp.
Armonk, N.Y.
8275 Series Model 318SNMP, RMON, Web-based161000Base-SX and 100Base-FXv port optionsDesktop, rackmountStore-and-forward, full- and half-duplex, auto-negotiation, VLAN support$1,425
8275 Series Model 322Optional20SameSameSame$995
8275 Series Model 326Optional24SameSameSame$715
Intel Corp.
Santa Clara, Calif.
Intel Express 410T Standalone Switch Intel Device View, SNMP, RMON, Web-based16, 24N/ARackmountStore-and-forward, full- and half-duplex, auto-negotiation$546
Intel Express 510T Standalone SwitchSame24N/ARackmountSame$1,570
Kingston Technology Co.
Fountain Valley, Calif.
KNS800/WGUnmanagedEightUTP port 5DesktopStore-and-forward, full- and half-duplex, auto-negotiation$152
Lancast Inc.
Nashua, N.H.
CenturySwitch 3508-11
with Fiber Uplink
UnmanagedEightOne 100Base-FX uplink portDesktopStore-and-forward, full- and half-duplex, auto-negotiation$359
CenturySwitch 3508-01UnmanagedEightN/ADesktopSame$539
CenturySwitch 3512-01Unmanaged12N/ADesktopSame$899
Linksys International
Irvine, Calif.
DSSX12Unmanaged12One 100Base-FX uplink portDesktopStore-and-forward, full- and half-duplex, auto-negotiation$358
Lucent Technologies Inc.
Murray Hill, N.J.
Cajun P120 Workgroup SwitchCajun P120 Manager with SNMP, RMON, Lucent SMON24Optional 10/100, 100Base-FX or 1000Base-SX/LX portsDesktopStore-and-forward, full- and half-duplex, auto-negotiation$1,755 GSA
Marconi Communications Corp.
Warrendale, Pa.
Fore ES-1000Unmanaged22Two optional 1000Base-SX/LX portsRackmountStore-and-forward; expansion modules
for addition of up to four 10/100 ports
Network Peripherals Inc.
Milpitas, Calif.
NuSwitch DS12ASNMP, RMON, Telnet, Web-based, console port12Optional 100Base-FX uplink portRackmountStore-and-forward, full- and half-duplex, auto-negotiation$1,193
NuSwitch DS16Same16One 10/100 uplink port or optional 100Base-FX portRackmountSame$1,387
Nortel Networks Corp.
Brampton, Ontario
BayStack 70-8TUnmanagedEightOne MDI/MDI-X push-button optionDesktopStore-and-forward, full- and half-duplex,
BayStack 70-16TUnmanaged16SameDesktopSame$595
BayStack 70-24TUnmanaged24SameRackmountSame$994
OvisLink Technologies Corp.
City of Industry, Calif.
Ether-FSH8TXUnmanagedEightN/ADesktopStore-and-forward, full- and half-duplex, auto-negotiation$138
SMC Networks
Irvine, Calif.
EZ Switch II Model 6308TXUnmanagedEightOne 10/100 uplink portDesktopStore-and-forward,
full- and half-duplex, auto-negotiation, self-configuring
TigerSwitch 10/100 Model SMC6912MSMC EliteView, SNMP, RMON12Two 100Base-FX portsRackmountSame$986
TigerSwitch 10/100 Model SMC6924MSMC EliteView, SNMP, RMON24SameRackmountSame$1,232
3Com Corp.
Santa Clara, Calif.
OfficeConnect Dual Speed Switch 8UnmanagedEightOne MDI/MDI-X uplink portDesktopStore-and-forward, full- and half-duplex, auto-negotiation$210
OfficeConnect Dual Speed Switch 16Unmanaged16One MDI/MDI-X uplink portDesktopSame$390
Trendware International Inc.
Torrance, Calif.
TE100-S1616Unmanaged16One shared MDI-II port, optional MDA 100Base-FX portRackmountStore-and-forward, full- and half-duplex,
Unicom Electric Inc.
Rowland Heights, Calif.
Dyna Switch 16Unmanaged16One fixed 10/100RackmountStore-and-forward, full- and half-duplex, auto-negotiation, optional VLAN support$349
Smart-Switch/24SNMP, RMON24One fixed 10/100RackmountSame$1,575

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