Layer 2 switches

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• Sep 06, 2000

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.

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

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.

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.

Hewlett-Packard's ProCurve Switch 408 is an unmanaged, eight-port switch in a rackmount design. It is priced at $229.

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.

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.

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.

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 OfficeConnect 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 DSS-8+ 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.

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.

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.

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.

Vendor	Product	Managed/ unmanaged	10/100-Mbps ports	Expansion	Configuration	Key switching features	Price
Accton Technology Corp. Irvine, Calif. 949-707-2400 www.accton.com	CheetahSwitch Workgroup 3008A	Unmanaged	Eight	One shared 10/100 uplink port	Desktop	Store-and-forward, full- and half-duplex, auto- negotiation, plug-and-play, self-learning configuration	$199
	CheetahSwitch Workgroup 3016A	Unmanaged	16	Same	Desktop	Same	$325
	CheetahSwitch Workgroup 3024C	Unmanaged	24	Same	Desktop	Same	$544
	CheetahSwitch Workgroup 3514F	SNMP, RMON, Telnet, Web- based	12	Optional 1000Base (gigabit) uplink	Rackmount	Store-and-forward, full- and half-duplex, auto- negotiation, VLAN support	$785
	CheetahSwitch Workgroup 3526F	Same	24	Same	Rackmount	Same	$979
Allied Telesyn International Corp. Sunnyvale, Calif. 408-730-0950 www.alliedtelesyn.com	AT-8118-10	AT-View, SNMP, Telnet, Web- based	16	Two optional 10/100TX or 100FX uplink ports	Rackmount	Cut-through or store- and-forward, full- and half- duplex, auto-negotiation, automatic address learning	$1,369
	AT-8126XL	Same	24	Same	Rackmount	Same	$939
	AT-FS716	Unmanaged	16	N/A	Rackmount	Same	$411
ARK Technologies Orange, Calif. 714-997-4597 www.arkpc.com	CT2208D/CT2208DI	Unmanaged	Eight	One shared MDI-II uplink port	Desktop or rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$75
	CT2216D	Unmanaged	16	Two shared MDI-II uplink ports	Desktop or rackmount	Same	$185
Asante Technologies Inc. San Jose, Calif. 408-435-8388 www.asante.com	FriendlyNet FS4008P	Unmanaged	Eight	One 10/100 uplink port	Desktop or rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$149
	FriendlyNet FS4016P	Unmanaged	16	One 10/100 uplink port	Same	Same	$549
	FriendlyNet FS4024P	Unmanaged	24	One 10/100 uplink port	Same	Same	$689
	IntraSwitch 6224M	SNMP, Telnet, Web-based	24	Two MDI-II uplink ports	Rackmount	Same	$999
Cisco Systems Inc. San Jose, Calif. 408-526-4000 www.cisco.com	Catalyst 2912 XL	CiscoWorks, SNMP, Telnet, Cisco CGMP	12	N/A	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation, VLAN support	$964
	Catalyst 2912MF XL	Same	12	Two 10/100 uplink ports	Rackmount	Same	$1,001
	Catalyst 2924 XL	Same	24	N/A	Rackmount	Same	$1,315
	Catalyst 2924C XL	Same	24	Two 100Base-FX ports	Rackmount	Same	$1,927
	Catalyst 2924M XL	Same	24	Two 10/100 uplink ports	Rackmount	Same	$1,614
Compex Inc. Anaheim, Calif. 714-630-7302 www.cpx.com	PS2208 Pocket Switch	Unmanaged	Eight	One shared 10/100 uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$131
D-Link Systems Inc. Irvine, Calif. 949-788-0805 www.dlink.com	DSS-8+	Unmanaged	Eight	One MDI-II uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation, VLAN support	$87
	DSS-16+	Unmanaged	16	Two MDI-II uplink ports	Desktop	Same	$297
Edimax Computer Co. Santa Clara, Calif. 408-496-1105 www.edimax.com	ES-3108P	Unmanaged	Eight	One shared 10/100 uplink port	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$149
	ES-3116R	Unmanaged	16	Same	Rackmount	Same	$395
Farallon Communications Inc. San Leandro, Calif. 510-814-5000 www.farallon.com	Fast Starlet Palm Switch	Unmanaged	Eight	N/A	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$153
	Fast Starlet Switch 16	Unmanaged	16	One 100Base-FX port	Rackmount	Same	$378
	Fast Starlet Switch 24	Unmanaged	24	Same	Rackmount	Same	$396
Garrett Communications Inc. Fremont, Calif. 510-438-9071 www.garrettcom.com	Magnum 4K8	Unmanaged	Eight	One or two optional 100Base-FX ports	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$599
	Magnum 4K16	Unmanaged	16	Same	Rackmount	Same	$899
	Magnum 4K24	Unmanaged	24	Same	Rackmount	Same	$1,199
Hewlett-Packard Co. Palo Alto, Calif. 650-857-1501 www.hp.com	ProCurve Switch 408	Unmanaged	Eight	One MDI/MDI-X port	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$229
	ProCurve Switch 1600M	SNMP, Telnet, Web-based	16	One MDI/MDI-X port	Rackmount	Same	$1,099
	ProCurve Switch 2224	Unmanaged	24	One open transceiver slot	Rackmount	Same	$529

Vendor	Product	Managed/ unmanaged	10/100-Mbps ports	Expansion	Configuration	Key switching features	Price
Hawking Technologies Inc. Irvine, Calif. 949-580-0888 www.hawkingtech.com	Model PN636ES	Unmanaged	16	Two 10/100 uplink ports	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$321
	Model PN2400ES	Unmanaged	24	Same	Rackmount	Same	$445
IBM Corp. Armonk, N.Y. 914-765-1900 www.ibm.com	8275 Series Model 318	SNMP, RMON, Web-based	16	1000Base-SX and 100Base-FX port options	Desktop, rackmount	Store-and-forward, full- and half-duplex, auto-negotiation, VLAN support	$1,425
	8275 Series Model 322	Optional	20	Same	Same	Same	$995
	8275 Series Model 326	Optional	24	Same	Same	Same	$715
Intel Corp. Santa Clara, Calif. 408-765-8080 www.intel.com	Intel Express 410T Standalone Switch	Intel Device View, SNMP, RMON, Web- based	16, 24	N/A	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$546
	Intel Express 510T Standalone Switch	Same	24	N/A	Rackmount	Same	$1,570
Kingston Technology Co. Fountain Valley, Calif. 714-435-2600 www.kingston.com	KNS800/WG	Unmanaged	Eight	UTP port 5	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$152
Lancast Inc. Nashua, N.H. 603-880-1833 www.lancast.com	CenturySwitch 3508-11 with Fiber Uplink	Unmanaged	Eight	One 100Base-FX uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$359
	CenturySwitch 3508-01	Unmanaged	Eight	N/A	Desktop	Same	$539
	CenturySwitch 3512-01	Unmanaged	12	N/A	Desktop	Same	$899
Linksys International Irvine, Calif. 949-261-1288 www.linksys.com	DSSX12	Unmanaged	12	One 100Base-FX uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$358
	DSSX16	Unmanaged	16	Same	Desktop	Same	$449
	DSSX24	Unmanaged	24	Same	Desktop	Same	$565
Lucent Technologies Inc. Murray Hill, N.J. 980-582-6500 www.lucent.com	Cajun P120 Workgroup Switch	Cajun P120 Manager with SNMP, RMON, Lucent SMON	24	Optional 10/100, 100Base-FX or 1000Base-SX/LX ports	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$1,755 GSA
Marconi Communications Corp. Warrendale, Pa. 724-742-4444 www.marconi.com	Fore ES-1000	Unmanaged	22	Two optional 1000Base-SX/LX ports	Rackmount	Store-and-forward; expansion modules for addition of up to four 10/100 ports	$2,040
Network Peripherals Inc. Milpitas, Calif. 408-321-9218 www.npix.com	NuSwitch DS12A	SNMP, RMON, Telnet, Web- based, console port	12	Optional 100Base-FX uplink port	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$1,193
	NuSwitch DS16	Same	16	One 10/100 uplink port or optional 100Base-FX port	Rackmount	Same	$1,387
Nortel Networks Corp. Brampton, Ontario 905-863-0000 www.nortelnetworks.com	BayStack 70-8T	Unmanaged	Eight	One MDI/MDI-X push-button option	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$350
	BayStack 70-16T	Unmanaged	16	Same	Desktop	Same	$595
	BayStack 70-24T	Unmanaged	24	Same	Rackmount	Same	$994
OvisLink Technologies Corp. City of Industry, Calif. 626-854-1805 www.ovislink.com	Ether-FSH8TX	Unmanaged	Eight	N/A	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$138
	Ether-FSH16TX	Unmanaged	16	N/A	Desktop	Same	$375
	Ether-FSH24TX	Unmanaged	24	N/A	Desktop	Same	$595
SMC Networks Irvine, Calif. 949-707-2400 www.smc.com	EZ Switch II Model 6308TX	Unmanaged	Eight	One 10/100 uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation, self-configuring	$140
	TigerSwitch 10/100 Model SMC6912M	SMC EliteView, SNMP, RMON	12	Two 100Base-FX ports	Rackmount	Same	$986
	TigerSwitch 10/100 Model SMC6924M	SMC EliteView, SNMP, RMON	24	Same	Rackmount	Same	$1,232
3Com Corp. Santa Clara, Calif. 408-764-4000 www.3com.com	OfficeConnect Dual Speed Switch 8	Unmanaged	Eight	One MDI/MDI-X uplink port	Desktop	Store-and-forward, full- and half-duplex, auto-negotiation	$210
	OfficeConnect Dual Speed Switch 16	Unmanaged	16	One MDI/MDI-X uplink port	Desktop	Same	$390
Trendware International Inc. Torrance, Calif. 310-891-1100 www.trendware.com	TE100-S1616	Unmanaged	16	One shared MDI-II port, optional MDA 100Base-FX port	Rackmount	Store-and-forward, full- and half-duplex, auto-negotiation	$363
	TE100-S2424	Unmanaged	24	Same	Rackmount	Same	$518
Unicom Electric Inc. Rowland Heights, Calif. 626-964-7873 www.unicomlink.com	Dyna Switch 16	Unmanaged	16	One fixed 10/100	Rackmount	Store-and-forward, full- andhalf-duplex, auto-negotiation, optional VLAN support	$349
	Smart-Switch/24	SNMP, RMON	24	One fixed 10/100	Rackmount	Same	$1,575