Product Data Sheets (pdf)...T1 WAN Access Router
10BASE-T to AUI Transceiver
Installation and User Guide (May-07)
Black Box Explains...Ethernet hubs vs. Ethernet switches.
Although hubs and switches look very similar and are connected to the network in much the same way, there is a significant difference in the way they function.
What is a... more/see it nowhub?
An Ethernet hub is the basic building block of a twisted-pair (10BASE-T or 100BASE-TX) Ethernet network. Hubs do little more than act as a physical connection. They link PCs and peripherals and enable them to communicate over a network. All data coming into the hub travels to all stations connected to the hub. Because a hub doesnt use management or addressing, it simply divides the 10- or 100-Mbps bandwidth among users. If two stations are transferring high volumes of data between them, the network performance of all stations on that hub will suffer. Hubs are good choices for small- or home-office networks, particularly if bandwidth concerns are minimal.
What is a switch?
An Ethernet switch, on the other hand, provides a central connection in an Ethernet network in which each connected device has its own dedicated link with full bandwidth. Switches divide LAN data into smaller, easier-to-manage segments and send data only to the PCs it needs to reach. They allot a full 10 or 100 Mbps to each user with addressing and management features. As a result, every port on the switch represents a dedicated 10- or 100-Mbps pathway. Because users connected to a switch do not have to share bandwidth, a switch offers relief from the network congestion a shared hub can cause.
What to consider when selecting an Ethernet hub:
• Stackability. Select a stackable hub connected with a special cable so you can start with one hub and add others as you need more ports. The entire stack functions as one device.
• Manageability. Choose an SNMP-manageable hub if you have a large, managed network.
What to consider when selecting an Ethernet switch:
• Manageability. Ethernet switches intended for large managed networks feature built-in management, usually SNMP.
• OSI Layer operation. Most Ethernet switches operate at “Layer 2,” which is for the physical network addresses (MAC addresses). Layer 3 switches use network addresses, and incorporate routing functions to actively calculate the best way to send a packet to its destination. Very advanced Ethernet switches, often known as routing switches, operate on OSI Layer 4 and route network traffic according to the application.
• Modular construction. A modular switch enables you to populate a chassis with modules of different speeds and media types. Because you can easily change modules, the modular switch is an adaptable solution for large, growing networks.
• Stackability. Some Ethernet switches can be connected to form a stack of two or more switches that functions as a single network device. This enables you to start with fewer ports and add them as your network grows. collapse
Product Data Sheets (pdf)...Local Repeaters/Remote Fiber Optic Repeaters
Product Data Sheets (pdf)...2-Port Hub
Product Data Sheets (pdf)...4-Port BNC Repeater
Dual-Speed Personal MiniHubs with Fiber Ports
Installation and User Guide (May-04)
Black Box Explains...Using repeaters to extend your network.
A repeater is a signal regenerator. It amplifies and regenerates received data and relays data from one length of cable to another—this can be between two segments of the same... more/see it nowcable type (such as UTP to UTP) or between two lengths of entirely different cable types (such as UTP to ThinNet). Because repeaters operate at the Data Link layer of the OSI model, having too many repeaters on a network introduces delays and causes problems with signal timing. Ethernet allows a maximum of two IRLs (InterRepeater Links) between any two devices and up to four per network. A hub also counts as a repeater. (If simple media conversion is your goal, use media converters instead. For details, contact Tech Suport.)
Repeaters boost distance by amplifying the signal.
A repeater actually regenerates and amplifies the signal to gain distance. The repeater not only changes the media type, it also gives the signal a boost to send it over a longer distance.
Repeaters boost distance through a change in media.
In addition to amplifying the signal, a repeater can also add distance to your network by enabling you to change to a media type such as fiber that supports longer distances. collapse
Black Box Explains... Bridges
If you work with legacy networks, you have doubtlessly encountered bridges. Bridges perform the same function as today’s switches in that they connect multiple network segments to create one homogenous... more/see it nownetwork, while keeping each segment isolated from the others.
Bridges operate on MAC-layer addresses and are protocol independent, so they transfer data between workstations without understanding the protocol. Since they don’t have to understand the protocol, they require little or no configuration.
Once you connect the bridge to the network, it automatically learns the addresses of all connected nodes and then creates an internal address table of this information.
When the bridge sees a packet, it checks the packet’s destination address against its internal list. If the address indicates the packet needs to be forwarded, the bridge passes the packet to the appropriate segment. If a bridge doesn’t know where a packet belongs—for example, when a station is first powered on—it passes on the packet.
Bridges can also distinguish between local data and remote data, so data traveling from one workstation to another in the same network doesn’t have to cross the bridge.
Although they are no longer in general use, Black Box stocks bridges for use as replacement parts in legacy networks. Replacing bridges with bridges rather than switches is often preferable because bridges are generally available with the BNC and AUI interfaces often found in older networks. Also, some bridges are able to link to other protocols such as RS-530 and X.21, enabling you to use these media to establish Ethernet network connections.