Data center switching – The point of aggregation within a corporate network where a
switch provides high-performance access to server farms, a high-speed backbone connection,
and a control point for network management and security.
Ethe rnet – A LAN specification developed jointly by Xerox, Intel, and Digital Equipment
Corporation. Ethernet networks operate at 10Mbps using CSMA/CD to run over cabling.
Fast Etherne t – 100Mbps technology based on the Ethernet/CD network access method.
Flow Control – (IEEE 802.3z) A means of holding packets back at the transmit port of the
connected end station. Prevents packet loss at a congested switch port.
Forwarding – The process of sending a packet toward its destination by an internetworking
device.
Full-duplex – A system that allows packets to be transmitted and received at the same time
and, in effect, doubles the potential throughput of a link.
Half-duplex – A system that allows packets to be transmitted and received, but not at the
same time. Contrast with full-duplex.
IP address – Internet Protocol address. A unique identifier for a device attached to a network
using T CP/IP. The address is written as four octets separated with full-stops (periods), and is
made up of a network section, an optional subnet section and a host section.
IPX – Internetwork Packet Exchange. A protocol allowing communication in a NetWare
network.
LAN – Local Area Network. A network of connected computing resources (such as PCs,
printers, servers) covering a relatively small geographic area (usually not larger than a floor
or building). Characterized by high data rates and low error rates.
Latency – The delay between the time a device receives a packet and the time the packet is
forwarded out of the destination port.
Line speed – See baud rate.
main port – The port in a resilient link that carries data traffic in normal operating
conditions.
MDI – Medium Dependent Interface. An Ethernet port connection where the transmitter of
one device is connected to the receiver of another device.
MDI-X – Medium Dependent Interface Cross-over. An Ethernet port connection where the
internal transmit and receive lines are crossed.
MIB – Management Information Base. Stores a device's management characteristics and
parameters. MIBs are used by the Simple Network Management Protocol (SNMP) to contain
attributes of their managed systems. The Switch contains its own internal MIB.
Multicast – Single packets copied to a specific subset of network addresses. These addresses
are specified in the destination-address field of the packet.
Protocol – A set of rules for communication between devices on a network. The rules dictate
format, timing, sequencing, and error control.
Re silient link – A pair of ports that can be configured so that one will take over data
transmission should the other fail. See also main port and standby port.
RJ-45 – Standard 8-wire connectors for IEEE 802.3 10BASE-T networks.
RMO N – Remote Monitoring. Subset of SNMP MIB II, which allows monitoring and
management capabilities by addressing up to ten different groups of information.
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