Справочник Пользователя для Netopia 4753 2a4na
2 Administration Guide
community strings: Sequences of characters that ser ve much like passwords for devices using SNMP.
Different community strings may be used to allow an SNMP user to gather device information or change device
configurations.
Different community strings may be used to allow an SNMP user to gather device information or change device
configurations.
CRC (Cyclic Redundancy Check): A computational means to ensure the integrity of a block of data. The
mathematical function is computed, before the data is transmitted at the originating device. Its numerical value
is computed based on the content of the data. This value is compared with a recomputed value of the function
at the destination device.
mathematical function is computed, before the data is transmitted at the originating device. Its numerical value
is computed based on the content of the data. This value is compared with a recomputed value of the function
at the destination device.
DCE (Data Communications Equipment): Term defined by standards committees that applies to
communications equipment, typically modems or printers, as distinct from other devices that attach to the
network, typically personal computers or data terminals (DTE). The distinction generally refers to which pins in
an RS-232-C connection transmit or receive data. Also see DTE.
communications equipment, typically modems or printers, as distinct from other devices that attach to the
network, typically personal computers or data terminals (DTE). The distinction generally refers to which pins in
an RS-232-C connection transmit or receive data. Also see DTE.
DHCP (Dynamic Host Configuration Protocol): A ser vice that lets clients on a LAN request configuration
information, such as IP host addresses, from a ser ver.
information, such as IP host addresses, from a ser ver.
DNS (Domain Name Service): A TCP/IP protocol for discovering and maintaining network resource information
distributed among different ser vers.
distributed among different ser vers.
download: The process of transferring a file from a ser ver to a client.
DTE (Data Terminal Equipment): Term defined by standards committees, that applies to communications
equipment, typically personal computers or data terminals, as distinct from other devices that attach to the
network, typically modems or printers (DCE). The distinction generally refers to which pins in an RS-232-C
connection transmit or receive data. Pins 2 and 3 are reversed. Also see DCE.
equipment, typically personal computers or data terminals, as distinct from other devices that attach to the
network, typically modems or printers (DCE). The distinction generally refers to which pins in an RS-232-C
connection transmit or receive data. Pins 2 and 3 are reversed. Also see DCE.
EIA (Electronic Industry Association): A Nor th American standards association.
Ethernet: A networking protocol that defines a type of LAN characterized by a 10 Mbps (megabits per second)
data rate. Ethernet is used in many mainframe, PC, and UNIX networks, as well as for EtherTalk.
data rate. Ethernet is used in many mainframe, PC, and UNIX networks, as well as for EtherTalk.
Ethernet address: Sometimes referred to as a hardware address. A 48-bits long number assigned to ever y
Ethernet hardware device. Ethernet addresses are usually expressed as 12-character hexadecimal numbers,
where each hexadecimal character (0 through F) represents four binar y bits. Do not confuse the Ethernet
address of a device with its network address.
Ethernet hardware device. Ethernet addresses are usually expressed as 12-character hexadecimal numbers,
where each hexadecimal character (0 through F) represents four binar y bits. Do not confuse the Ethernet
address of a device with its network address.
firmware: System software stored in a device’s memor y that controls the device. The Netopia 4753’s
firmware can be updated.
firmware can be updated.
gateway: A device that connects two or more networks that use different protocols. Gateways provide address
translation ser vices, but do not translate data. Gateways must be used in conjunction with special software
packages that allow computers to use networking protocols not originally designed for them.
translation ser vices, but do not translate data. Gateways must be used in conjunction with special software
packages that allow computers to use networking protocols not originally designed for them.
HDLC (High-Level Data Link Control): A generic link-level communications protocol developed by the
International Organization for Standardization (ISO). HDLC manages synchronous, code-transparent, serial
information transfer over a link connection. See also SDLC (Synchronous Data Link Control).
International Organization for Standardization (ISO). HDLC manages synchronous, code-transparent, serial
information transfer over a link connection. See also SDLC (Synchronous Data Link Control).
header: In packets, a header is par t of the envelope information that surrounds the actual data being
transmitted. In e-mail, a header is usually the address and routing information found at the top of messages.
transmitted. In e-mail, a header is usually the address and routing information found at the top of messages.
hop: A single traverse from one node to another on a LAN.
hop count: The number of nodes (routers or other devices) a packet has gone through. If there are six routers
between source and destination nodes, the hop count for the packet will be six when it arrives at its destination
node. The maximum allowable hop count is usually 15.
between source and destination nodes, the hop count for the packet will be six when it arrives at its destination
node. The maximum allowable hop count is usually 15.
host: A single, addressable device on a network. Computers, networked printers, and routers are hosts.