Specifications

Glossary
GL-7
Cisco ONS 15454 Installation and Operations Guide, R3.2
March 2002
Link budget
The difference between the output power and receiver power of an optical signal expressed in dB. Link refers to an optical
connection and all of its component parts (optical transmitters, repeaters, receivers, and cables).
Link integrity
The network communications channel is intact.
Loopback test
Test that sends signals then directs them back toward their source from some point along the communications path. Loopback
tests are often used to test network interface usability.
LOW
Local Orderwire. A communications circuit between a technical control center and selected terminal or repeater locations.
M
MAC address
Standardized data link layer address that is required for every port or device that connects to a LAN. Other devices in the
network use these addresses to locate specific ports in the network and to create and update routing tables and data structures.
MAC addresses are six bytes long and are controlled by the IEEE. Also known as the hardware address, MAC-layer address,
and physical address.
Maintenance user
A security level that limits user access to maintenance options only. See also Superuser, Provisioning User, and Retrieve User.
Managed device
A network node that contains an SNMP agent and resides on a managed network. Managed devices include routers, access
servers, switches, bridges, hubs, computer hosts, and printers.
Managed object
In network management, a network device that can be managed by a network management protocol. Sometimes called an MIB
object.
Mapping
A logical association between one set of values, such as addresses on one network, with quantities or values of another set,
such as devices on another network.
MIB
Management Information Base. Database of network management information that is used and maintained by a network
management protocol such as SNMP or CMIP. The value of a MIB object can be changed or retrieved using SNMP or CMIP
commands, usually through a GUI network management system. MIB objects are organized in a tree structure that includes
public (standard) and private (proprietary) branches.
Multicast
Single packets copied by the network and sent to a specific subset of network addresses.