Specifications

Glossary
GL-9
Cisco ONS 15454 Troubleshooting and Maintenance Guide
November 2001
Path layer
The segment between the originating equipment and the terminating equipment. This path segment may encompass several
consecutive line segments or segments between two SONET devices.
Payload
Portion of a cell, frame, or packet that contains upper-layer information (data).
Ping
Packet internet grouper. ICMP echo message and its reply. Often used in IP networks to test the reachability of a network
device.
PPMN
Path Protected Mesh Network. PPMN extends the protection scheme of a unidirectional path switched ring (UPSR) beyond the
basic ring configuration to the meshed architecture of several interconnecting rings.
Priority queuing
Routing feature that divides data packets into two queues: one low-priority and one high-priority.
Provisioning user
A security level that allows the user to access only provisioning and maintenance options in CTC. See also Superuser,
Maintenance user, and Retrieve user.
Q
Queue
In routing, a backlog of packets waiting to be forwarded over a router interface.
R
Red band
DWDM wavelengths are broken into two distinct bands: red and blue. The red band is the higher frequency band. The red band
DWDM cards for the ONS 15454 operate on wavelengths between 1547.72nm and 1560.61nm.
Retrieve user
A security level that allows the user to retrieve and view CTC information but not set or modify parameters. See also Superuser,
Maintenance user, and Provisioning user.
Revertive switching
A process that sends electrical interfaces back to the original working card after the card comes back online.
Rising threshold
The number of occurrences (collisions) that must be exceeded to trigger an event.