S/UNI®-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
1
Definitions
This table defines the acronyms used in this data sheet.
Acronym
AIS
Definition
Alarm Indication Signal. AIS cells are OAM Fault Management cells whose Function
Type fields identify them as AIS cells as per ITU-T I.610. They are sent once per second
by an ATM Network Element which has detected certain error conditions, such as a loss
of continuity. AIS alarm refers to the detection that the S/UNI-ATLAS-3200 is receiving
AIS cells on a particular VC.
Burst Tolerance. The burst tolerance is a policing parameter that indicates the maximum
length of a burst (at the peak allowable cell rate) that is permitted before the Sustained
Cell Rate test will be violated.
BT
Backwards Performance Management Cell. These PM OAM cells are sent by a PM
session on reception of a Fwd PM cell, and carry data about the cell flow as observed by
both the start and end point of the PM flow.
Bwd PM
Bwd LB
CBR
Backwards, or Returned Loopback Cell. An OAM Loopback cell whose Loopback
Indication bit is zero, indicating it has already been looped back.
Constant Bit Rate. CBR service is one of the standard traffic contracts, in which a
constant, unchanging amount of bandwidth is guaranteed to the user, with time-of-delivery
guarantees. Voice traffic is a classic use of CBR service
CDV
CLP
Cell Delay Variation. The CDV Tolerance is one of the parameters that determines the
policing parameters, particularly the Limit parameter of the Peak Cell Rate test.
Cell Loss Priority. This is a field in the header of an OAM cell. High-priority cells are
those with CLP = 0, and are sometimes referred to as CLP0 cells. Low priority blocks are
sometimes referred to as CLP1 cells, and the aggregate flow is referred to as CLP0+1.
Continuity Check. CC cells are OAM Fault Management cells whose Function Type
fields identfy them as CC cells as per ITU-T I.610. They are sent once per second by a
flow start point in the absence of user traffic, to indicate that the connection remains
active. CC alarm refers to the detection that a VC on the S/UNI-ATLAS-3200 has
received neither user cells nor CC cells for a nominal period of 3 seconds.
The F4 OAM Layer is the OAM Layer associated with the Virtual Path. In S/UNI-ATLAS-
3200, a VC may be part of an F4 flow or an F5 flow. In the case of an F4 flow being
sourced or terminated, a number of VCs which form part of F5 flows may have an
associated F4 OAM VC, which performs the OAM for the F4 flow. This F4 OAM VC is
specified by the VPC Pointer in the Linkage Table.
CC
F4
F5
The F5 OAM Layer is the OAM Layer associated with the Virtual Channel.
Fault Management. Fault Management OAM cells include AIS cells, RDI cells, CC cells,
FM
and LB cells.
A Forward, or Parent, Loopback cell. An OAM Loopback cell whose Loopback
Fwd LB
Fwd PM
Indication bit is 1, indicating it has not yet been looped back.
Forward Performance Management cell. These PM OAM cells are sent by a PM
session at an OAM start point every N cells, where N is a programmable number ranging
from 128 to 32K. They contain information about the cell flow on a VC as seen by the
transmitting point.
GCRA
Generic Cell Rate Algorithm. The GCRA is the “Leaky Bucket” policing algorithm
described in ITU-T I.371.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
22
PMC [ PMC-SIERRA, INC ]
