T8207 Datasheet, PDF (12/158 Pages) Agere Systems – ATM Interconnect

CelXpres T8207
ATM Interconnect
Advance Data Sheet
September 2001
1 Product Overview (continued)
1.5 Glossary
Bus Cell:
Major content of the cell bus frame consisting of
56 bytes, 4 bytes for routing options and 52 bytes
for the ATM cell content, which excludes the HEC.
The bus cell is preceded by the 4 bytes of request and
followed by the 4 bytes of grant and parity information.
CLP:
Cell loss priority. The CLP is a 1-bit field in the cell
header that becomes set when the cell violates the
negotiated quality of service parameters.
EFCI:
Explicit forward congestion indication. The EFCI is a
1-bit field in the PTI field of the cell header that
becomes set when the cell encounters congestion.
FECN:
Forward explicit congestion notification. FECN is a
method used by the network to signal to the destination
when congestion is encountered. The EFCI bit is used
to indicate the congestion.
GFC:
Generic flow control. The GFC is a 4-bit field in the cell
header that may be used by a UNI to support traffic and
congestion control. Typically, this field is programmed
to “0000” indicating that generic flow control is not sup-
ported. GFC may be used in priority protocols.
Grant Section:
Last 4 bytes of the cell bus frame. The grant section
occurs during the last clock cycle of the cell bus frame.
During this cycle, the cell bus arbiter indicates which
T8207 may transmit during the next bus cell unit of the
cell bus frame. A parity vector is also transmitted during
the grant section.
HEC:
Header error control. The HEC is a 1-byte field in the
cell header used for bit error detection and correction in
the header.
NNI:
Network node interface. The NNI is the interface
between nodes in the public network.
OAM Cell:
Operations and maintenance cell. An OAM cell carries
local management information.
PPD:
Partial packet discard. PPD is a technique to relieve
congestion. When one cell in a packet is lost, all
remaining cells in the packet, except the last, are dis-
carded.
PTI:
Payload type identifier. The PTI is a 3-bit field in the cell
header containing information about the type of data
(user, OAM, or traffic management) and about encoun-
tered congestion.
QoS:
Quality of service. Quality of service parameters define
the performance requirements and characteristics for
traffic on an assigned channel. Some parameters
include cell loss ratio, cell transfer delay, cell delay vari-
ation, peak cell rate, and sustained cell rate.
RM:
Resource management. RM is the local management
of network resources.
RxCLAV:
Receive cell available signal as described in the ATM
Forum’s universal test and operations PHY interface
for ATM (UTOPIA) Level 1, Version 2.01 and Level 2,
Version 1.0 specifications.
RxENB:
Receive enable signal as described in the ATM
Forum’s universal test and operations PHY interface
for ATM (UTOPIA) Level 1, Version 2.01 and Level 2,
Version 1.0 specifications.
TxCLAV:
Transmit cell available signal as described in the ATM
Forum’s universal test and operations PHY interface
for ATM (UTOPIA) Level 1, Version 2.01 and Level 2,
Version 1.0 specifications.
TxENB:
Transmit enable signal as described in the ATM
Forum’s universal test and operations PHY interface
for ATM (UTOPIA) Level 1, Version 2.01 and Level 2,
Version 1.0 specifications.
UNI:
User network interface. The UNI is the interface
between a private network node and a public network
node.
VCI:
Virtual channel identifier. The VCI is a 2-byte field in the
cell header that identifies the virtual channel used by
the cell.
VPI:
Virtual path identifier. The VPI is an 8-bit field in the
UNI cell header or a 12-bit field in the NNI cell header
that identifies the virtual path of the cell.
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