MT90222 ZARLINK [Zarlink Semiconductor Inc], MT90222 Datasheet - Page 151

• Manufacturer Part Number: MT90222
• Description: 4/8/16 Port IMA/TC PHY Device
• Manufacturer: ZARLINK [Zarlink Semiconductor Inc]

MT90222/3/4
Data Sheet
Cell - Fixed-size information package consisting of 53 bytes (octets) of data; of these, 5 bytes represent the cell
header and 48 bytes carry the user payload and required overhead.
Cell Delay Variation (CDV) - a QoS parameter that measures the peak-to-peak cell delay through the network; re-
sults from buffering and cell scheduling.
Common Transmit Clock (CTC) Configuration - This is a configuration where the transmit clocks of all links within
the IMA group are derived from the same clock source.
Constant Bit Rate - An ATM service category supporting a constant or guaranteed rate, with timing control and strict
performance parameters. Used for services such as voice, video, or circuit emulation.
Filler Cell - A Filler Cell is used to fill in the IMA frame when no cells are available at the ATM layer. It is used for
performing cell rate decoupling at the IMA sublayer (e.g., similar to the Idle Cell used in single link interfaces).
Header Error Control (HEC) - ATM equipment (usually the PHY) uses the fifth octet in the ATM cell header to check
for an error and correct the contents of the header; CRC algorithm allows for single-error correction and multiple-er-
ror detection.
I.363 - ITU-T Recommendation specifying the AALs for B-ISDN.
IMA Frame - The IMA Frame is used as the unit of control in the IMA protocol. It is defined as M consecutive cells,
on each of N links, where 1 ≤ N ≤ 32 (determined by the UM and IMA link start-up procedure), in an IMA Group. One
of the M cells on each of the N links is an ICP cell that occurs within the frame at the ICP cell offset position. This
offset position may be different between links. The IMA Frame is Aligned on all links. Differential link delay can cause
the reception to be ‘mis-aligned‘ in time. Alignment can be recovered using a link delay synchronization mechanism.
The ICP ‘Stuff‘ mechanism is a controlled violation of the IMA consecutive frame definition.
IMA Group - The IMA Group is a ‘group‘ of links at one end of a ’circuit’ that establish an IMA virtual link to another
end.
IMA Sublayer - The IMA Sublayer is part of the Physical Layer that is located between the interface specific Trans-
mission Convergence Sublayer and the ATM Layer.
IMA Virtual Link - The IMA Virtual Link is a virtual circuit established between two IMA ends over a number of Phys-
ical Links (i.e., IMA Group).
Inhibiting - Inhibiting is a voluntary action that disables the capacity of a group or link to carry ATM Layer cells for
reasons other than reported problems.
Insufficient Links - This is a Group State indicating that the group does not have sufficient links to be in the Oper-
ational State.
Independent Transmit Clock (ITC) Configuration - This is a configuration where the transmit clock of at least one
link within the IMA Group is not derived from a common clock source.
Isochronous - The temporal property of an event or signal recurring at known periodic time intervals (e.g., 125 µs).
Isochronous signals are dependent on some uniform timing, or carry their own timing information embedded as part
of the signal. Examples are DS-1/T1 and E1. From the root words, “iso” meaning equal, and “chronous” meaning
time.
ITU-T - International Telecommunications Union Telecommunications Standards Sector.
Layer Management Functions - The Layer Management Functions relate to processing of actions such as config-
uration, fault monitoring and performance monitoring within the group.
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