US 6,603,766 B1Granted

Apparatus and method for implementing an ATM AAL2 combined use timer

AssigneeMotorola, Inc.

InventorsDovrat Zifroni, Eran Kirzner, Avi Hagai

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Abstract

A system and a method of the present invention for implementing a combined use Timer_CU within an ATM transmitter. The ATM transmitter being able to handle a plurality of ATM channels, at least one of the channel being an ATM AAL2 channel. The ATM channels can provide ATM-cells at different traffic parameters, such as, for example, different cell or bit rate, priorities, and bursts. The system schedules channels in a first table by channel identifiers. Cyclical pointers to this first table advance (i) at every time slot, (ii) within a time slot, whereas (iii) CPS-Packets with one or more octets already packed wait at most the duration of a Timer_CU before being scheduled to be sent by CPS transmitter to ATM transmitter. Conveniently, the schedule scheme is based upon a scheduling table comprising of a plurality of time slots. CPS-Packets are multiplexed and packed to form a CPS_PDU, the CPS_PDU is submitted to a processor that handles the transmission of ATM cells, each CPS_PDU is converted to an ATM cell and transmitted to a communication channel during a single time slot. Therefore, Timer_CU ends when the ATM cell actually is transmitted.

Claims23

Dependent claims

A method for implementing an ATM AAL2 combined use timer in an apparatus that is adapted to receive cells from channels and periodically in one time slot transmitting up to Nslot cells to a communication line, at least one channel is an ATM AAL2 channel, the method comprising the steps of:

(a) assigning a first pointer R and a second pointer V to schedule fields;
and
(b) in a time slot identified by said first pointer R,
(One) assigning a counter to N to Nslot;
(Two) looking up in the schedule fields identified by said second pointer V for channel identifiers “s” and if “s” is found checking if a channel identified by the “s” is an ATM AAL2 channel,
(1) if a channel identified by the “s” is an ATM AAL2 channel, performing the sub-steps of:
(1st) reading a CPS-PDU(s) from a channel memory, and if there are CPS-packets to be multiplexed and packed into CPS-PDU(s) then multiplexing and packing the CPS-Packets into the CPS-PDU(s);
(2nd) checking if the CPS-PDU(s) is full;
(1) if CPS-PDU(s) is full, converting CPS-PDU(s) to an ATM cell ATM(s) and jumping to a step of transmitting a cell from one channel identified by“s”;
(2) if CPS-PDU(s) is not full, checking if period Timer_CU(s) expires during the time slot identified by R;
(a) if the answer is “yes” filling CPS-PDU(s) with PAD octets, converting CPS-PDU(s) to an ATM(s), resetting a measurement of Timer_CU(s) and jumping to a step of transmitting a cell from one channel identified by “s”;
(b) if the answer is “no”, storing the CPS-PDU(s) in a channel memory, to be retrieved the next time “s” appears in the schedule fields, starting a measurement of Timer_CU(s) and jumping to step of moving channel identified “s” to a different schedule field;
(2) if a channel identified by the “s” is not an ATM AAL2 channel, checking it the channel identified by “s” is able to provide cells during the time slot identified by R and if the answer is “no” jumping to step of looking up in the schedule fields identified by said second pointer V for channel identifiers “s”;
transmitting a cell from one channel identified by “s”, moving said channel identifier “s” to a different schedule field identified by J, and changing said counter N;
(c) repeating step 1(b) until N>Nslot and when N>Nslot changing said first pointer R and starting said step (ii) for a new time slot;
and
(d) changing said second pointer V and repeating step 1(b) if said second pointer V and said first pointer R are different.

14 more elements

(Nine) assigning a first pointer R and a second pointer V to schedule fields;
and
(b) in a time slot identified by said first pointer R,
(One) assigning a counter N to Nslot;
(Two) looking up in the schedule fields identified by said second pointer V for channel identifiers “s” and if “s” is found checking if a channel identified by the “s” is an ATM AAL2 channel,
(2) if a channel identified by the “s” is an ATM AAL2 channel, performing the sub-steps of:
(A) reading a CPS-PDU(s) from a channel memory, and if there are CPS-packets to be multiplexed and packed into CPS-PDU(s) then multiplexing and packing the CPS-Packets into the CPS-PDU(s);
(2nd) checking if the CPS-PDU(s) is full;
(1) if CPS-PDU(s) is full, converting CPS-PDU(s) to an ATM cell ATM(s) and jumping to a step of transmitting a cell from one channel identified by “s”;
if a portion of a CPS-packet is packed into CPS-PDU(s) and a remaining portion of the CPS-packet is to be packed into a next CPS-PDU(s) then starting to measure a period Timer_CU(s);
(2) if CPS-PDU(s) is not full, checking if period Timer_CU(s) expires during the time slot identified by R;
(a) if the answer is “yes” filling CPS-PDU(s) with PAD octets, converting CPS-PDU(s) to an ATM(s), resetting a measurement of Timer_CU(s) and jumping to a step of transmitting a cell from one channel identified by “s”;
(b) if the answer is “no”, storing the CPS-PDU(s) in a channel memory, to be retrieved the next time “s” appears in the schedule fields, starting a measurement of Timer_CU(s) and jumping to step of moving channel identified “s” to a different schedule field;
(2) if a channel identified by the “s” is not an ATM AAL2 channel, checking it the channel identified by “s” is able to provide cells during the time slot identified by R and if the answer is “no” jumping to step of looking up in the schedule fields identified by said second pointer V for channel identifiers “s”;
transmitting a cell from one channel identified by “s”, moving said channel identifier “s” to a different schedule field identified by J, and changing said counter N;
(c) repeating step 1(b) until N>Nslot and when N>Nslot changing said first pointer R and starting said step (ii) for a new time slot;
and
(d) changing said second pointer V and repeating step 1(b) if said second pointer V and said first pointer R are different.

15 more elements

A system having an ATM AAL2 common use Timer_CU, the system is adapted to receive cells and CPS-packets from channels and periodically in one time slot transmit up to Nslot cells to a communication line, at least one channel is an ATM AAL2 channel, the system comprising:

a packing and multiplexing unit, adapted to receive a plurality of CPS-Packets, multiplex and pack the plurality of CPS-packets to a plurality of CPS-PDUs;
a processor adapted to control the multiplexing and packing unit and adapted to transfer data cells from a plurality of channels to at least one data output;
a first table coupled to said processor for storing channel identifiers to schedule one of the following operations, for a finite number of time slots:
(a) (i) data transfer;
(b) (ii) multiplexing and packing of at least a portion of a CPS packet to a CPS-PDS;
(c) (iii) multiplexing and packing of at least a portion of a CPS packet to a CPS-PDS, and performing a data transfer;
wherein in the first table a sub-table defined by a first pointer R and a second pointer V is adapted to store channel identifiers indicating a location of data to be either transferred, packed and multiplexed, packed and multiplexed and transferred;
a second table coupled to said processor for storing parameters of channels identified by the channel identifiers;
wherein the processor cyclically
(One) checks the sub table and if a channel identifier is found in the sub-table,
(1) performs, either by itself or in conjunction with the multiplexing and packing unit, at least one operations (i)-(iii);
(2) reschedules a next operation out of operations (i)-(iii) according to the parameters from the second table and if a Timer_CU period is measured, also according to an expiration of the Timer_CU period;
(b) changes V to modify the sub-table and repeating step (a) until V and R are identical;
(Three) generates idle cells for filling up;
and
(Four) modifies R and repeats steps (a)-(c).

13 more elements

A system comprising:

a channel memory adapted to store and provide CPS-packets of ATM AAL2 channels and to store and provide cells from other type of channels;
the channel memory is adapted to store data, either in a cell form or in a CPS-packet form of S channels.
a multiplexing and packing unit, coupled to the channel memory, adapted to receive a plurality of CPS-packets and to pack and multiplex the plurality of CPS packets to a plurality of CPS-PDU:
a program memory adapted to store a code to be executed by a processor, the code has a time slot pointer R and an auxiliary pointer V;
a processor, coupled to the program memory, the processor is adapted to (i) control a multiplexing and packing operation of the multiplexing and packing unit, (ii) transfer data cells, (iii) control a multiplexing and packing of the multiplexing and packing unit, receive a CPS-PDU, convert a CPS-PDU to an ATM cell and to transfer the ATM cell;
wherein the processor is adapted to handle up to Nslot operations such as (i)-(iii) during a time slot identified by R;
a first plurality of S first fields for storing a period P(s) and a plurality of parameters for each the channel CH(s) of the S channels;
a second plurality of S second fields for storing link entries L(s) in some of the second fields;
a third plurality of M third fields for storing channel identifiers of CH(s), said third fields;
wherein during one time slot identified by R, R points to one of the third fields and V points to one or consecutively to more than one of the third fields;
wherein during one time slot said processor performs up to Nslot times
(a) looking up in at least one of the third fields, and if channel identifiers are stored in that third field, performs, either by itself or in conjunction with the multiplexing and packing unit, at least one operations (i)-(iii);
and
(b) reschedules a next operation out of operations (i)-(iii) according the parameters of a channel CH(s) and if a Timer_CU(s) period is measured, also according to an expiration of the Timer_CU(s) period.

11 more elements

Dependencies are inferred from the claim text.