Method and apparatus for converting between byte lengths and burdened burst lengths in a high speed modem
First Claim
1. A method for transmitting data packets in a cable modem system, comprising:
- receiving a set of parameters relating to a physical layer of the cable modem system;
calculating a set of byte length values corresponding to respective physical length values in response to receiving said set of parameters;
storing said calculated set of byte length values in a lookup table;
retrieving a first physical length value by accessing said lookup table, said first physical length value corresponding to a first byte length value of a data packet to be transmitted over said physical layer of the cable modem system;
transmitting a request message including said first physical length value;
receiving a grant message including a second physical length value;
retrieving a second byte length value corresponding to said second physical length value by accessing said lookup table, said second byte length value for determining a fragment size for transmitting a fragment of said data packet over said physical layer of the cable modem system.
4 Assignments
0 Petitions
Accused Products
Abstract
Requests are processed to transmit data packets upstream from a cable modem to a cable headend in a manner that minimizes the use of CPU operations and/or memory capacity. Data packets to be transmitted upstream are stored at the cable modem. The data packets each have a given transmission data byte length value. Burst profiles are received successively at the cable modem. Each time a new bust profile is received, a set of physical data length values corresponding to respective transmission data byte length values is calculated from the parameters of the received burst profile. The calculated set of physical data length values is stored in memory so the individual values can be retrieved from the transmission data byte length values again and again, rather than being re-calculated each time a conversion is made from transmission data byte length values to physical data length values. The same set of physical data length values is used until a new burst profile is received by the cable modem.
26 Citations
20 Claims
-
1. A method for transmitting data packets in a cable modem system, comprising:
-
receiving a set of parameters relating to a physical layer of the cable modem system;
calculating a set of byte length values corresponding to respective physical length values in response to receiving said set of parameters;
storing said calculated set of byte length values in a lookup table;
retrieving a first physical length value by accessing said lookup table, said first physical length value corresponding to a first byte length value of a data packet to be transmitted over said physical layer of the cable modem system;
transmitting a request message including said first physical length value;
receiving a grant message including a second physical length value;
retrieving a second byte length value corresponding to said second physical length value by accessing said lookup table, said second byte length value for determining a fragment size for transmitting a fragment of said data packet over said physical layer of the cable modem system. - View Dependent Claims (2, 3, 4, 5, 6)
replacing said calculated set of byte length values in said lookup table with a new calculated set of byte length values when a new set of parameters relating to said physical layer of the cable modem system is received.
-
-
6. The method of claim 2, further comprising:
-
subtracting said second byte length value from said first byte length value to determine a difference byte length value;
retrieving a third physical length value corresponding to said difference byte length value by accessing said lookup table; and
transmitting said third physical length value with said fragment of said data packet.
-
-
7. A device for transmitting data packets in a cable modem system comprising:
-
a central processing unit (CPU) configured to calculate a set of byte length values corresponding to respective physical length values in response to receipt by the device of a set of parameters relating to a physical layer of the cable modem system;
a memory, wherein said CPU is configured to store said calculated set of byte length values in a lookup table in said memory; and
hardware adapted to access said lookup table to retrieve a physical length value corresponding to a given byte length value and to retrieve a byte length value corresponding to a given physical length value;
wherein said hardware retrieves a first physical length value for inclusion in a request message, said first physical length value corresponding to a first byte length value of a data packet to be transmitted from the device, and wherein said hardware retrieves a second byte length value for determining a fragment size for transmitting a fragment of said data packet from the device, said second byte length value corresponding to a second physical length value included in a grant message received by the device. - View Dependent Claims (8, 9, 10, 11, 12, 13)
-
-
14. A device for transmitting data packets in a cable modem system comprising:
-
means for calculating a set of byte length values corresponding to respective physical length values in response to receipt by the device of a set of parameters relating to a physical layer of the cable modem system;
a memory comprising a lookup table for storing said calculated set of byte length values; and
processing means for accessing said lookup table to retrieve a physical length value corresponding to a given byte length value and to retrieve a byte length value corresponding to a given physical length value;
wherein said processing means comprises means for retrieving a first physical length value for inclusion in a request message, said first physical length value corresponding to a first byte length value of a data packet to be transmitted from the device, and wherein said processing means comprises means for retrieving a second byte length value for determining a fragment size for transmitting a fragment of said data packet from the device, said second byte length value corresponding to a second physical length value included in a grant message received by the device. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
Specification