摘要:
A supervisory communications node monitors and controls communications with a plurality of remote devices throughout a widely distributed network. A method, system, and computer program product are provided to convey and maintain information used to synchronize the packetization and burst operations within the network. During session setup, jitter constraints indirectly are used to explicitly communicate a synchronization timing reference. The timing reference is set at the beginning of a phase/period boundary used to service the session. In an embodiment, the announcement of the first grant is used as an explicit indication of the synchronization timing reference value. In another embodiment, the synchronization timing reference value is inferred if a remote device receives contiguous voice grants meeting certain conditions. In an embodiment implementing periodic scheduling, the actual arrival of the first grant is used to infer the synchronization timing reference value. In an embodiment, the present invention enables the synchronization timing reference value and/or the periodicity to be modified if network conditions indicate that packetization and burst operations are out-of-synchronization.
摘要:
A system and method for a generalized packet header suppression mechanism is described. This mechanism is implemented via a descriptor table. An exact copy of the descriptor table is stored in both the sender and receiver of packets via a communication medium. Entries in the descriptor table provide the information necessary to both suppress and expand the headers of well-known packets. The sender of the packet uses the descriptor table to suppress the packet header prior to transmitting the packet over the communication medium. When the packet reaches the receiver, the receiver uses the descriptor table to expand or reconstruct the packet header. This procedure results in less bandwidth required to transmit well-known messages because known header data is not transmitted via the medium, thereby not wasting bandwidth. The suppression mechanism allows the complete suppression of the header of a packet (as opposed to the traditional payload suppression) by a shorter message descriptor. Thus, this mechanism allows a common framework to support several protocols in the same communication medium.
摘要:
A system and method for guaranteeing a delay jitter bound when scheduling bandwidth grants for voice calls via a communication medium is provided. The method includes the steps of: determining the delay jitter bound; based on the determined delay jitter bound, dividing a packetization frame period into phases; assigning a voice call to one of the phases; and scheduling a bandwidth grant to the voice call during the assigned phase, thereby guaranteeing the delay jitter bound. The system includes a scheduler, where the scheduler determines the delay jitter bound, divides a packetization frame period into phases based on the determined delay jitter bound, assigns a voice call to one of the phases, and schedules a bandwidth grant to the voice call during the assigned phase, thereby guaranteeing the delay jitter bound. A dejitter buffer implements a way to provide zero jitter service, even though the packet transmission on the cable network has jitter, by delaying the packet and thus converting jitter into delay.
摘要:
Classification of packets into flows is an inherent operation performed by networks that support enhanced services. To support multiple-dimensional packet classification, a packet classification system is provided to select representative bits from a packet to look up a set of rules. The per-flow classification works with a large set of rules, where each rule comprises of multiple fields and also allows fast dynamic variation in the rule set. A lookup process includes a simple and finite set of instructions that can be efficiently implemented as pipelined hardware and support very high packet arrival rates.
摘要:
A cable modem method, system, and computer program product are provided for payload header suppression in which a limited number of suppression indices is used to map suppression rules to data streams. Network resources are conserved by implementing precise classification algorithms to correctly identify incoming packets at the cable modem as belonging to a particular data stream, which ensures that a minimum number of suppression indices are utilized. Additionally, network resources are conserved by utilizing sophisticated algorithms for reusing suppression indices when new data streams are detected by the cable modem. One such reuse algorithm involves recycling the suppression index that has been least recently used in transmitting a packet with a suppressed payload header.