Method and system for buffer occupancy reduction in packet switch network

In a packet switch network having an isochronous connection established through a first node and a second node such that a stream of packets is delivered from the first node to the second node at a nearly constant packet rate, 1/T.sub.frame, and packet phase, a method for reducing buffer occupancy time of packets delivered to the second node without affecting the nearly constant packet rated 1/T.sub.frame, said method comprising the steps of:

• (a) monitoring buffer occupancy time at the second node of a current packet of the stream of packets delivered from the first node to the second node;
• (b) generating at the second node a feedback message representative of the buffer occupancy time monitored in said step (a);
• (c) sending the feedback message back along the isochronous connection from the second node to the first node;
• and
• (d) adjusting at the first node the packet phase of subsequent packets of the stream of packets relative to the nearly constant packet rate 1/T.sub.frame without effecting the nearly constant packet rate 1/T.sub.frame such that once delivered to the second node, buffer occupancy time for the subsequent packets is reduced in comparison with buffer occupancy time of the current packet monitored in said step (a).

A method for processing at least two isochronous connections established within a multinode packet switch network, said at least two isochronous connections including a first isochronous connection and a second isochronous connection which share a common switch port at a switch node of the multinode packet switch network, said at least two isochronous connections each providing a stream of packets to the common switch port, said streams of packets having the same nearly constant packet rate, 1/T.sub.frame, and independent packet phases, each of the at least two isochronous connection having a unique buffer allocation at the common switch port, said processing method comprising the steps of:

• (a) evaluating buffer occupancy time relative to said packet rate 1/T.sub.frame of at least one packet in the stream of packets provided through the first isochronous connection to the common switch port, and evaluating buffer occupancy time relative to said packet rate 1/T.sub.frame of at least one packet in the stream of packets provided through the second isochronous connection to the common switch port;
• and
• (b) combining buffer allocations for the first isochronous connection and the second isochronous connection such that the at least two isochronous connections share a buffer at the common switch node provided that there is no overlap in evaluated buffer occupancy times for the at least one packet of the first isochronous connection and the at least one packet of the second isochronous connection.

A multinode packet switch network having an established isochronous connection wherein a stream of packets propagates through the network at a nearly constant packet rate, 1/T.sub.frame, and packet phase, said packet switch network comprising:

• a first switch node and a second switch node through which the isochronous connection is established and the stream of packets propagates, said first switch node delivering the stream of packets to the second switch node at said nearly constant packet rate, 1/T.sub.frame, said second switch node including a buffer for temporarily retaining a current packet of the stream of packets;
• means for monitoring buffer occupancy time at the second switch node of the current packet of the stream of packets delivered from the first switch node to the second switch node;
• means for generating at the second switch node a feedback message representative of the monitored buffer occupancy time;
• means for sending the feedback message from the second switch node to the first switch node;
• and
• means for adjusting at the first switch node the packet phase of subsequent packets of the stream of packets relative to the nearly constant packet rate 1/T.sub.frame without affecting the nearly constant packet rate 1/T.sub.frame such that once delivered to the second switch node, buffer occupancy time for the subsequent packets is reduced in comparison with the monitored buffer occupancy time.

A multinode packet switch network having at least two isochronous connections established through a common switch port, each of said at least two isochronous connections having a stream of packets propagating therethrough, said streams of packets each having a fixed packet phase and a same nearly constant packet rate, 1/T.sub.frame into the common switch port, said at least two isochronous connections comprising a first isochronous connection and a second isochronous connection, said multinode packet switch network comprising:

• means for monitoring buffer occupancy time of a current packet in the stream of packets provided to the common switch port by the first isochronous connection;
• means for returning a feedback message along the first isochronous connection to a previous switch node of the multinode packet switch network, said feedback message being representative of the monitored buffer occupancy time;
• and
• means for adjusting at the previous switch node the packet phase of subsequent packets relative to the nearly constant packet rate 1/T.sub.frame of the stream of packets propagating through the first isochronous connection without affecting the nearly constant packet rate 1/T.sub.frame and such that once delivered to the common switch port buffer occupancy time for the subsequent packets is reduced in comparison with the monitored buffer occupancy time of the current packet.

A multinode packet switch network having at least two isochronous connections which share a common switch port at a switch node of the multinode packet switch network, said at least two isochronous connections each providing a stream of packets to the common switch port, said streams of packets having the same nearly constant packet rate, 1/T.sub.frame, and independent packet phases, each of the at least two isochronous connections having a unique buffer allocation at the common switch port, said at least two isochronous connections including a first isochronous connection and a second isochronous connection, said multinode packet switch network comprising:

• means for evaluating buffer occupancy time relative to the packet rate 1/T.sub.frame of at least one packet in the stream of packets provided through the first isochronous connection to the common switch port;
• means for evaluating buffer occupancy time relative to the packet rate 1/T.sub.frame of at least one packet in the stream of packets provided through the second isochronous connection to the common switch port;
• and
• means for combining buffer allocations for the first isochronous connection and the second isochronous connection such that the at least two isochronous connections share a buffer at the common switch port provided that there is no overlapping in evaluated buffer occupancy times for the at least one packet of the first isochronous connection and the at least one packet of the second isochronous connection.