Apparatus and method for determining timing for transmissions

A communication system comprising a communication network element;

• the communication network element comprising:
• a transmitter for transmitting at least one timing data packet to at least one further network element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• a receiver for receiving at least two timing data packets from the at least one further network element over the second communication link, wherein at least one of the at least two timing data packets corresponds to the timing data packet that was transmitted via the first communication link;
• and
• signal processing logic operably coupled to the transmitter and receiver, wherein the signal processing logic is operable to calculate a transit delay of the at least one transmitted timing data packet over the first communication link based on the at least two timing data packets received via the second communication link, and wherein the signal processing logic is further operable to schedule at least one transmission across the first communication link to the at least one further network element in response to the calculated transit delay.

A method for determining a timing of multicast transmissions from a network element, the method comprising:

• transmitting at least one timing data packet to at least one further network element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• receiving at least two timing data packets from the at least one further network element over the second communication link, wherein at least one of the at least two timing data packets corresponds to the time data packet that was transmitted via the first communication link;
• calculating a transit delay of the at least one transmitted timing data packet over the first communication link based on the at least two timing data packets received via the second communication link;
• and
• scheduling at least one transmission across the first communication link to the at least one further network element in response thereto.

An integrated circuit for determining a timing of multicast transmissions from a network element, wherein the integrated circuit comprises:

• logic for transmitting at least one timing data packet to at least one further network element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• logic for receiving at least two timing data packets from the at least one further network element over the second communication link, wherein at least one of the at least two timing data packets corresponds to the timing data packet that was transmitted via the first communication link;
• logic for calculating a transit delay of the at least one transmitted timing data packet over the first communication link based on the at least two timing data packets received via the second communication link;
• and
• logic for scheduling at least one transmission across the first communication link to the at least one further network element in response to the calculated transit delay.

A communication network element comprising:

• a receiver for receiving at least one timing data packet from a network controller element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• a transmitter for transmitting at least two timing data packets to the network controller element over the second communication link, wherein at least one of the at least two timing data packets corresponds to the timing data packet that was received via the first communication link;
• such that a transit delay of the at least one received timing data packet over the first communication link is calculated based on the at least two timing data packets,
• wherein the communication network element is operable to receive at least one scheduled transmission across the first communication link from the network controller element based on a calculated transit delay of a transmission over the first communication link.

An integrated circuit for a communication network element comprising:

• logic for receiving at least one timing data packet from a network controller element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• logic for transmitting at least two timing data packets to the network controller element over the second communication link, wherein at least one of the two timing data packets corresponds to the timing data packet that was received via the first communication link;
• such that a transit delay of the at least one timing data packet over the first communication link is calculated based on the at least two timing data packets,
• wherein the integrated circuit is operable to receive at least one scheduled transmission across the first communication link from the network controller element based on the calculated transit delay of the transmission over the first communication link.

A method for a communication network element comprising:

• receiving at least one timing data packet from a network controller element over both a first communication link that is unidirectional and a second communication link that is bidirectional;
• transmitting at least two timing data packets to the network controller element over the second communication link, wherein at least one of the two timing data packets corresponds to the timing data packet that was received via the first communication link;
• such that a transit delay of the at least one timing data packet over the first communication link is calculated based on the at least two timing data packets, and
• receiving at least one scheduled transmission across the first communication link from the network controller element based on the calculated transit delay of the transmission over the first communication link.