Method and apparatus for transporting time related information in a packet switched network

Patent metadata

Field	Value
Publication number	US-9628383-B2
Application number	US-201113326038-A
Country	US
Kind code	B2
Filing date	Dec 14, 2011
Priority date	Jun 1, 2011
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A time aware device for a packet switched network comprising at least one time tag processing unit adapted to process time tag data of a predetermined time tag data field (TTDF) provided within a header of a tagged data packet (TDP) transported in said packet switched network to provide time related information reflecting a delay undergone by said tagged data packet (TDP) during its transport in said packet switched network.

First claim

The invention claimed is:

1. A time aware device for a packet switched network, comprising:
at least one time tag processing unit, which processes time tag data of a predetermined time tag data field provided within a header of a tagged data packet transported in said packet switched network to provide time related information reflecting a delay undergone by said tagged data packet during its transport in said packet switched network,
wherein said header is a layer-two-Ethernet header of a tagged Ethernet packet transported in said packet switched network and said header comprising a destination address and a source address;
wherein said predetermined time tag data field provided within the header follows directly both said destination address and said source address, and

wherein said predetermined time tag data field is processed first by said at least one time tag processing unit;
a local time stamp generator for generating a local time stamp, and at least one ingress port,
wherein said local time stamp is stored by said at least one time tag processing unit in a device time stamp field comprised by said predetermined time tag data field of a time tagged data packet received at said ingress port,
wherein said predetermined time tag data field includes a traceability field, and
wherein said traceability field comprises a hop count field storing a hop counter incremented by the time aware device, said time aware device modifying the time stamp within said predetermined time tag data field.

2. The time aware device according to claim 1 ,
wherein said at least one time tag processing unit processes said time tag data of the predetermined time tag data field provided within the layer-two-Ethernet header of a tagged Ethernet packet transported in said packet switched network.

3. The time aware device according to claim 2 ,
the predetermined time tag data field further comprising:
an Ethertype field indicating the type of the Ethernet protocol of said tagged data packet;
a source time stamp field which stores a time stamp provided by a time aware master device having inserted the time tag data field into said layer-two-Ethernet header of said data packet;
a device time stamp field which stores a device time stamp of the time aware device indicating a local time of the time aware device when the data packet is received at an ingress port of said time aware device; and
a correction field which stores an accumulated delay value indicating the delay undergone by said tagged data packet during its transport in said packet switched network.

4. The time aware device according to claim 3 ,
the predetermined time tag data field further comprising:
a time tag identifier field, and
a time tag type field.

5. A time aware device for a packet switched network comprising:
at least one time tag processing unit adapted to process time tag data of a predetermined time tag data field provided within a header of a tagged data packet transported in said packet switched network to provide time related information reflecting a delay undergone by said tagged data packet during its transport in said packet switched network,
wherein said header comprises a destination address and a source address, and
wherein said predetermined time tag data field provided within the header follows directly both said destination address and said source address;
a local time stamp generator for generating a local time stamp, and
at least one ingress port,
wherein said local time stamp is stored by said at least one time tag processing unit in a device stamp field comprised by said predetermined time tag data field of a time tagged data packet received at said ingress port;
wherein said time tag processing unit detects a residence time of said data packet caused by an internal passage and/or processing of the data packet in the time aware device or network by comparing a local time stamp generated by the local time stamp generator of said time aware device with a time stamp read from the device time stamp field of the tagged data packet at an egress port of said time aware device or network.

6. The time aware device according to claim 5 ,
wherein said time tag processing unit adds the detected residence time to the delay value stored in the correction field of the time tag data field of the respective tagged data packet.

7. The time aware device according to claim 3 ,
wherein said time aware device is a time aware master device which receives a data packet from a higher layer entity and forwards a tagged data packet to a time aware intermediate device or a time aware slave device wherein said time aware master device comprises a master time tag processing unit which inserts said time tag data field into the header of the received data packet and puts a time stamp derived from a master clock into the source time stamp field of the inserted time tag data field to provide the tagged data packet.

8. A packet switched network comprising at least one time aware master device according to claim 7 ,
at least one time aware intermediate device wherein said time aware device is a time aware intermediate device which forwards a tagged data packet received from a time aware master device or from a previous intermediate time aware device to a following intermediate time aware device or a time aware slave device; and
at least one time aware slave device which receives a tagged data packet from a time aware intermediate device or from a time aware master device,
wherein said time aware slave device comprises a slave time tag processing unit which provides an ingress port time stamp generated by a local time stamp generator upon reception of the data packet at an ingress port of said time aware slave device.

9. The packet switched network according to claim 8 ,
wherein said packet switched network is a mobile phone network having base station controllers comprising a time aware master device and base stations comprising a time aware slave device.

10. The time aware device according to claim 3 ,
wherein said time aware device is a time aware intermediate device which forwards a tagged data packet received from a time aware master device or from a previous intermediate time aware device to a following intermediate time aware device or a time aware slave device.

11. A time aware device for a packet switched network comprising:
at least one time tag processing unit adapted to process time tag data of a predetermined time tag data field provided within a header of a tagged data packet transported in said packet switched network to provide time related information reflecting a delay undergone by said tagged data packet during its transport in said packet switched network,
wherein said header comprises a destination address and a source address, and wherein said predetermined time tag data field provided within the header follows directly both said destination address and said source address;
a local time stamp generator for generating a local time stamp, and
at least one ingress port,
wherein said local time stamp is stored by said at least one time tag processing unit in a device time stamp field comprised by said predetermined time tag data field of a time tagged data packet received at said ingress port;
wherein said time aware device is a time aware intermediate device which forwards a tagged data packet received from a time aware master device or from a previous intermediate time aware device to a following intermediate time aware device or a time aware slave device;
wherein the time aware intermediate device comprises an ingress unit having

Assignees

• Magee Anthony
• Adva Optical Networking Se

Inventors

• Magee Anthony

Classifications

• H04L45/70 Primary

  Routing based on monitoring results · CPC title

• H04J3/0697

  Synchronisation in a packet node · CPC title

• H04J3/0661

  using timestamps · CPC title

• H04J3/0673

  using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet · CPC title

• H04L12/413

  with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD] · CPC title