Method and apparatus for providing quality of service using the internet protocol

• US 6,466,985 B1
• Filed: 04/09/1999
• Issued: 10/15/2002
• Est. Priority Date: 04/10/1998
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Goyal, Pawan, Hjalmtysson, Gisli
• Primary Examiner(s): VU, VIET DUY
• Application Number:
  US09/288,617
• Time in Patent Office: 1,285 Days
• Field of Search: 709/230, 709/232, 709/234, 709/235, 709/236, 709/237, 709/238, 709/245, 709/246, 709/250, 709/311, 370/230, 370/231, 370/235, 370/236
• US Class Current: 709/238
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A method and apparatus for communicating information in a network is described. A packet for the information is generated at a first network device. The first network device assigns a flow label to the packet. The flow label indicates that the packet is part of a particular sequence of packets. The first network device also assigns a direction to the packet by, for example, setting a bit in the flow label. The packet is then sent to a second network device through at least one intermediate network device. This process is continued for the entire sequence of packets. The intermediate network device actually routes the packets to the second network device. The intermediate network device receives the packets at an input port. A flow label is identified for each packet. The intermediate network device determines whether a flow table has an entry for the flow label. If there is no present entry for the flow label in the flow table, an entry for the flow label is created. If there is an entry for the flow label, an output port associated with the flow label is obtained. The intermediate network device then sends the packet to the output port. This continues at each intermediate network device until each packet reaches the second network device.

Claims

1. A method for communicating information in a network, comprising:

generating a packet for the information at a first network device;

assigning a flow label to said packet;

assigning a direction to said packet using said flow label, and wherein said flow label is reverse path forwarding enabled; and

sending said packet to a second network device through the network.

2. The method of claim 1, wherein said flow label is comprised of a plurality of bits, and wherein said step of assigning said direction comprises the step of setting one of said bits in said flow label.

3. A method for communicating information in a network, comprising:

receiving a first packet at a first input port of an intermediate network device;

identifying a flow label for said first packet;

determining whether a flow table has an entry for said flow label;

creating an entry for said flow label if no entry is present;

obtaining an output port associated with said flow label from said table; and

sending said first packet to said output port.

4. The method of claim 3, wherein said step of creating an entry comprises the steps of:

adding an entry for said flow label to said flow table;

determining whether said flow label has an associated routing attribute;

storing a pointer associated with said flow label in said flow table, said pointer pointing to an output port in a routing table for said intermediate network device, if said flow label does not have a routing attribute associated with it; and

storing said output port from said routing table in said flow table associated with said flow label, if said flow label does have a routing attribute associated with it.

5. The method of claim 3, further comprising the step of storing said first input port in said flow table associated with said flow label.

6. The method of claim 5, wherein said input and output ports for said intermediate network device are bidirectional, further comprising the steps of:

receiving a second packet at a second input port of said intermediate network device;

identifying a flow label for said second packet;

determining a direction for said second packet using said flow label; and

obtaining said first input port associated with said flow label from said flow table; and

sending said first packet to said first input port.

7. The method of claim 3, further comprising the steps of:

receiving a second packet at an input port of said intermediate network device;

identifying a flow label for said first packet;

determining whether said first and second packets should be aggregated; and

aggregating said first and second packets in accordance with said determination.

8. A method for requesting a connection-oriented packet flow between a first network device and a second network device in a packet network, comprising

allocating a flow label to the packet flow that has not been previously declared;

assigning the flow label to a header in a first packet of the packet flow;

adding any desired flow attributes to the header, and

sending the packet to the second network device through the network, where in the flow label that has not been previously declared is interpreted by the second network device as a request for a new packet flow and the second network device can utilizes the flow attributes in establishing state for the packet flow, and wherein the flow label includes an indication of direction for the flow.

9. The method of claim 8 wherein the second network device treats the flow label as a request to pin the route between the first network device and the second network device.

10. The method of claim 8 wherein the second network device may send another packet in a reverse path by using a second flow label including a different indication of direction for the flow.

11. The method of claim 10 wherein the flow attributes reflect quality of service attributes for the packet flow.

12. A network router comprising:

a processor;

a plurality of input/output (I/O) interfaces connected to the processor; and

one or more storage devices, connected to the processor, further comprising a routing table, a flow table, and a computer program which when executed by the processor performs a method of establishing a packet flow between the network router and a second network router comprising the steps of;

receiving a packet from the second network router with a flow label that has not been previously declare;

interpreting the flow label as a request for a new packet flow between the network router and the second network router; and

creating an entry for the flow label in the flow table, and wherein the flow label includes an indication of direction for the flow.

13. The network router of claim 12 wherein the request for a new packet flow is treated by the network router as an implicit request for route pinning between the network router and the second network router.

14. The network router of claim 12 wherein the network router may send another packet in a reverse path to the second network router by using a second flow label including a different indication of direction for the flow.

15. The network router of claim 14 wherein the packet includes quality of service attributes for the packet flow and wherein the network router can establish state based on the quality of service attributes.