Aggregating end-to-end QoS signaled packet flows through label switched paths

• US 7,477,657 B1
• Filed: 05/08/2002
• Issued: 01/13/2009
• Est. Priority Date: 05/08/2002
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Murphy, James, Pan, Ping
• Primary Examiner(s): Sam; Phirin
• Application Number:
  US10/142,730
• Time in Patent Office: 2,442 Days
• Field of Search: None
• US Class Current: 370/468
• CPC Class Codes: H04L 41/5022 by giving priorities, e.g. assigning classes of service
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Techniques are described for supporting end-to-end resource reservation protocols, such as the Resource Reservation Setup Protocol (RSVP), using Multi-protocol Label Switching (MPLS). A routing device, such as an edge router coupling a local network to another network, aggregates packet flow reservation requests, and maps the resource requests to Labeled Switch Paths (LSPs) capable of supporting the requested resources. Requests having common forwarding equivalence classes may be aggregated to flow through a single LSP having resources, such as bandwidth, capable of supporting the requests. Routers and other devices within the network need not monitor and support state information associated with the individual end-to-end packet flows. A method, for example, includes mapping requests for end-to-end packet flows through a network to LSPs within the network, and forwarding packets associated with the end-to-end packet flows along the LSPs based on the mapping.

Claims

1. A method comprising:

receiving, in accordance with a resource reservation protocol and with an edge router of an intermediate network located between a source device and a destination, a request to reserve resources for a packet flow along a path through the intermediate network, wherein the request specifies a Quality of Service (QoS) class;

selecting, at the edge router, a Label Switched Path (LSP) within the intermediate network based on the QoS class specified within the request, wherein one or more of the devices along the LSP do not monitor resource allocation or maintain state information for the resource reservation protocol;

assigning a label to the request to encapsulate the request within a Multiprotocol Label Switching (MPLS) packet;

forwarding the MPLS packet along the LSP in accordance with the label;

receiving packets associated with the requested packet flow;

aggregating the packets with packets associated with other requested packet flows associated with the same QoS class;

assigning labels to the packets to encapsulate the packets within MPLS packets associated with the LSP; and

forwarding the MPLS packets in accordance with the labels.

2. The method of claim 1, wherein selecting comprises dynamically forming the LSP through the intermediate network in response to receiving the request.

3. The method of claim 1, wherein selecting comprises selecting the LSP from a set of LSPs.

4. The method of claim 1, wherein the QoS class specifies a bandwidth and a burst size, and wherein selecting the LSP comprises selecting the LSP from a set of LSPs to accommodate the requested bandwidth and burst size.

6. The method of claim 1, further comprising:

receiving packets associated with the packet flow;

assigning to the packets labels associated with the LSP to encapsulate the packets within MPLS packets; and

forwarding the packets in accordance with the labels.

7. The method of claim 1, wherein the request conforms to the Resource Reservation Setup Protocol (RSVP).

8. The method of claim 7, wherein the request specifies the destination for the packet flow within an RSVP-enabled network, and selecting a Label Switched Path (LSP) comprises selecting the LSP to have a termination point of an edge router coupled to the RSVP-enabled network.

9. The method of claim 1, wherein the edge router comprises a first edge router, and wherein the LSP is formed through the network to between the first edge router to a second edge router.

10. The method of claim 9, wherein receiving a request comprises receiving a request to establish an end-to-end packet flow from a host coupled to the first edge router to a host coupled to the second edge router.

11. The method of claim 1, wherein forwarding the MPLS packet comprises forwarding the packet in accordance with routing information for the intermediate network.

12. The method of claim 1, further comprising:

receiving packets associated with the requested packet flow;

forwarding the packets along the LSP and encapsulated within MPLS packets;

receiving status information for the LSP; and

forwarding the packets along a different LSP and encapsulated within MPLS packets in response to the status information.

5. A method comprising:

receiving, in accordance with a resource reservation protocol and with an edge router of an intermediate network located between a source device and a destination, a request to reserve resources for a packet flow along a path through the intermediate network, wherein the request specifies a Quality of Service (QoS) class;

determining an allowable QoS level of service for the source device;

rejecting the request when the requested QoS class exceeds the allowable level of service for the source device;

when the requested QoS class does not exceed the allowable level of service for the source device, selecting at the edge router a Label Switched Path (LSP) within the intermediate network based on the QoS class specified within the request, wherein one or more of the devices along the LSP do not monitor resource allocation or maintain state information for the resource reservation protocol;

assigning a label to the request to encapsulate the request within a Multiprotocol Label Switching (MPLS) packet;

forwarding the MPLS packet along the LSP in accordance with the label;

receiving packets associated with the requested packet flow;

aggregating the packets with packets associated with other requested packet flows associated with the same QoS class;

assigning labels to the packets to encapsulate the packets within MPLS packets associated with the LSP; and

forwarding the MPLS packets in accordance with the labels.

13. A method comprising:

at an edge router of an intermediate network between a source and a destination, mapping requests to reserve resources for end-to-end packet flows through the intermediate network to Label Switched Paths (LSPs) within the intermediate network by identifying groups of the packet flows having common forwarding equivalence classes and mapping the groups to respective LSPs, wherein devices within the intermediate network along the LSPs do not monitor resource allocation or maintain state information associated with the resource reservation protocol;

receiving, with the edge router, packets associated with the packet flows;

aggregating the packets for packet flows based on the common forwarding equivalence classes of the packet flows;

assigning to the packets Multiprotocol Label Switching (MPLS) labels based on the mapping to encapsulate the packets within MPLS packets; and

forwarding the MPLS packets along the LSPs based on the mapping.

14. The method of claim 13,

wherein the requests conform to a resource reservation protocol and specify quality of service (QoS) classes, and

wherein mapping the packet flows comprises mapping the packet flows to the LSPs based on:

(1) bandwidth requirements of the packet flows in accordance with the QoS classes, and (2) current bandwidth allocations of the LSPs.

15. The method of claim 13, further comprising:

receiving status information for the LSPs; and

updating the mapping based on the status information.

16. The method of claim 15, wherein receiving status information comprises receiving MPLS messages carrying the status information.

17. A method comprising:

receiving, at an edge router of an intermediate network between a source device and a destination, a plurality of requests that conform to the Resource Reservation Setup Protocol (RSVP), and that specify Quality of Service (QoS) requirements for packet flows through an intermediate network;

mapping the RSVP requests to a set of Label Switched Paths (LSPs) of the intermediate network based on the QoS requirements of the requests and current bandwidth allocations for the LSPs so that the LSP will carry the packet flows to meet the QoS requirements of the requests, wherein mapping further includes identifying groups of the packet flows having common forwarding equivalence classes; and

mapping the groups to respective LSPs, and wherein one or more devices within the intermediate network along the LSPs do not monitor resource allocation or maintain state information associated with the resource reservation protocol

receiving packets associated with the packet flows;

aggregating the packets for packet flows based on the QoS requirements;

assigning labels to the packets to encapsulate the packets within MPLS packets associated with the LSPs; and

forwarding the MPLS packets in accordance with the labels.

18. The method of claim 17, further comprising forwarding packets associated with the end-to-end packet flows along the LSPs based on the mapping.

19. A computer-readable medium encoded with data structures comprising:

reservation data representative of Resource Reservation Setup Protocol (RSVP) requests to reserve resources for packet flows through a network that does not monitor resource allocation associated with the packet flows in accordance with RSVP, wherein the reservation data includes a counter for a number of packets communicated through the packet flow;

path data representative of Label Switched Paths (LSPs) within the network that does not monitor resource allocation associated with the packet flows in accordance with RSVP; and

mapping data associating the RSVP requests with the LSPs to control forwarding of the packets through the LSPs of the network in accordance with the reservation data.

20. The computer-readable medium of claim 19, wherein the path data specifies an ingress device to the LSP, an egress device from the LSP, a bandwidth allocation for the LSP, and a current bandwidth usage for the LSP.

21. The computer-readable medium of claim 19, wherein the reservation data specifies a source device, a destination device, a bandwidth and burst size requested for the packet flow.

22. A computer-readable medium comprising instructions to cause a processor to:

receive a request to reserve resources for a packet flow along a path through a network, wherein the network does not monitor resource allocation associated with the packet flow, wherein the request specifies a Quality of Service (QoS) class;

select a Label Switched Path (LSP) within the network as a function of the QoS class;

assign a label to the request to encapsulate the request within a multiprotocol Label Switching (MPLS) packet;

forward the MPLS packet along the LSP in accordance with the label;

receive packets associated with the requested packet flow;

aggregate the packets with packets associated with other requested packet flows associated with the same QoS class;

assign labels to the packets to encapsulate the packets within MPLS packets associated with LSP; and

forward the MPLS packets in accordance with the labels.

23. The computer-readable medium of claim 22, further comprising instructions to initiate the formation of the LSP in response to receiving the request.

24. The computer-readable medium of claim 22, further comprising instructions to select the LSP from a set of LSPs.

26. The computer-readable medium of claim 22, wherein the request conforms to a network signaling protocol.

27. The computer-readable medium of claim 26, further comprising instructions to, wherein the request conforms to the Resource Reservation Setup Protocol (RSVP).

28. The computer-readable medium of claim 22, further comprising instructions to:

receive status information for the LSP; and

forward the packets along a different LSP in response to the status information.

25. A computer-readable medium comprising instructions to cause a processor to:

receive a Resource Reservation Setup Protocol (RSVP) request to reserve resources for a packet flow along a path through a network, wherein one or more label switch routers (LSRs) along the path does not monitor resource allocation associated with the packet flow as required by RSVP, wherein the request specifies a Quality of Service (QoS) class;

determine an allowable QoS class for the requested packet flow;

reject the RSVP request when the requested QoS class exceeds the allowable QoS class;

select a Label Switched Path (LSP) within the network as a function of the requested QoS class when the requested QoS class does not exceeds the allowable QoS class;

assign a label to the RSVP request to encapsulate the RSVP request within a multiprotocol Label Switching (MPLS) packet;

forward the MPLS packet along the LSP in accordance with the label;

receive packets associated with the requested packet flow;

aggregate the packets with packets associated with other requested packet flows associated with the same QoS class;

assign labels to the packets to encapsulate the packets within MPLS packets associated with LSP; and

forward the MPLS packets in accordance with the labels.

29. A routing device comprising:

a medium storing reservation data representative of requests to reserve resources for packet flows through a network, path data representative of Labeled Switch Paths (LSPs) within the network, wherein the requests conform to a resource reservation protocol unsupported by the network, and mapping data that associates the requests with the LSPs;

an interface to receive the requests; and

a control unit to forward packets associated with the packet flows along the LSPs based on the mapping data;

wherein the control unit updates the reservation data based on the request, selects respective LSPs to accommodate the requested packet flows, and updates the map data based on the selected LSPs, and

wherein the reservation data includes a counter for a number of packets communicated through the packet flow.

30. The routing device of claim 29 wherein, based on the mapping, the control unit assigns labels to the requests to encapsulate the request within Multiprotocol Label Switching (MPLS) packets, and forward the MPLS packets in accordance with the labels.

31. The routing device of claim 29 wherein, the path data specifies an ingress device to the LSP, an egress device from the LSP, a bandwidth allocation for the LSP, and a current bandwidth usage for the LSP.

32. The routing device of claim 29, wherein the reservation data specifies a source device, a destination device, a bandwidth and burst size requested for the packet flow.

33. The routing device of claim 29, wherein the control unit generates the mapping data to map the packet flows to the LSPs based on bandwidth requirements of the packet flows and current bandwidth allocations of the LSPs.

34. A routing device, comprising:

an access control module to generate a mapping between requests to reserve resources for end-to-end packet flows through a network and Labeled Switch Paths (LSPs) within the network, wherein the requests conform to a resource reservation protocol for reserving requests along paths through the network, and wherein the resource reservation protocol is unsupported by the network so that one or more devices within the network do not monitor resource allocation associated with the end-to-end packet flows;

an accounting module to generate accounting data describing Quality of Service requirements specified by the requests and consumption of bandwidth allocated to the LSPs; and

a control unit to forward packets associated with the end-to-end packet flows along the LSPs based on the mapping.

35. The routing device of claim 34, wherein the requests conform to the Resource Reservation Setup Protocol (RSVP), and that specify Quality of Service (QoS) requirements for packet flows through a network, and wherein the access control module maps the requests to the LSPs based on the QoS requirements of the requests and current bandwidth allocations for the LSPs.

36. The routing device of claim 34, wherein the access control module dynamically generates the mapping upon receiving the requests.

37. The routing device of claim 34, wherein the access control module receives configuration input describing a set of pre-established LSPs, and generates the mapping upon receiving the requests by selecting respective LSPs from the set.

38. The routing device of claim 34, further comprising a user interface to present the mapping to a user.

39. The routing device of claim 34, wherein the access control module receives status information for the LSPs, and updates the mapping based on the status information.

40. The routing device of claim 39, wherein the status information comprises MPLS messages carrying the status information.

41. A system comprising:

a first network having a first plurality of devices and a first router, wherein the first network executes a resource reservation protocol;

a second network having a second plurality of devices and a second router, wherein the second network executes the resource reservation protocol; and

an intermediate network coupling the first network to the second network, wherein the intermediate network does not monitor resource allocation associated with the end-to-end packet flows,

wherein the first and second routers receive resource reservation requests to reserve resources along end-to-end packet flows between devices of the first and second networks, and map the requests to a Labeled Switch Path (LSP) coupling the first and second networks through the intermediate network,

wherein the first and second routers updates reservation data based on the requests, select respective LSPs to accommodate the requested packet flows, and update the mapping based on the selected LSPs, and

wherein the first and second routers update the reservation data to maintain a counter for a number of packets communicated through each of the packet flows.

42. The system of claim 41, wherein the routers receive packets associated with the requested packet flows, and forward the packets along the LSP based on the mapping.

43. The system of claim 41, wherein the requests conform to the Resource Reservation Setup Protocol (RSVP).

44. The system of claim 41, wherein the routers assigns labels to the packets to encapsulate the packets within Multiprotocol Label Switching (MPLS) packets, and forward the MPLS packets in accordance with the labels.