Maintained message delivery during routing domain migration

• US 8,824,471 B2
• Filed: 06/01/2011
• Issued: 09/02/2014
• Est. Priority Date: 06/01/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Hui, Jonathan W., Vasseur, Jean-Philippe
• Primary Examiner(s): Moore, Jr., Michael J
• Application Number:
  US13/151,010
• Publication Number:
  US 20120307825A1
• Time in Patent Office: 1,189 Days
• Field of Search: None
• US Class Current: 370/390
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 40/32 for defining a routing cluster membership
• CPC Class Codes: H04W 40/36 due to handover

Abstract

In one embodiment, an ingress device of a first routing domain in a computer network buffers received packets, and in response to receiving a request from a particular node indicating that the particular node has migrated from the first routing domain to a second routing domain, determines how to reach the particular node in the second routing domain, and forwards the buffered received packets to the particular node in the second routing domain, accordingly. In another embodiment, a device in the first routing domain migrates from the first routing domain to a second routing domain, and determines its new IP address. The device may then send a request to the first ingress router to forward buffered packets for the device to the second routing domain at the new IP address, and may thus receive buffered packets forwarded from the first ingress router at the device in the second routing domain.

Claims

1. A method, comprising:

receiving an initial request from a particular node to buffer received packets;

in response to the received request, buffering the received packets at an ingress device of a first routing domain in a computer network;

receiving a request from a particular node indicating that the particular node has migrated from the first routing domain to a second routing domain; and

in response,

determining how to reach the particular node in the second routing domain; and

forwarding the buffered received packets to the particular node in the second routing domain.

2. The method as in claim 1, wherein buffering comprises:

buffering a select set of packets received by the ingress device.

3. The method as in claim 2, wherein the select set is selected from a group consisting of:

a particular type of packet, a particular class of service of packet, a particular priority of packet, and a particular destination of the packets.

4. The method as in claim 1, wherein forwarding comprises:

encapsulating one of the buffered received packets in a corresponding packet for forwarding having a destination address of the particular node in the second routing domain.

5. The method as in claim 1, wherein forwarding comprises:

encapsulating one of the buffered received packets in a corresponding multicast packet for forwarding having a unicast prefix, wherein the particular node in the second routing domain is configured to join a corresponding unicast-prefix-based multicast group to receive the forwarded multicast packet.

6. The method as in claim 1, wherein the request contains a timestamp indicating which packets have already been received by the particular node prior to migrating from the first routing domain, and wherein forwarding comprises:

forwarding only those packets not already received by the particular node prior to migrating from the first routing domain based on the timestamp.

7. The method as in claim 1, further comprising:

continuing to receive additional packets at the ingress device for a period of time after receiving the request from the particular node indicating that the particular node has migrated from the first routing domain to a second routing domain; and

forwarding the received additional packets to the particular node in the second routing domain.

8. The method as in claim 1, wherein the ingress device is a field area router (FAR), and wherein the routing domain is a Low power and Lossy Network (LLN) Personal Area Network (PAN).

9. An apparatus, comprising:

one or more network interfaces to communicate as an ingress device within a first routing domain in a computer network;

a processor coupled to the network interfaces and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

receive an initial request from a particular node to buffer received packets;

begin buffering the received packets in response to the received initial request;

receive a request from the particular node indicating that the particular node has migrated from the first routing domain to a second routing domain; and

in response,

determine how to reach the particular node in the second routing domain; and

forward the buffered received packets to the particular node in the second routing domain.

10. The apparatus as in claim 9, wherein the process when executed to buffer is operable to:

buffer a select set of packets received by the ingress device, wherein the select set is selected from a group consisting of;

a particular type of packet, a particular class of service of packet, a particular priority of packet, and a particular destination of the packets.

11. The apparatus as in claim 9, wherein the request contains a timestamp indicating which packets have already been received by the particular node prior to migrating from the first routing domain, and wherein the process when executed to forward is operable to:

forward only those packets not already received by the particular node prior to migrating from the first routing domain based on the timestamp.

12. The apparatus as in claim 9, wherein the apparatus is a field area router (FAR), and wherein the routing domain is a Low power and Lossy Network (LLN) Personal Area Network (PAN).

13. A method, comprising:

operating as a device in a first routing domain having a first ingress router, the device having a first Internet Protocol (IP) address;

migrating from the first routing domain to a second routing domain having a second ingress router;

determining a second IP address for the device based on migrating to the second routing domain;

sending a request to the first ingress router to forward buffered packets for the device to the second routing domain at the second IP address; and

receiving buffered packets forwarded from the first ingress router at the device in the second routing domain.

14. The method as in claim 13, further comprising:

sending an initial request from the device to the first ingress router prior to migrating to the second routing domain, the request to buffer the received packets in advance of migrating.

15. The method as in claim 13, further comprising:

joining a corresponding unicast-prefix-based multicast group to receive forwarded multicast packets from the first ingress router.

16. The method as in claim 13, further comprising:

determining a timestamp associated with packets received while the device is located within the first routing domain; and

inserting within the request a timestamp indicating which packets have already been received by the device prior to migrating from the first routing domain.

17. An apparatus, comprising:

one or more network interfaces to communicate within a first routing domain in a computer network, the first routing domain having a first ingress router, the apparatus having a first Internet Protocol (IP) address within the first routing domain;

a processor coupled to the network interfaces and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

migrate from the first routing domain to a second routing domain having a second ingress router;

determine a second IP address for the apparatus based on migrating to the second routing domain;

send a request to the first ingress router to forward buffered packets for the apparatus to the second routing domain at the second IP address; and

receive buffered packets forwarded from the first ingress router at the apparatus in the second routing domain.

18. The apparatus as in claim 17, wherein the process when executed is further operable to:

send an initial request to the first ingress router prior to migrating to the second routing domain, the request to buffer the received packets in advance of migrating.

19. The apparatus as in claim 17, wherein the process when executed is further operable to:

determine a timestamp associated with packets received while the apparatus is located within the first routing domain; and

insert within the request a timestamp indicating which packets have already been received by the apparatus prior to migrating from the first routing domain.