Mobile network device multi-link optimizations

• US 20070211723A1
• Filed: 03/10/2006
• Published: 09/13/2007
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Patel, Alpesh, Dommety, Gopal, Kulkarni, Milind
• Granted Patent: US 7,633,917 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

Methods and apparatus for performing optimizations for a mobile network device such as a Mobile Node or Mobile Router supporting multiple links to a Home Agent (or Correspondent Node in a Mobile IPv6 environment) are disclosed. During the registration process, link characteristics are transmitted in the registration request. From the link characteristics, it is possible to determine whether the mobile network device has roamed from a high to a low bandwidth link, or vice versa. A first set of optimizations may be performed when the mobile network device has roamed from a high to a low bandwidth link, while a second set of optimizations may be performed when the mobile network device has roamed from a low to a high bandwidth link. Some optimizations may be performed during the establishment of a TCP session, while others may be performed during or upon completion of the Mobile IP registration process.

Claims

1. In a Mobile Router supporting multiple tunnels between the Mobile Router and a Home Agent, a method of optimizing transmission bandwidth, comprising:

receiving a TCP SYN packet from a node, the TCP SYN packet being addressed to a Correspondent Node and specifying a MSS;

modifying the MSS of the TCP SYN packet; and

forwarding the modified TCP SYN packet to the Correspondent Node.

2. The method as recited in claim 1, further comprising:

ascertaining a MTU of each of a plurality of links available to the Mobile Router;

wherein modifying the MSS of the TCP SYN packet includes modifying the MSS of the TCP SYN packet to a MTU of one of the plurality of links.

3. The method as recited in claim 2, further comprising:

determining whether the MSS of the TCP SYN packet is greater than a MTU of one of the plurality of links;

wherein modifying includes modifying the MSS of the TCP SYN packet to a lowest MTU value associated with the plurality of links or to a lowest MTU value associated with those of the plurality of links that are up.

4. The method as recited in claim 3, wherein the one of the plurality of links has a MTU that is lower than the remaining ones of the plurality of links.

5. The method as recited in claim 1, further comprising:

receiving a TCP SYN ACK packet from the Correspondent Node, the TCP SYN ACK being addressed to the node and specifying a MSS;

modifying the MSS of the TCP SYN ACK packet and forwarding the modified TCP SYN ACK packet to the node;

receiving a TCP ACK from the node; and

forwarding the TCP ACK to the Correspondent Node.

6. In a Mobile Router supporting multiple tunnels between the Mobile Router and a Home Agent, a method of optimizing transmission bandwidth, comprising:

receiving a TCP SYN packet from a node, the TCP SYN packet being addressed to a Correspondent Node and specifying a MSS;

forwarding the TCP SYN packet to the Correspondent Node;

receiving a TCP SYN ACK packet from the Correspondent Node, the TCP SYN ACK being addressed to the node and specifying a MSS;

modifying the MSS of the TCP SYN ACK packet and forwarding the modified TCP SYN ACK packet to the node;

receiving a TCP ACK from the node; and

forwarding the TCP ACK to the Correspondent Node.

7. The method as recited in claim 6, further comprising:

ascertaining a MTU of each of a plurality of links available to the Mobile Router;

wherein modifying the MSS of the TCP SYN ACK packet includes modifying the MSS of the TCP SYN ACK packet to a MTU of one of the plurality of links.

8. The method as recited in claim 7, further comprising:

determining whether the MSS of the TCP SYN ACK packet is greater than a MTU of one of the plurality of links;

wherein modifying includes modifying the MSS of the TCP SYN ACK packet to a lowest MTU value associated with the plurality of links or to a lowest MTU value associated with those of the plurality of links that are up.

9. The method as recited in claim 8, wherein the one of the plurality of links has a MTU that is lower than the remaining ones of the plurality of links.

10. In a Mobile Router supporting multiple tunnels between the Mobile Router and a Home Agent, a method of optimizing transmission bandwidth, comprising:

receiving a TCP ACK packet from a Correspondent Node, the TCP ACK packet being addressed to a node that is coupled to the Mobile Router;

obtaining a sequence number from the TCP ACK packet;

generating one or more new TCP ACK packets, each of the one or more new TCP ACK packets including a number within a range of sequence numbers indicated by the sequence number; and

sending the one or more new TCP ACK packets to the node.

11. The method as recited in claim 10, wherein a source address of each of the new TCP ACK packets includes an IP address of the Correspondent Node.

12. The method as recited in claim 10, wherein generating and sending are performed when the Mobile Router moves from a low bandwidth to a high bandwidth link or registers with the Home Agent via a high bandwidth link.

13. The method as recited in claim 12, wherein the sequence number in each of the one or more new TCP ACK packets is different.

14. The method as recited in claim 10, wherein generating and sending are performed when the Mobile Router moves from a high bandwidth to a low bandwidth link or registers with the Home Agent via a low bandwidth link, wherein the sequence number in each of the one or more new TCP ACK packets is the same.

15. In a Home Agent supporting multiple tunnels between the Home Agent and a mobile network device, a method of optimizing transmission bandwidth, comprising:

receiving a TCP ACK packet from a node, the TCP ACK packet being addressed to a Correspondent Node;

obtaining a sequence number from the TCP ACK packet;

generating one or more new TCP ACK packets, each of the one or more new TCP ACK packets including a number within a range of sequence numbers indicated by the sequence number; and

sending the one or more new TCP ACK packets to the Correspondent Node.

16. The method as recited in claim 15, wherein the mobile network device is a Mobile Router.

17. The method as recited in claim 16, wherein the node is a node that is coupled to the Mobile Router.

18. The method as recited in claim 15, wherein the node is the mobile network device.

19. The method as recited in claim 15, wherein a source address of each of the new TCP ACK packets is an IP address of the node.

20. The method as recited in claim 15, wherein generating and sending are performed when the mobile network device moves from a low bandwidth to a high bandwidth link or registers with the Home Agent via a high bandwidth link.

21. The method as recited in claim 20, wherein the sequence number in each of the one or more new TCP ACK packets is different.

22. The method as recited in claim 15, wherein generating and sending are performed when the mobile network device moves from a high bandwidth to a low bandwidth link or registers with the Home Agent via a low bandwidth link, wherein the sequence number in each of the one or more new TCP ACK packets is the same.

23. In a Correspondent Node supporting multiple tunnels between the network device and a mobile network device, a method of optimizing transmission bandwidth, comprising:

receiving a TCP ACK packet from the mobile network device, the TCP ACK packet being addressed to the Correspondent Node;

obtaining a sequence number from the TCP ACK packet;

generating one or more new TCP ACK packets, each of the one or more new TCP ACK packets including a number within a range of sequence numbers indicated by the sequence number; and

sending the one or more new TCP ACK packets to the mobile network device.

24. The method as recited in claim 23, wherein the mobile network device is a Mobile Node supporting Mobile IPv6.

25. The method as recited in claim 23, wherein generating and sending are performed when the mobile network device moves from a high bandwidth to a low bandwidth link or registers with the network device via a low bandwidth link, wherein the sequence number in each of the one or more new TCP ACK packets is the same.

26. In a mobile network device, a method of registering with a Home Agent, comprising:

composing a registration request message including link characteristics;

sending the registration request to the Home Agent, the link characteristics being associated with a link via which the registration request message is sent to the Home Agent; and

receiving a registration reply from the Home Agent indicating success or failure of the registration with the Home Agent.

27. The method as recited in claim 26, wherein the mobile network device is a Mobile Node supporting Mobile IP.

28. The method as recited in claim 26, wherein the mobile network device is a Mobile Router.

30. The method as recited in claim 28, further comprising:

sending an ICMP source quench message to each node coupled to the Mobile Router, wherein a source IP address of the ICMP source quench message is an IP address of a Correspondent Node.

31. The method as recited in claim 30, wherein sending the ICMP source quench message is performed when it is determined that the Mobile Router has moved from a high bandwidth link to a low bandwidth link.

32. The method as recited in claim 28, further comprising:

determining whether the Mobile Router has moved from a high bandwidth link to a low bandwidth link.

33. The method as recited in claim 32, wherein the Mobile Router has moved from a high bandwidth link to a low bandwidth link when the link has a lower bandwidth than a link via which the Mobile Router has previously registered with the Home Agent.

34. The method as recited in claim 32, wherein determining whether the Mobile Router has moved from a high bandwidth link to a low bandwidth link comprises:

obtaining link characteristics associated with a previous session from a table; and

comparing the link characteristics associated with the previous session with link characteristics associated with a current session.

35. The method as recited in claim 32, further comprising:

sending an ICMP source quench message to each node coupled to the Mobile Router, wherein a source IP address of the ICMP source quench message is an IP address of a Correspondent Node;

wherein sending the ICMP source quench message is performed when the Mobile Router has determined that it has moved from a high bandwidth link to a low bandwidth link.

36. The method as recited in claim 32, further comprising:

sending a message to one or more nodes coupled to the Mobile Router indicating that a window size is zero;

wherein sending the message is performed when the Mobile Router has determined that it has moved from a high bandwidth link to a low bandwidth link

37. The method as recited in claim 32, further comprising:

filtering traffic according to priority when the Mobile Router has determined that it has moved from a high bandwidth link to a low bandwidth link.

29. The method 26, further comprising:

updating a table associating the link characteristics with the session.

38. In a mobile network node, a method of registering with a Correspondent Node, comprising:

composing a registration request message including link characteristics;

sending the registration request to the Correspondent Node, the link characteristics being associated with a link via which the registration request message is sent to the Correspondent Node; and

receiving a registration reply message from the Correspondent Node indicating success or failure of the registration with the Correspondent Node.

39. The method as recited in claim 38, wherein the registration request message is a Binding Update and the registration reply message is a Binding Acknowledgement.

40. The method as recited in claim 38, wherein the mobile network device is a Mobile Node supporting Mobile IPv6.

41. The method 38, further comprising:

updating a table associating the link characteristics with the session generated upon successful registration with the Correspondent Node.

42. In a Correspondent Node, a method of registering a mobile network device, comprising:

receiving a registration request message including link characteristics from the mobile network device, the link characteristics being associated with a link via which the registration request message is sent to the Correspondent Node; and

composing a registration reply message indicating success or failure of the registration with the Correspondent Node; and

sending the registration reply message to the mobile network device.

43. The method as recited in claim 42, wherein the registration request message is a Binding Update and the registration reply message is a Binding Acknowledgement.

44. The method as recited in claim 42, wherein the mobile network device is a Mobile Node supporting Mobile IPv6.

46. The method as recited in claim 42, further comprising:

sending an ICMP source quench message to the mobile network device, wherein a source IP address of the ICMP source quench message is an IP address of the Correspondent Node.

47. The method as recited in claim 46, wherein sending the ICMP source quench message is performed when the mobile network device has moved from a high bandwidth link to a low bandwidth link.

48. The method as recited in claim 42, further comprising:

determining whether the mobile network device has moved from a high bandwidth link to a low bandwidth link.

49. The method as recited in claim 48, wherein the mobile network device has moved from a high bandwidth link to a low bandwidth link when the link has a lower bandwidth than a link via which the mobile network device has previously registered with the Correspondent Node.

50. The method as recited in claim 48, wherein determining whether the mobile network device has moved from a high bandwidth link to a low bandwidth link comprises:

obtaining link characteristics associated with a previous session from a table; and

comparing the link characteristics associated with the previous session with link characteristics associated with a current session.

51. The method as recited in claim 48, further comprising:

sending an ICMP source quench message to the mobile network node, wherein a source IP address of the ICMP source quench message is an IP address of the Correspondent Node;

wherein sending the ICMP source quench message is performed when the Correspondent Node has determined that the mobile network device has moved from a high bandwidth link to a low bandwidth link.

52. The method as recited in claim 48, further comprising:

sending a message to the mobile network device indicating that a window size is zero;

wherein sending the message is performed when the Correspondent Node has determined that the mobile network device has moved from a high bandwidth link to a low bandwidth link

53. The method as recited in claim 48, further comprising:

filtering traffic according to priority when the mobile network device has moved from a high bandwidth link to a low bandwidth link.

45. The method 42, further comprising:

updating a table associating the link characteristics with the session.

54. In a network device, a method of registering a mobile network device with the network device, comprising:

receiving a registration request from the mobile network device, the registration request including link characteristics, the link characteristics being associated with a link via which the registration request message has been sent to the network device;

authenticating the mobile network device;

composing a registration reply indicating success or failure of the registration of the mobile network device with the network device, wherein a session is created when registration is successful;

sending the registration reply to the mobile network device; and

when registration is successful, updating a table associating the link characteristics with the session.

55. The method as recited in claim 54, wherein the mobile network device is a Mobile Node supporting Mobile IP.

56. The method as recited in claim 54, wherein the mobile network device is a Mobile Router.

57. The method as recited in claim 54, wherein the network device is a Home Agent.

58. The method as recited in claim 57, the method further comprising:

sending an ICMP source quench message to a Correspondent Node, wherein a source IP address of the ICMP source quench message is an IP address of the mobile network node.

59. The method as recited in claim 58, wherein sending the ICMP source quench message is performed when it is determined that the mobile network node has moved from a high bandwidth link to a low bandwidth link.

60. The method as recited in claim 54, further comprising:

determining whether the mobile network node has moved from a high bandwidth link to a low bandwidth link.

61. The method as recited in claim 60, wherein the mobile network node has moved from a high bandwidth link to a low bandwidth link when the link has a lower bandwidth than a link via which the mobile network node has previously registered with the network device.

62. The method as recited in claim 60, wherein determining whether the mobile network node has moved from a high bandwidth link to a low bandwidth link comprises:

obtaining link characteristics associated with a previous session from a table; and

comparing the link characteristics associated with the previous session with link characteristics associated with a current session.

63. The method as recited in claim 60, wherein the network device is a Home Agent, the method further comprising:

sending an ICMP source quench message to a Correspondent Node, wherein a source IP address of the ICMP source quench message is an IP address of the mobile network node;

wherein sending the ICMP source quench message is performed when it is determined that the mobile network node has moved from a high bandwidth link to a low bandwidth link.

64. The method as recited in claim 60, wherein the network device is a Home Agent, the method further comprising:

sending one or more messages to a Correspondent Node indicating that the window size is zero;

wherein sending the one or more messages is performed when it is determined that the mobile network node has moved from a high bandwidth link to a low bandwidth link.

65. The method as recited in claim 64, wherein a source IP address of each of the messages is an IP address of a node communicating with the Correspondent Node.

66. The method as recited in claim 54, wherein the network device is a Correspondent Node.

67. The method as recited in claim 66, further comprising:

sending an ICMP source quench message to the mobile network device, wherein a source IP address of the ICMP source quench message is an IP address of the network device;

wherein sending the ICMP source quench message is performed when it is determined that the mobile network device has moved from a high bandwidth link to a low bandwidth link.

68. The method as recited in claim 66, further comprising:

sending one or more messages to the mobile network device indicating that the window size is zero;

wherein sending the one or more messages is performed when it is determined that the mobile network device has moved from a high bandwidth link to a low bandwidth link.

69. The method as recited in claim 60, further comprising:

filtering traffic according to priority when it is determined that the mobile network device has moved from a high bandwidth link to a low bandwidth link.

70. The method as recited in claim 54, wherein the table is a mobility binding table.