Load sharing between L2TP tunnels

• US 7,139,276 B1
• Filed: 02/27/2001
• Issued: 11/21/2006
• Est. Priority Date: 02/27/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Sitaraman, Aravind, Sheth, Purnam Anil
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): Han, Clemence
• Application Number:
  US09/795,688
• Time in Patent Office: 2,093 Days
• Field of Search: 370/389, 370/469, 709/227, 709/238, 709/249
• US Class Current: 370/401
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering

Abstract

A method for load sharing between tunnels connecting communication networks includes receiving a communication from a subscriber using the first communication network, determining tunnel selection criteria for the communication, selecting one of the at least one tunnel based on the tunnel selection criteria and forwarding the communication on the selected tunnel. The tunnel selection criteria indicate the basis for selecting one of the tunnels. An apparatus for load sharing between tunnels connecting communication networks includes a receiving interface to receive a communication from a subscriber using the first communication network, a tunnel selection criteria determiner to determine tunnel selection criteria for the communication, a tunnel selector to select one of the tunnels based on the tunnel selection criteria and a session forwarder to forward the communication on the selected tunnel. In one aspect of the invention, load sharing is performed between Layer 2 Tunneling Protocol (L2TP) tunnels.

Claims

1. A method for load sharing between tunnels connecting communication networks, the method comprising:

initializing a tunnel database that includes tunnel selection criteria for at least one tunnel connecting a first communication network to at least one communication network;

after said initializing, receiving a communication from a subscriber using said first communication network;

determining said tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of said at least one tunnel;

ascertaining one or more available tunnels to a remote domain for said communication;

selecting one of said one or more available tunnels based on said tunnel selection criteria; and

forwarding said communication on the selected tunnel.

2. The method of claim 1 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

3. The method of claim 2 wherein said tunnels comprise L2TP tunnels.

4. A method for load sharing between tunnels connecting communication networks, the method comprising:

receiving a communication from a subscriber using a first communication network;

determining tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria stored in a previously initialized tunnel database;

selecting one of said at least one tunnel based on said tunnel selection criteria; and

forwarding said communication on the selected tunnel.

5. The method of claim 4 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

6. The method of claim 5 wherein said tunnels comprise L2TP tunnels.

7. The method of claim 6 wherein said selecting further comprises:

examining Type of Service (ToS) bits associated with said PPP session; and

selecting a tunnel based on said ToS bits.

8. The method of claim 6 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session; and

selecting a tunnel based on said VPI/VCI pair.

9. The method of claim 6 wherein said selecting further comprises randomly selecting a tunnel connected to said remote domain.

10. The method of claim 6 wherein said selecting further comprises:

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel to said remote domain having the most available bandwidth.

11. The method of claim 6 wherein said selecting further comprises:

determining a time at which said PPP session is received; and

selecting a tunnel based on said time.

12. The method of claim 6 wherein said selecting further comprises:

determining the time at which said PPP session is received;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel having the most available bandwidth at said time.

13. The method of claim 6 wherein said selecting further comprises:

examining Type of Service (ToS) bits associated with said PPP session;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said ToS bits and said available bandwidth.

14. The method of claim 6 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

determining a class of service based on said VPI/VCI pair;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said class of service and said available bandwidth.

15. The method of claim 6 wherein said selecting further comprises selecting a tunnel to said remote domain having the smallest number of tunneled sessions such that tunneled sessions are distributed evenly among tunnels to said remote domain.

16. A program storage device readable by a machine, embodying a program of instructions executable by the machine to perform a method to load share between tunnels connecting communication networks, the method comprising:

initializing a tunnel database that includes tunnel selection criteria for at least one tunnel connecting a first communication network to at least one communication network;

after said initializing, receiving a communication from a subscriber using said first communication network;

determining said tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of said at least one tunnel;

ascertaining one or more available tunnels to a remote domain for said communication;

selecting one of said one or more available tunnels based on said tunnel selection criteria; and

forwarding said communication on the selected tunnel.

17. The program storage device of claim 16 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

18. The program storage device of claim 17 wherein said tunnels comprise L2TP tunnels.

19. A program storage device readable by a machine, embodying a program of instructions executable by the machine to perform a method to load share between tunnels connecting communication networks, the method comprising:

receiving a communication from a subscriber using a first communication network;

determining tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria stored in a previously initialized tunnel database;

selecting one of said at least one tunnel based on said tunnel selection criteria; and

forwarding said communication on the selected tunnel.

20. The program storage device of claim 19 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

21. The program storage device of claim 20 wherein said tunnels comprise L2TP tunnels.

22. The program storage device of claim 21 wherein said selecting further comprises:

examining Type of Service (ToS) bits associated with said PPP session; and

selecting a tunnel based on said ToS bits.

23. The program storage device of claim 21 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session; and

selecting a tunnel based on said VPI/VCI pair.

24. The program storage device of claim 21 wherein said selecting further comprises randomly selecting a tunnel connected to said remote domain.

25. The program storage device of claim 21 wherein said selecting further comprises:

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel to said remote domain having the most available bandwidth.

26. The program storage device of claim 21 wherein said selecting further comprises:

determining a time at which said PPP session is received; and

selecting a tunnel based on said time.

27. The program storage device of claim 21 wherein said selecting further comprises:

determining the time at which said PPP session is received;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel having the most available bandwidth at said time.

28. The program storage device of claim 21 wherein said selecting further comprises:

examining Type of Service (ToS) bits associated with said PPP session;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said ToS bits and said available bandwidth.

29. The program storage device of claim 21 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

determining a class of service based on said VPI/VCI pair;

determining the available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said class of service and said available bandwidth.

30. The program storage device of claim 21 wherein said selecting further comprises selecting a tunnel to said remote domain having the smallest number of tunneled sessions such that tunneled sessions are distributed evenly among tunnels to said remote domain.

31. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

means for initializing a tunnel database that includes tunnel selection criteria for at least one tunnel connecting a first communication network to at least one communication network;

means for after said initializing, receiving a communication from a subscriber using said first communication network;

means for determining said tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of said at least one tunnel;

means for ascertaining one or more available tunnels to a remote domain for said communication;

means for selecting one of said one or more available tunnels based on said tunnel selection criteria; and

means for forwarding said communication on the selected tunnel.

32. The apparatus of claim 31 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

33. The apparatus of claim 32 wherein said tunnels comprise L2TP tunnels.

34. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

means for receiving a communication from a subscriber using a first communication network;

means for determining tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria stored in a previously initialized tunnel database;

means for selecting one of said at least one tunnel based on said tunnel selection criteria; and

means for forwarding said communication on the selected tunnel.

35. The apparatus of claim 34 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

36. The apparatus of claim 35 wherein said tunnels comprise L2TP tunnels.

37. The apparatus of claim 36 wherein said means for selecting further comprises:

means for examining Type of Service (ToS) bits associated with said PPP session; and

means for selecting a tunnel based on said ToS bits.

38. The apparatus of claim 36 wherein said means for selecting further comprises:

means for examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session; and

means for selecting a tunnel based on said VPI/VCI pair.

39. The apparatus of claim 36 wherein said means for selecting further comprises means for randomly selecting a tunnel connected to said remote domain.

40. The apparatus of claim 36 wherein said means for selecting further comprises:

means for determining the available bandwidth for at least one tunnel to said remote domain; and

means for selecting a tunnel to said remote domain having the most available bandwidth.

41. The apparatus of claim 36 wherein said means for selecting further comprises:

means for determining a time at which said PPP session is received; and

means for selecting a tunnel based on said time.

42. The apparatus of claim 36 wherein said means for selecting further comprises:

means for determining the time at which said PPP session is received;

means for determining the available bandwidth for at least one tunnel to said remote domain; and

means for selecting a tunnel having the most available bandwidth at said time.

43. The apparatus of claim 36 wherein said means for selecting further comprises:

means for examining Type of Service (ToS) bits associated with said PPP session;

means for determining the available bandwidth for at least one tunnel to said remote domain, and

means for selecting a tunnel based on said ToS bits and said available bandwidth.

44. The apparatus of claim 36 wherein said means for selecting further comprises:

means for examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

means for determining a class of service based on said VPI/VCI pair;

means for determining the available bandwidth for at least one tunnel to said remote domain; and

means for selecting a tunnel based on said class of service and said available bandwidth.

45. The apparatus of claim 36 wherein said means for selecting further comprises means for selecting a tunnel to said remote domain having the smallest number of tunneled sessions such that tunneled sessions are distributed evenly among tunnels to said remote domain.

46. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

a tunnel database initializer to initialize a tunnel database that includes tunnel selection criteria for at least one tunnel connecting a first communication network to at least one communication network;

a receiving interface to receive a communication from a subscriber using said first communication network after said tunnel database is initialized;

a tunnel selection criteria determiner to determine tunnel said selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of said at least one tunnel;

an available tunnel ascertainer to ascertain one or more available tunnels to a remote domain for said communication;

a tunnel selector to select one of said one or more available tunnels based on said tunnel selection criteria; and

a session forwarder to forward said communication on the selected tunnel.

47. The apparatus of claim 46 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

48. The apparatus of claim 47 wherein said tunnels comprise L2TP tunnels.

49. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

a receiving interface to receive a communication from a subscriber using a first communication network;

a tunnel selection criteria determiner to determine tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria stored in a previously initialized tunnel database;

a tunnel selector to select one of said at least one tunnel based on said tunnel selection criteria; and

a session forwarder to forward said communication on the selected tunnel.

50. The apparatus of claim 49 wherein said communication comprises a Point-to-Point Protocol (PPP) session.

51. The apparatus of claim 50 wherein said tunnels comprise L2TP tunnels.

52. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon Type of Service (ToS) bits associated with said PPP session.

53. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session.

54. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel to said remote domain based a pseudo-random process.

55. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon the available bandwidth for at least one tunnel to said remote domain.

56. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon the time at which a PPP session is received.

57. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon which tunnel has the most available bandwidth when said PPP session is received.

58. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon Type of Service (ToS) bits associated with said PPP session and upon the available bandwidth for at least one tunnel to said remote domain.

59. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel based upon a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session and upon the available bandwidth for at least one tunnel to said remote domain.

60. The apparatus of claim 51 wherein said tunnel selector is further configured to select a tunnel having the smallest number of tunneled sessions to said remote domain such that tunneled sessions are distributed evenly among tunnels to said remote domain.

61. A method for load sharing between tunnels connecting communication networks, the method comprising:

receiving a Point-to-Point Protocol (PPP) session from a subscriber using a first communication network;

determining tunnel selection criteria for said PPP session, said tunnel selection criteria indicating a basis for randomly selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain;

selecting one of said at least one L2TP tunnel based on said tunnel selection criteria; and

forwarding said PPP session on the selected tunnel.

62. A program storage device readable by a machine, embodying a program of instructions executable by the machine to perform a method to load share between tunnels connecting communication networks, the method comprising:

receiving a Point-to-Point Protocol (PPP) session from a subscriber using a first communication network;

determining tunnel selection criteria for said PPP session, said tunnel selection criteria indicating a basis for randomly selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain;

selecting one of said at least one L2TP tunnel based on said tunnel selection criteria; and

forwarding said PPP session on the selected tunnel.

63. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

means for receiving a Point-to-Point Protocol (PPP) session from a subscriber using a first communication network;

means for determining tunnel selection criteria for said PPP session, said tunnel selection criteria indicating a basis for randomly selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain;

means for selecting one of said at least one L2TP tunnel based on said tunnel selection criteria; and

means for forwarding said PPP session on the selected tunnel.

64. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

a receiving interface to receive a Point-to-Point Protocol (PPP) session from a subscriber using a first communication network;

a tunnel selection criteria determiner to determine tunnel selection criteria for said PPP session, said tunnel selection criteria indicating a basis for randomly selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain;

a tunnel selector to select one of said at least one L2TP tunnel based on said tunnel selection criteria; and

a session forwarder to forward said PPP session on the selected tunnel.

65. A method for load sharing between tunnels connecting communication networks, the method comprising:

receiving a communication from a subscriber using a first communication network, said communication comprising a Point-to-Point Protocol (PPP) session;

determining tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria based at least in part on one or more of;

one or more Type of Service (ToS) bits associated with said PPP session;

a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

the available bandwidth for at least one tunnel to said remote domain; and

a time at which said PPP session is received;

selecting one of said at least one L2TP tunnel based on said tunnel selection criteria; and

forwarding said communication on the selected tunnel.

66. The method of claim 65 wherein said selecting further comprises:

examining said one or more Type of Service (ToS) bits associated with said PPP session; and

selecting a tunnel based on said one or more ToS bits.

67. The method of claim 65 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session; and

selecting a tunnel based on said VPI/VCI pair.

68. The method of claim 65 wherein said selecting further comprises:

determining said available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel to said remote domain having said most available bandwidth.

69. The method of claim 65 wherein said selecting further comprises:

determining a time at which said PPP session is received; and

selecting a tunnel based on said time.

70. The method of claim 65 wherein said selecting further comprises:

determining said time at which said PPP session is received;

determining said available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel having said most available bandwidth at said time.

71. The method of claim 65 wherein said selecting further comprises:

examining one or more Type of Service (ToS) bits associated with said PPP session;

determining said available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said ToS bits and said available bandwidth.

72. The method of claim 65 wherein said selecting further comprises:

examining a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

determining a class of service based on said VPI/VCI pair;

determining said available bandwidth for at least one tunnel to said remote domain; and

selecting a tunnel based on said class of service and said available bandwidth.

73. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

means for receiving a communication from a subscriber using a first communication network, said communication comprising a Point-to-Point Protocol (PPP) session;

means for determining tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria based at least in part on one or more of;

one or more Type of Service (ToS) bits associated with said PPP session;

a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

the available bandwidth for at least one tunnel to said remote domain; and

a time at which said PPP session is received;

means for selecting one of said at least one L2TP tunnel based on said tunnel selection criteria; and

means for forwarding said communication on the selected tunnel.

74. An apparatus for load sharing between tunnels connecting communication networks, the apparatus comprising:

a receiving interface to receive a communication from a subscriber using a first communication network, said communication comprising a Point-to-Point Protocol (PPP) session;

a tunnel selection criteria determiner to determine tunnel selection criteria for said communication, said tunnel selection criteria indicating the basis for selecting one of at least one L2TP tunnel connecting said first communication network to at least one communication network comprising a remote domain, said tunnel selection criteria based at least in part on one or more of;

one or more Type of Service (ToS) bits associated with said PPP session;

a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

the available bandwidth for at least one tunnel to said remote domain; and

a time at which said PPP session is received;

a tunnel selector to select one of said at least one tunnel based on said tunnel selection criteria; and

a session forwarder to forward said communication on the selected tunnel.

75. The apparatus of claim 74 wherein said tunnel selector is further configured to:

examine said one or more Type of Service (ToS) bits associated with said PPP session; and

select a tunnel based on said ToS bits.

76. The apparatus of claim 74 wherein said tunnel selector is further configured to:

examine said Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session; and

select a tunnel based on said VPI/VCI pair.

77. The apparatus of claim 74 wherein said tunnel selector is further configured to:

determine said available bandwidth for at least one tunnel to said remote domain; and

select a tunnel to said remote domain having said most available bandwidth.

78. The apparatus of claim 74 wherein said tunnel selector is further configured to:

determine said time at which said PPP session is received; and

select a tunnel based on said time.

79. The apparatus of claim 74 wherein said tunnel selector is further configured to:

determine said time at which said PPP session is received;

determine said available bandwidth for at least one tunnel to said remote domain; and

select a tunnel having said most available bandwidth at said time.

80. The apparatus of claim 74 wherein said tunnel selector is further configured to:

examine Type of Service (ToS) bits associated with said PPP session;

determine said available bandwidth for at least one tunnel to said remote domain; and

select a tunnel based on said ToS bits and said available bandwidth.

81. The apparatus of claim 74 wherein said tunnel selector is further configured to:

examine a Virtual Path Identifier (VPI)/Virtual Channel Identifier (VCI) pair associated with said PPP session;

determine a class of service based on said VPI/VCI pair;

determine said available bandwidth for at least one tunnel to said remote domain; and

select a tunnel based on said class of service and said available bandwidth.