AUTOMATIC ASSIGNMENT OF HARDWARE ADDRESSES WITHIN COMPUTER NETWORKS

• US 20120023207A1
• Filed: 07/20/2010
• Published: 01/26/2012
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Gandhewar, Sunil, Liddy, John
• Granted Patent: US 8,631,100 B2
• Time in Patent Office: Days
• US Class Current: 709/221
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]

Abstract

In general, techniques are described for automatic assignment of hardware addresses within computer networks. As one example, a network device comprising a physical network interface and a control unit may implement these techniques. The network interface receives a first message from a client device requesting a layer three (L3) network address. The first message also includes a layer two (L2) hardware address currently assigned to a network interface of the client device. The control unit selects a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message and generates a second message having a field that specifies the replacement L2 hardware address. The network interface outputs the second message to the client device so as to automatically assign the replacement L2 hardware address for use by the network interface of the client device.

Claims

1. A method comprising:

receiving, with a network device of a network, a first message from a client device of the network, wherein the first message requests that a layer three (L3) network address be reserved for use by the client device, and wherein the first message also includes a layer two (L2) hardware address currently assigned to a physical network interface of the client device;

selecting, with the network device, a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message;

generating, with the network device, a second message having a field that specifies the replacement L2 hardware address; and

outputting, with the network device, the second message to the client device in response to the first message so as to automatically assign the replacement L2 hardware address for use by the network interface of the client device.

2. The method of claim 1,

wherein receiving a first message comprises receiving a first message specifying an indication of whether the client device supports automatic reconfiguration of the L2 hardware address associated with the network interface of the client device, and

wherein selecting a replacement L2 hardware address includes selecting a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message based on the indication specified in the first message.

3. The method of claim 1,

wherein the client device comprises a first client device,

wherein the method further comprises determining whether the L2 hardware address included in the first message is currently in use by a second client device, and

wherein selecting a replacement L2 hardware address includes selecting, based on the determination, a replacement L2 hardware address for use by the network interface of the first client device as a replacement for the L2 hardware address included in the first message.

4. The method of claim 1,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message, and

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address.

5. The method of claim 1, further comprising:

after outputting the second message, receiving a third message from the client device requesting that a layer three (L3) network address be reserved for the client device, wherein the third message includes the replacement L2 hardware address to identify the same network interface of the client device as that identified previously by the L2 hardware address in the first message;

generating a fourth message that does not include the field specifying the replacement L2 hardware address, wherein the fourth message proposes a lease for a L3 network address; and

outputting the fourth message to the client device in response to the third message.

6. The method of claim 5,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message,

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address,

wherein the third message comprises another DHCP discover message that includes one or more of a client identifier option and an address field that specifies the replacement L2 hardware address, and

wherein the fourth message comprises another DHCP offer message that proposes the lease for the L3 network address.

7. The method of claim 1, further comprising:

storing data defining a layer two (L2) hardware address pool, wherein the L2 hardware address pool represents a set of L2 hardware addresses for use in the network by one or more client devices;

storing data defining a layer three (L3) network address pool, wherein the L3 network address pool represents a set of L3 network addresses for use in the network by the one or more client devices,

wherein selecting the replacement L2 hardware address for use by the network interface of the client device comprises selecting the replacement L2 hardware address from the L2 hardware address pool; and

selecting a L3 network address from the L3 hardware address pool for use by the client device in the network,

wherein generating a second message comprises generating the second message that additionally proposes a lease for the selected L3 network device in conjunction with having the field that specifies the replacement L2 hardware address.

8. The method of claim 1,

wherein the network device comprise either a router that implements a dynamic host configuration protocol (DHCP) server or a stand-alone DHCP server, and

wherein the client device comprises one or more of a personal computer, a laptop computer, a workstation, a cellular phone, a personal digital assistant (PDA), and a netbook.

9. The method of claim 1, further comprising dynamically programming, with the client device, the client device so that the network interface uses the replacement L2 hardware address in place of the L2 hardware address specified in the first message.

10. The method of claim 1, wherein the L2 hardware address specified in the first message comprises a null L2 hardware address,

wherein the method further comprises, in response to detecting that the L2 hardware address comprises the null L2 hardware address, determining that the network interface of the client device has not yet been programmed with a valid L2 hardware address, and

wherein selecting the replacement L2 hardware comprises selecting the replacement L2 hardware address for use by the network interface of the client device as a replacement for the null L2 hardware address included in the first message based on the determination that the network interface of the client device has not yet been programmed with a valid L2 hardware address.

11. The method of claim 1, wherein the first and second messages each conform to either a dynamic host configuration protocol (DHCP) for Internet protocol (IP) version four (DHCPv4) or a DHCP for IP version six (DHCPv6).

12. A network device, comprising:

a physical network interface that receives a first message from a client device of a network, wherein the first message requests that a layer three (L3) network address be reserved for use by the client device, and wherein the first message also includes a layer two (L2) hardware address currently assigned to the network interface of the client device;

a control unit that selects a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message and generates a second message having a field that specifies the replacement L2 hardware address, and

wherein the network interface outputs the second message to the client device in response to the first message so as to automatically assign the replacement L2 hardware address for use by the network interface of the client device.

13. The network device of claim 12,

wherein the first message specifies an indication of whether the client device supports automatic reconfiguration of the L2 hardware address associated with the network interface of the client device, and

wherein the control unit includes a server module comprising a L2 address allocation module that selects a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message based on the indication specified in the first message.

14. The network device of claim 12,

wherein the client device comprises a first client device,

wherein the control unit includes a server module comprising a L2 address allocation module that determines whether the L2 hardware address included in the first message is currently in use by a second client device, and

wherein the L2 address allocation module selects, based on the determination, a replacement L2 hardware address for use by the network interface of the first client device as a replacement for the L2 hardware address included in the first message.

15. The network device of claim 12,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message, and

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address.

16. The network device of claim 12,

wherein the network interface, after outputting the second message, receives a third message from the client device requesting that a layer three (L3) network address be reserved for the client device, wherein the third message includes the replacement L2 hardware address to identify the same network interface of the client device as that identified previously by the L2 hardware address in the first message,

wherein the control unit includes a server module that generates a fourth message that does not include the field specifying the replacement L2 hardware address, wherein the fourth message proposes a lease for a L3 network address, and

wherein the network interface outputs the fourth message to the client device in response to the third message.

17. The network device of claim 16,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message,

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address,

wherein the third message comprises another DHCP discover message that includes one or more of a client identifier option and an address field that specifies the replacement L2 hardware address, and

wherein the fourth message comprises another DHCP offer message that proposes the lease for the L3 network address.

18. The network device of claim 12,

wherein the control unit includes a server module that stores data defining a layer two (L2) hardware address pool, wherein the L2 hardware address pool represents a set of L2 hardware addresses for use in the network by one or more client devices and stores data defining a layer three (L3) network address pool, wherein the L3 network address pool represents a set of L3 network addresses for use in the network by the one or more client devices,

wherein the server module includes a L2 address allocation module that selects selecting the replacement L2 hardware address from the L2 hardware address pool, and

wherein the server module also includes a L3 address allocation module that selects a L3 network address from the L3 hardware address pool for use by the client device in the network, and

wherein the server module generates the second message that additionally proposes a lease for the selected L3 network device in conjunction with having the field that specifies the replacement L2 hardware address.

19. The network device of claim 12,

wherein the network device comprise either a router that implements a dynamic host configuration protocol (DHCP) server or a stand-alone DHCP server, and

wherein the client device comprises one or more of a personal computer, a laptop computer, a workstation, a cellular phone, a personal digital assistant (PDA), and a netbook.

20. The network device of claim 12, wherein the client device dynamically programs the client device so that the network interface uses the replacement L2 hardware address in place of the L2 hardware address specified in the first message.

21. The network device of claim 12, wherein the L2 hardware address specified in the first message comprises a null L2 hardware address,

wherein the control unit, in response to detecting that the L2 hardware address comprises the null L2 hardware address, determines that the network interface of the client device has not yet been programmed with a valid L2 hardware address and selects the replacement L2 hardware address for use by the network interface of the client device as a replacement for the null L2 hardware address included in the first message based on the determination that the network interface of the client device has not yet been programmed with a valid L2 hardware address.

22. The network device of claim 12, wherein the first and second messages each conform to either a dynamic host configuration protocol (DHCP) for Internet protocol (IP) version four (DHCPv4) or a DHCP for IP version six (DHCPv6).

23. A non-transitory computer-readable storage medium comprising instructions that cause a processor of a network device to:

receive a first message from a first client device of the network, wherein the first message requests that a layer three (L3) network address be reserved for use by the client device, and wherein the first message also includes a layer two (L2) hardware address associated with an network interface of the client device;

select a replacement L2 hardware address for use by the network interface of the client device as a replacement for the L2 hardware address included in the first message;

generate a second message having a field that specifies the replacement L2 hardware address; and

output the second message to the client device in response to the first message so as to automatically assign the replacement L2 hardware address for use by the network interface of the client device.

24. A method comprising:

generating, with a client device located in a sub-network (subnet) of a network, a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network, wherein the first message also includes a layer two (L2) hardware address associated with an network interface of the client device;

outputting, with the client device, the first message to a network device responsible for allocating leases for L3 network addresses to client devices;

receiving, with the client device, a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message; and

automatically replacing, with the client device, the L2 hardware address associated with the network interface of the client device with the replacement L2 hardware address specified in the second message.

25. The method of claim 24,

wherein generating a first message comprises generating the first message to include an indication of whether the client device supports automatic reconfiguration of the L2 hardware address associated with the network interface of the client device, and

wherein receiving the second message having the field that specifies the replacement L2 hardware address comprises receiving the second message having the field that specifies the replacement L2 hardware address based on the indication.

26. The method of claim 25,

wherein the indication indicates that the client device does not support automatic reconfiguration of the L2 hardware address, and

wherein receiving the second message comprises receiving the second message that does not have the field that specifies the replacement L2 hardware address as a result of the indication indicating that the client device does not support automatic reconfiguration of the L2 hardware address.

27. The method of claim 24,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message, and

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address.

28. The method of claim 24, further comprising:

after receiving the second message, generating a third message requesting that a layer three (L3) network address be reserved for the client device, wherein the third message includes the replacement L2 hardware address to identify the same network interface of the client device as that identified previously by the L2 hardware address in the first message;

outputting the third message to the network device; and

receiving a fourth message in response to the third message, wherein the fourth message does not include the field specifying the replacement L2 hardware address, and wherein the fourth message proposes a lease for a L3 network address.

29. The method of claim 28,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message,

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address,

wherein the third message comprises another DHCP discover message that includes a client identifier option that specifies the replacement L2 hardware address, and

wherein the fourth message comprises another DHCP offer message that proposes the lease for the L3 network address.

30. The method of claim 24,

wherein the network device comprise either a router that implements a dynamic host configuration protocol (DHCP) server or a stand-alone DHCP server, and

wherein the client device comprises one or more of a wireless access point (WAP), a computer, a laptop, a netbook, a portable device, a wireless handset, a personal digital assistant (PDA), a workstation, an Internet-capable appliance, an Internet-capable television, a printer, a server, a hub, and a switch.

31. The method of claim 24, wherein the layer two (L2) hardware address included within the first message comprises a null L2 hardware address to indicate that a L2 hardware address has not yet been assigned to the network interface.

32. The method of claim 24, wherein the first and second messages each conform to either a dynamic host configuration protocol (DHCP) for Internet protocol (IP) version four (DHCPv4) or a DHCP for IP version six (DHCPv6).

33. A client device comprising:

a physical network interface; and

a control unit that generates a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network, wherein the control unit generates the first message to specify a layer two (L2) hardware address currently assigned to the physical network interface of the client device,

wherein the network interface outputs the first message to a network device responsible for allocating leases for L3 network addresses to client devices and receives a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message, and

wherein the control unit outputs one or more signals to the physical network interface to automatically replace the L2 hardware address currently assigned to the network interface with the replacement L2 hardware address specified in the second message.

34. The client device of claim 33,

wherein the control unit includes a client module that generates the first message to include an indication of whether the client device supports automatic reconfiguration of the L2 hardware address associated with the network interface of the client device, and

wherein the network interface receives the second message having the field that specifies the replacement L2 hardware address based on the indication.

35. The client device of claim 34,

wherein the indication indicates that the client device does not support automatic reconfiguration of the L2 hardware address, and

wherein the network interface receives the second message that does not have the field that specifies the replacement L2 hardware address as a result of the indication indicating that the client device does not support automatic reconfiguration of the L2 hardware address.

36. The client device of claim 33,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message, and

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address.

37. The client device of claim 33,

wherein the control unit includes a client module that, after receiving the second message, generates a third message requesting that a layer three (L3) network address be reserved for the client device, wherein the third message includes the replacement L2 hardware address to identify the same network interface of the client device as that identified previously by the L2 hardware address in the first message, and

wherein the network interface outputs the third message to the network device and receives a fourth message in response to the third message, wherein the fourth message does not include the field specifying the replacement L2 hardware address, and wherein the fourth message proposes a lease for a L3 network address.

38. The client device of claim 37,

wherein the first message comprises a dynamic host configuration protocol (DHCP) discover message,

wherein the second message comprises a DHCP offer message having a type-length-value (TLV) field that specifies the replacement L2 hardware address,

wherein the third message comprises another DHCP discover message that includes a client identifier option that specifies the replacement L2 hardware address, and

wherein the fourth message comprises another DHCP offer message that proposes the lease for the L3 network address.

39. The client device of claim 33,

wherein the network device comprise either a router that implements a dynamic host configuration protocol (DHCP) server or a stand-alone DHCP server, and

wherein the client device comprises one or more of a wireless access point (WAP), a computer, a laptop, a netbook, a portable device, a wireless handset, a personal digital assistant (PDA), a workstation, an Internet-capable appliance, an Internet-capable television, a printer, a server, a hub, and a switch.

40. The client device of claim 33, wherein the layer two (L2) hardware address included within the first message comprises a null L2 hardware address to indicate that a L2 hardware address has not yet been assigned to the network interface.

42. A non-transitory computer-readable storage medium comprising instructions that cause a processor of a client device to:

generate a first message requesting that a layer three (L3) network address be reserved for use by the client device in a network, wherein the first message also includes a layer two (L2) hardware address associated with an network interface of the client device;

output the first message to a network device responsible for allocating leases for L3 network addresses to client devices;

receive a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message; and

automatically replace the L2 hardware address associated with the network interface of the client device with the replacement L2 hardware address specified in the second message.

43. A network system comprising:

a client device located in a sub-network (subnet) of a network; and

a dynamic host configuration protocol (DHCP) server located in the network that is responsible for allocating leases for L3 network addresses to client devices,

wherein the client device includes;

a first network interface; and

a first control unit that generates a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network, wherein the first message also includes a layer two (L2) hardware address associated with the first network interface of the client device,

wherein the first network interface outputs the first message to the DHCP server,

wherein the DHCP server includes;

a second network interface that receives the first message from the client device; and

a second control unit that selects a replacement L2 hardware address for use by the first network interface of the client device as a replacement for the L2 hardware address included in the first message and generates a second message having a field that specifies the replacement L2 hardware address,

wherein the second network interface outputs the second message to the client device,

wherein the first network interface of the client device receives the second message, and

wherein the first control unit automatically replaces the L2 hardware address associated with the first network interface of the client device with the replacement L2 hardware address specified in the second message.

44. A method comprising:

generating, with a client device located in a sub-network (subnet) of a network, a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network, wherein the first message also includes a layer two (L2) hardware address associated with an network interface of the client device;

outputting, with the client device, the first message to a network device responsible for allocating leases for L3 network addresses to client devices;

receiving, with the client device, a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message; and

indicating, with the client device, to a user of the client device that the user needs to change the L2 hardware address to the replacement L2 hardware address.

41. The client device of claim 44, wherein the first and second messages each conform to either a dynamic host configuration protocol (DHCP) for Internet protocol (IP) version four (DHCPv4) or a DHCP for IP version six (DHCPv6).

45. A method comprising:

generating, with a client device located in a sub-network (subnet) of a network, a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network;

outputting, with the client device, the first message to a network device responsible for allocating leases for L3 network addresses to client devices;

receiving, with the client device, a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message; and

indicating, with the client device, to a user of the client device that the user needs to change the L2 hardware address to the replacement L2 hardware address.

46. A method comprising:

generating, with a client device located in a sub-network (subnet) of a network, a first message requesting that a layer three (L3) network address be reserved for use by the client device in the network;

outputting, with the client device, the first message to a network device responsible for allocating leases for L3 network addresses to client devices;

receiving, with the client device, a second message having a field that specifies a replacement L2 hardware address for use in the network as a replacement for the L2 hardware address included in the first message; and

automatically programming, with the client device, a network interface of the client device with the replacement L2 hardware address specified in the second message.