Client addressing and roaming in a wireless network

• US 9,210,034 B2
• Filed: 02/28/2008
• Issued: 12/08/2015
• Est. Priority Date: 03/01/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Gil, Thomer M., Biswas, Sanjit, Bicket, John
• Primary Examiner(s): GREENE, JOSEPH L
• Application Number:
  US12/039,557
• Publication Number:
  US 20080288614A1
• Time in Patent Office: 2,840 Days
• Field of Search: 709217-222
• US Class Current: 1/1
• CPC Class Codes: H04L 2101/622 Layer-2 addresses, e.g. medium access control [MAC] addresses
• CPC Class Codes: H04L 41/0246 Exchanging or transporting network management information using the Internet; Embedding network management web servers in network elements; Web-services-based protocols
• CPC Class Codes: H04L 41/026 using e-messaging for transporting management information, e.g. email, instant messaging or chat
• CPC Class Codes: H04L 41/04 Network management architectures or arrangements
• CPC Class Codes: H04L 41/0803 Configuration setting
• CPC Class Codes: H04L 41/22 comprising specially adapted graphical user interfaces [GUI]
• CPC Class Codes: H04L 41/34 Signalling channels for network management communication
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5092 by self-assignment, e.g. picking addresses at random and testing if they are already in use
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A managed network receives client device requests for network addresses for communications over the managed network and computes a network address for a client device based on a hardware address of the client device, such as the MAC address of the client device, and returns the network address to the client device along with a predetermined gateway address for communications over the managed network with external networks. The MAC address is hashed to the network address that is assigned such that the client address will always receive the same network address whenever it accesses the managed network.

Claims

1. A method of network addressing for a client device using a wireless network communication protocol, the method comprising:

receiving a first dynamic host configuration protocol (DHCP) request at a first of a plurality of network traffic devices from the client device for an Internet protocol (IP) address for the client device over a local area network (LAN) associated with the first network traffic device, each of the plurality of network traffic devices operating in an infrastructure mode as one of a gateway device and a wireless access point (AP), wherein the network traffic devices form a wireless mesh network, wherein each of the network traffic devices operating in the infrastructure mode as a gateway device performs network address translation (NAT) for client devices currently associated with, wherein each of the network traffic devices is configured to generate, responsive to DHCP requests from client devices, IP addresses based on applying a predetermined arithmetic function on hardware identifiers of the respective client devices without using a centralized DHCP server, such that the same IP addresses will be assigned to the same client devices when roaming amongst different ones of the network traffic devices, wherein operating in infrastructure mode comprises each of the client devices being coupled to one or more of the plurality of network traffic devices;

extracting, by the first network traffic device, a hardware identifier from the first DHCP request, the hardware identifier uniquely identifying the client device;

computing, at the first network traffic device, a first IP address for the client device based on applying the predetermined arithmetic function on the hardware identifier of the client device without using the centralized DHCP server; and

returning a first DHCP response to the client device over the LAN, the first DHCP response including the first IP address to be assigned to the client device and a predetermined gateway IP address for reaching a first gateway device associated with the first network traffic device, the first gateway device providing an interface between the first network traffic device and the Internet,

wherein every one of the plurality of network traffic devices provides the same predetermined gateway IP address to be used for reaching a gateway device associated with that network traffic device, wherein client devices roaming between the network traffic devices will be assigned their same respective IP addresses and will receive the same predetermined gateway IP address from every one of the plurality of network traffic devices.

2. The method as defined in claim 1, wherein the hardware identifier of the client device comprises a media access control (MAC) address of the client device, and computing a first IP address comprises performing a hash function on the MAC address of the client device.

3. The method as defined in claim 2, wherein performing a hash function on the MAC address of the client device comprises:

hashing, using the hash function, six bytes of the MAC address of the client device to form least significant three bytes of the first IP address; and

assigning the most significant byte of the first IP address with a predetermined subnet value, such that all client devices associated with the plurality of network traffic devices is associated with an identical subnet.

4. The method as defined in claim 3, further comprising replacing the least significant byte of the first IP address with a decimal value of 254, if the least significant byte of the first IP address equals to a decimal value of 255 as a result of the hash function.

5. The method as defined in claim 3, further comprising replacing the least significant byte of the first IP address with a decimal value of 1, if the least significant bye of the first IP address equals to a decimal value of 0 as a result of the hash function.

6. The method as defined in claim 1, further comprising:

receiving a second DHCP request at a second one of the plurality of the network traffic devices from the client device for an IP address, wherein the client device wirelessly roams from the first network traffic device to the second network traffic device;

extracting, by the second network traffic device, the hardware identifier of the client device from the second DHCP request;

computing a second IP network address for the client device at the second network traffic device based on the hardware identifier of the client device using the predetermined arithmetic function, such that the second IP address and the first IP address are identical; and

returning a second DHCP response to the client device, the second DHCP response including the second IP address for the client device and the predetermined gateway IP address to reach a second gateway device associated with the second network traffic device, wherein the second gateway device provides an interface between the second network traffic device and the Internet, wherein the first gateway device and the second gateway device are represented by the same predetermined gateway IP address.

7. The method as defined in claim 1, wherein client devices roaming between the network traffic devices will not lose their link level connections when roaming between different ones of the network traffic devices because the client devices will be assigned their same respective IP addresses and will receive the same predetermined gateway IP address and gateway MAC address for every one of the plurality of network traffic devices.

8. The method as defined in claim 6, wherein with the same IP address assigned to the client device, the first and second network traffic devices do not have to exchange address resolution protocol (ARP) information with each other for intra-network communications concerning the client device.

9. The method as defined in claim 1, wherein with the same IP address of the client device, the network traffic devices do not have to resolve new network addresses from repeated address resolution protocol (ARP) operations when the client device roams amongst the network traffic devices.

10. The method as defined in claim 1, wherein every one of the network traffic devices is associated with an identical service set identifier (SSID).

11. The method as defined in claim 2, wherein the hash function comprises a cyclic redundancy check 32 (CRC-32) function.

12. The method as defined in claim 1, wherein the plurality of the network traffic devices are managed by a host server over the Internet, forming a logical managed network, wherein the network traffic devices are owned by a network owner, wherein the host server provides a set of management tools via a Web portal to allow the network owner to configure the network traffic devices over the Internet using a Web browser.

25. The method of claim 6, wherein the first gateway device and the second gateway device are represented by an identical predetermined gateway media access control (MAC) address.

26. The method as defined in claim 25, wherein the first network traffic device is a first wireless access point behind the first gateway device, and wherein the second network traffic device is a second wireless access point behind the second gateway device.

27. The method of claim 25, wherein the first network traffic device is a first gateway access point having the first gateway device integrated therein, and wherein the second network traffic device is a second gateway access point having the second gateway device integrated therein.

13. A non-transitory computer readable medium having instructions stored therein, which when executed by a processor, cause the processor to perform operations comprising:

receiving a first dynamic host configuration protocol (DHCP) request at a first of a plurality of network traffic devices, operating in an infrastructure mode, from a client device for an Internet protocol (IP) address for the client device over a local area network (LAN) associated with the first network traffic device, each of the plurality of network traffic devices operating as one of a gateway device and a wireless access point (AP), wherein the network traffic devices form a wireless mesh network, wherein each of the network traffic devices operating as a gateway device performs network address translation (NAT) for client devices currently associated with, wherein each of the network traffic devices is configured to generate, responsive to DHCP requests from client devices, IP addresses based on applying a predetermined arithmetic function on hardware identifiers of the respective client devices without using a centralized DHCP server, such that the same IP addresses will be assigned to the same client devices when roaming amongst different ones of the network traffic devices, wherein operating in infrastructure mode comprises each of the client devices being coupled to one or more of the plurality of network traffic devices;

extracting, by the first network traffic device, a hardware identifier from the first DHCP request, the hardware identifier uniquely identifying the client device;

computing, at the first network traffic device, a first IP address for the client device based on applying the predetermined arithmetic function on a hardware identifier of the client device without using the centralized DHCP server; and

returning a first DHCP response to the client device over the LAN, the first DHCP response including the first IP address to be assigned to the client device and a predetermined gateway IP address for reaching a first gateway device associated with the first network traffic device, the first gateway device providing an interface between the first network traffic device and the Internet, wherein every one of the plurality of network traffic devices provides the same predetermined gateway IP address to be used for reaching a gateway device associated with that network traffic device, wherein client devices roaming between the network traffic devices will be assigned their same respective IP addresses and will receive the same predetermined gateway IP address from every one of the plurality of network traffic devices.

14. The non-transitory computer-readable medium as defined in claim 13, wherein the hardware identifier of the client device comprises a media access control (MAC) address of the client device, and computing a first IP address comprises performing a hash function on the MAC address of the client device.

15. The non-transitory computer-readable medium as defined in claim 14, wherein performing a hash function on the MAC address of the client device comprises:

hashing, using the hash function, six bytes of the MAC address of the client device to form least significant three bytes of the first IP address; and

assigning the most significant byte of the first IP address with a predetermined subnet value, such that all client devices associated with the network traffic devices is associated with an identical subnet.

16. The non-transitory computer-readable medium as defined in claim 15, wherein the method further comprises replacing the least significant byte of the first IP address with a decimal value of 254, if the least significant byte of the first IP address equals to a decimal value of 255 as a result of the hash function.

17. The non-transitory computer-readable medium as defined in claim 15, wherein the method further comprises replacing the least significant byte of the first IP address with a decimal value of 1, if the least significant bye of the first IP address equals to a decimal value of 0 as a result of the hash function.

18. The non-transitory computer-readable medium as defined in claim 13, wherein the method further comprises:

receiving a second DHCP request at a second one of the plurality of the network traffic devices from the client device for a network address for network communications issued by the second network traffic device, wherein the client device wirelessly roams from the first network traffic device to the second network traffic device;

extracting, by the second network traffic device, the hardware identifier of the client device from the second DHCP request;

computing a second IP network address for the client device at the second network traffic device based on the hardware identifier of the client device using the predetermined arithmetic function, such that the second IP address and the first IP address are identical; and

returning a second DHCP response to the client device, the second DHCP response including the second IP address for the client device and the predetermined gateway IP address to reach a second gateway device associated with the second network traffic device, wherein the second gateway device provides an interface between the second network traffic device and the Internet, wherein the first gateway device and the second gateway device are represented by the same predetermined gateway IP address.

19. The non-transitory computer-readable medium as defined in claim 14, wherein client devices roaming between the network traffic devices will not lose their link level connections when roaming between different ones of the network traffic devices because the client devices will be assigned their same respective IP addresses and will receive the same predetermined gateway IP address and gateway MAC address for every one of the plurality of network traffic devices.

20. The non-transitory computer-readable medium as defined in claim 18, wherein with the same IP address assigned to the client device, the first and second network traffic devices do not have to exchange address resolution protocol (ARP) information with each other for intra-network communications concerning the client device.

21. The non-transitory computer-readable medium as defined in claim 13, wherein the plurality of the network traffic devices are managed by a host server over the Internet, forming a logical managed network, wherein the network traffic devices are owned by a network owner, wherein the host server provides a set of management tools via a Web portal to allow the network owner to configure the network traffic devices over the Internet using a Web browser.

22. A network traffic device, comprising:

a wireless network interface to receive a first dynamic host configuration protocol (DHCP) request from a client device for an Internet protocol (IP) address for the client device over a local area network (LAN) associated with the network traffic device, the network traffic device being one of a plurality of network traffic devices, wherein each of the plurality of network traffic devices operates as one of a gateway device and a wireless access point (AP), forming a wireless mesh network, wherein each of the network traffic devices operating in an infrastructure mode as a gateway device performs network address translation (NAT) for client devices currently associated with, wherein each of the network traffic devices is configured to generate, responsive to DHCP requests from client devices, IP addresses based on applying a predetermined arithmetic function on hardware identifiers of the respective client devices without using a centralized DHCP server, such that the same IP addresses will be assigned to the same client devices when roaming amongst different ones of the network traffic devices, wherein operating in infrastructure mode comprises each of the client devices being coupled to one or more of the plurality of network traffic devices; and

a processor coupled to the network interface, where in the processor is configured to extract a hardware identifier from the first DHCP request, the hardware identifier uniquely identifying the client device, compute a first IP address for the client device based on applying the predetermined arithmetic function on a hardware identifier of the client device without using the centralized DHCP server, and

return via the wireless network interface a first DHCP response to the client device, the first DHCP response including the first IP address to be assigned to the client device and a predetermined gateway IP address for reaching a first gateway device associated with the network traffic device, the first gateway device providing an interface between the network traffic device and the Internet, wherein every one of the plurality of network traffic devices provides the same predetermined gateway IP address to be used for reaching a gateway device associated with that network traffic device, wherein client devices roaming between the network traffic devices will be assigned their same respective IP addresses and will receive the same predetermined gateway IP address from every one of the plurality of network traffic devices.

23. The network traffic device as defined in claim 22, wherein the hardware identifier of the client device comprises a media access control (MAC) address of the client device, and computing the first IP address comprises performing a hash function on the MAC address of the client device.

24. The network traffic device as defined in claim 23, wherein performing a hash function on the MAC address of the client device comprises:

hashing, using the hash function, six bytes of the MAC address of the client device to form least significant three bytes of the first IP address; and

assigning the most significant byte of the first IP address with a predetermined subnet value, such that all client devices associated with the network traffic devices is associated with an identical subnet.

28. A system for providing network access to a plurality of client devices over local area networks (LANs), the system comprising:

a plurality of network traffic devices, each operating in an infrastructure mode as one of a gateway device and a wireless access point, wherein operating in infrastructure mode comprises each of the plurality of client devices being coupled to one or more of the plurality of network traffic devices, and wherein the network traffic devices form a wireless mesh network to provide network access to the plurality of client devices over the LANs, wherein each of the network traffic devices operating in the infrastructure mode as a gateway device performs network address translation (NAT) for client devices currently associated with, wherein each of the network traffic devices is configured to generate, responsive to dynamic host configuration protocol (DHCP) requests from client devices, Internet protocol (IP) addresses based on applying a predetermined arithmetic function on media access control (MAC) addresses of the respective client devices without using a centralized DHCP server, such that the same IP addresses will be assigned to the same client devices when roaming amongst different ones of the network traffic devices, wherein the plurality of network traffic devices comprises;

a first wireless access point for providing network access for a plurality of first client devices over a first LAN,

a first gateway device to provide an interface between the first wireless access point and the Internet to allow the plurality of first client devices to reach the Internet via the first wireless access point, wherein the first gateway device is represented by a predetermined gateway IP address and a predetermined gateway MAC address,

a second wireless access point for providing network access for a plurality of second client devices over a second LAN, and

a second gateway device to provide an interface between the second wireless access point and the Internet to allow the plurality of second client devices to reach the Internet via the second wireless access point, wherein the second gateway device is represented by the same predetermined gateway IP address and the same predetermined gateway MAC address,

wherein the first wireless access point is configured to receive a first DHCP request from a third client device over the first LAN requesting for an IP address,

in response to the first DHCP request, extract a MAC address of the third client device from the first DHCP request,

compute a first IP address for the third client device by applying the predetermined arithmetic function on the MAC address of the third client device without using a centralized DHCP server, and

return a first DHCP response to the third client device over the first LAN, the first DHCP response including the first IP address and the predetermined gateway IP address to allow the third client device to reach the first gateway device via the first wireless access point,

wherein the second wireless access point is configured to

receive a second DHCP request from the third client device over the second LAN requesting for a new IP address, the third client device roaming from the first wireless access point to the second wireless access point,

in response to the second DHCP request, extract the MAC address of the third client device from the second DHCP request,

compute a second IP address for the third client device by applying the same predetermined arithmetic function on the MAC address of the third client device without using a centralized DHCP server, and

return a second DHCP response to the third client device over the second LAN, the second DHCP response including the second IP address and the predetermined gateway IP address to allow the third client device to reach the second gateway device via the second wireless access point, and

wherein the first IP address and the second IP address are identical; and

a host server communicatively coupled to the network traffic devices over the Internet, wherein the host server is to manage the network traffic devices, forming a logical managed network, wherein the network traffic devices are owned by a network owner, wherein the host server provides a set of management tools via a Web portal to allow the network owner to configure the network traffic devices over the Internet using a Web browser.