SYSTEM AND METHOD FOR HANDLING ADDRESS RESOLUTION PROTOCOL REQUESTS

• US 20070286209A1
• Filed: 06/12/2006
• Published: 12/13/2007
• Est. Priority Date: 06/12/2006
• Status: Abandoned Application

• Current Assignee: Blackberry Limited
• Original Assignee: Blackberry Limited
• Inventors: Wang, James, Dunk, Craig
• Application Number:
  US11/423,533
• Publication Number:
  US 20070286209A1
• Time in Patent Office: Days
• US Class Current: 370/395.540
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 61/5069 for group communication, multicast communication or broadcast communication
• CPC Class Codes: H04L 61/58 Caching of addresses or names
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

A system and method for handling address resolution protocol requests at an intermediary device in a local area network. The intermediary device has an address resolution protocol cache for mapping Internet protocol addresses to physical layer addresses for devices in the local area network. The intermediary device receives a multicast address resolution protocol request having an Internet protocol address for a device on the local area network. The address resolution protocol address contained in the multicast address resolution protocol request is extracted and the address resolution protocol cache is accessed to seek to obtain a physical layer address mapped to the extracted Internet protocol address. As a result, a directed address resolution protocol request is forwarded from the intermediary device to the local area network device corresponding to the physical layer address obtained from the intermediary device data memory.

Claims

1. A computing-device program product for handling address resolution protocol requests, the computing-device program product comprising code executable on an intermediary device in a local area network, the intermediary device comprising data memory for mapping Internet protocol addresses to physical layer addresses for devices in the local area network,

(a) the code being operable on the intermediary device to receive a multicast address resolution protocol request having an Internet protocol address for a device on the local area network,

(b) the code being further operable, on receipt of the multicast address resolution protocol request, to extract the Internet protocol address contained in the multicast address resolution protocol request,

(c) the code being further operable to access the data memory in the intermediary device to obtain a physical layer address mapped to the extracted Internet protocol address if the Internet protocol address is present in the data memory, and

(d) the code being further operable to forward a directed address resolution protocol request to the local area network device corresponding to the physical layer address obtained from the intermediary device data memory.

2. The computing-device program product of claim 1 in which the data memory in the intermediary device comprises an address resolution protocol cache and in which the physical layer addresses stored in the cache are media access control addresses.

3. The computing-device program product of claim 1 in which the intermediary device is an access point.

4. The computing-device program product of claim 3 in which the local area network comprises devices which are reachable only by using the access point.

5. The computing-device program product of claim 1 in which the intermediary device is a DHCP server.

6. A computing-device implemented method for handling address resolution protocol requests, the method being implemented on an intermediary device in a local area network, the intermediary device comprising data memory for mapping Internet protocol addresses to physical layer addresses for devices in the local area network, the method comprising the following steps:

(a) receiving a multicast address resolution protocol request having an Internet protocol address for a device on the local area network,

(b) extracting the Internet protocol address contained in the multicast address resolution protocol request,

(c) accessing the data memory in the intermediary device to obtain a physical layer address mapped to the extracted Internet protocol address if the Internet protocol address is present in the data memory, and

(d) forwarding a directed address resolution protocol request to the local area network device corresponding to the physical layer address obtained from the intermediary device data memory.

7. The method of claim 6 in which the data memory in the intermediary device comprises an address resolution protocol cache and in which the physical layer addresses stored in the cache are media access control addresses, the step of accessing the data memory in the intermediary device comprising the step of accessing the address resolution protocol cache to obtain the media access control address mapped to the extracted Internet protocol address.

8. The method of claim 6 in which the steps implemented on the intermediary device are implemented on an access point.

9. The method of claim 8 in which the local area network comprises devices which are reachable only by using the access point.

10. The method of claim 6 in which the steps implemented on the intermediary device are implemented on a DHCP server.