# US 9,438,555 B2 · Communicating with a distribution system via an uplink access point > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,555 B2 - Document ID: US9438555B2 - Status: Granted - Kind: B2 - Application number: 14/069,105 - Filed: 2013-10-31 - Published: 2015-04-30 - Granted: 2016-09-06 - Earliest claimed: 2013-10-31 - Assignees: Aruba Networks, Inc. - Applicants: Aruba Networks, Inc. - Inventors: Gopalakrishna Raman; Santashil PalChaudhuri - Web page: https://patentgrep.com/patent/US9438555B2 ## CPC - H04L 61/103: across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP] - H04L 61/5014: using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP] - H04L 61/58: Caching of addresses or names - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present disclosure discloses a system and method for communicating with a distribution system via an uplink access point. The system includes a processor and a memory storing instructions that, when executed, cause the system to: receive, at a first network device, an original packet from a client device; identify a source MAC address of the original packet as a MAC address of the client device; identify an IP address of the original packet as an IP address of the client device; generate a modified packet from the original packet by changing the source MAC address from the MAC address of the client device to a MAC address of the first network device; preserve the IP address in the modified packet to be the IP address of the client device; and forward the modified packet from the first network device to a second network device. ## Claims ### Claim 1 A system comprising: a processor; and a memory storing instructions that, when executed, cause the system to: receive, at a first network device, an original DHCP discover message from a client device; identify a first transaction ID in the original DHCP discover message; generate a second transaction ID; generate a modified DHCP discover message from the original DHCP discover message by: replacing the first transaction ID in the original DHCP discover message with the second transaction ID; and setting a broadcast bit of the modified DHCP discover message to a broadcast state; and forward the modified DHCP discover message from the first network device to a second network device. ### Claim 2 (depends on 1) The system of claim 1, wherein the first and second network devices are access points, and the second network device is connected to a distribution system via a wired Ethernet connection. ### Claim 3 (depends on 1) The system of claim 1, wherein the instructions when executed cause the system to also: create a DHCP state entry for the client device, wherein the DHCP state entry includes an originator-XID field for storing the first transaction ID, a generated-XID field for storing the second transaction ID and a field for storing a broadcast bit of the original DHCP discover message. ### Claim 4 (depends on 1) The system of claim 1, wherein the instructions when executed cause the system to also: receive, at the first client device, an original DHCP offer message from the second network device; identify that a transaction ID of the original DHCP offer message is the second transaction ID; identify that a client ID in the original DHCP offer message is a MAC address of the client device; generate a modified DHCP offer message from the original DHCP offer message by replacing the transaction ID of the original DHCP offer message with the first transaction ID; and forward the modified DHCP offer message to the client device according to a broadcast bit of the original DHCP discover message. ### Claim 5 (depends on 4) The system of claim 4, wherein the instructions when executed cause the system to also: receive, at the first network device, an original DHCP request message from the client device, the original DHCP request message including the first transaction ID; generate a modified DHCP request message from the original DHCP request message by: replacing the first transaction ID in the original DHCP request message with the second transaction ID; and setting a broadcast bit of the modified DHCP request message to the broadcast state; and forward the modified DHCP request message from the first network device to a second network device. ### Claim 6 (depends on 5) The system of claim 5, wherein the instructions when executed cause the system to also: receive, at the first client device, an original DHCP acknowledgement message from the second network device; identify that a transaction ID of the original DHCP acknowledgement message is the second transaction ID; identify that a client ID in the original DHCP acknowledge message is the MAC address of the client device; generate a modified DHCP acknowledgement message from the original DHCP acknowledgement message by replacing the transaction ID of the original DHCP acknowledgement message with the first transaction ID; and forward the modified DHCP acknowledgement message to the client device according to a broadcast bit of the original DHCP request message. ### Claim 7 (depends on 6) The system of claim 6, wherein the instructions when executed cause the system to also: receive an ARP request from the second network device; determine that the ARP request includes an IP address of the client device; and generate an ARP response that maps the IP address of the client device to a MAC address of the first network device. ### Claim 8 (depends on 1) The system of claim 1, wherein the instructions when executed cause the system to also: detect a removal of the client device from the first network device; and deactivate service for the client device from the first network device. ### Claim 9 A non-transitory computer-readable storage medium storing embedded instructions for a plurality of operations that are executed by one or more mechanisms implemented within one or more network devices, the plurality of operations comprising: receiving, at a first network device, an original DHCP discover message from a client device; identifying a first transaction ID in the original DHCP discover message; generating a second transaction ID; generating a modified DHCP discover message from the original DHCP discover message by: replacing the first transaction ID in the original DHCP discover message with the second transaction ID; and setting a broadcast bit of the modified DHCP discover message to a broadcast state; and forwarding the modified DHCP discover message from the first network device to a second network device. ### Claim 10 (depends on 9) The computer-readable storage medium of claim 9, wherein the first and second network devices are access points, and the second network device is connected to a distribution system via a wired Ethernet connection. ### Claim 11 (depends on 9) The computer-readable storage medium of claim 9, wherein the plurality of operations further comprises: creating a DHCP state entry for the client device, wherein the DHCP state entry includes an originator-XID field for storing the first transaction ID, a generated-XID field for storing the second transaction ID and a field for storing a broadcast bit of the original DHCP discover message. ### Claim 12 (depends on 9) The computer-readable storage medium of claim 9, wherein the plurality of operations further comprises: receiving, at the first client device, an original DHCP offer message from the second network device; identifying that a transaction ID of the original DHCP offer message is the second transaction ID; identifying that a client ID in the original DHCP offer message is a MAC address of the client device; generating a modified DHCP offer message from the original DHCP offer message by replacing the transaction ID of the original DHCP offer message with the first transaction ID; and forwarding the modified DHCP offer message to the client device according to a broadcast bit of the original DHCP discover message. ### Claim 13 (depends on 12) The computer-readable storage medium of claim 12, wherein the plurality of operations further comprises: receiving, at the first network device, an original DHCP request message from the client device, the original DHCP request message including the first transaction ID; generating a modified DHCP request message from the original DHCP request message by: replacing the first transaction ID in the original DHCP request message with the second transaction ID; and setting a broadcast bit of the modified DHCP request message to the broadcast state; and forwarding the modified DHCP request message from the first network device to a second network device. ### Claim 14 (depends on 13) The computer-readable storage medium of claim 13, wherein the plurality of operations further comprises: receiving, at the first client device, an original DHCP acknowledgement message from the second network device; identifying that a transaction ID of the original DHCP acknowledgement message is the second transaction ID; identifying that a client ID in the original DHCP acknowledge message is the MAC address of the client device; generating a modified DHCP acknowledgement message from the original DHCP acknowledgement message by replacing the transaction ID of the original DHCP acknowledgement message with the first transaction ID; and forwarding the modified DHCP acknowledgement message to the client device according to a broadcast bit of the original DHCP request message. ### Claim 15 (depends on 14) The computer-readable storage medium of claim 14, wherein the plurality of operations further comprises: receiving an ARP request from the second network device; determining that the ARP request includes an IP address of the client device; and generating an ARP response that maps the IP address of the client device to a MAC address of the first network device.