# US 8,571,198 B2 · Handling redirect calls > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,571,198 B2 - Document ID: US8571198B2 - Status: Granted - Kind: B2 - Application number: 11/545,744 - Filed: 2006-10-10 - Published: 2008-04-10 - Granted: 2013-10-29 - Earliest claimed: 2006-10-10 - Assignees: Cisco Technology, Inc. - Applicants: Parameswaran Kumarasamy; Sandeep Singh Kohli; Kavithadevi Parameswaran; Vinay Pande - Inventors: Parameswaran Kumarasamy; Sandeep Singh Kohli; Kavithadevi Parameswaran; Vinay Pande - Web page: https://patentgrep.com/patent/US8571198B2 ## CPC - H04M 3/54: Arrangements for diverting calls for one subscriber to another predetermined subscriber {(based on the calling party profile H04M3/42059; based on location H04M3/42348; based on presence H04M3/42365; to voice mail H04M3/53308)} - H04L 65/1069: Session establishment or de-establishment - H04M 3/53: Centralised arrangements for recording incoming messages {, i.e. mailbox systems} - H04M 7/006: {Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer (H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42)} - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract In a particular embodiment, a network device receives, from a first device, a first call request for a second device. The network device may then send the first call request to a redirect server, which can determine where to send the call. The network device receives a response from the redirect server indicating an address to redirect the call request to. The network device then determines a redirect ID for the redirect. The network device sends a message to the first device with the redirect ID where the message indicates that a redirection occurred to the third device. The network device then receives a second call request from the first device that includes the redirect ID. The network device determines if the call was part of a previous redirect. If so, the second call request is sent to the address associated with the redirect ID. ## Claims ### Claim 1 A method comprising: receiving, from a first device at a network device, a first call request directed to a second device; sending the first call request from the network device to a redirect server; receiving a redirection response at the network device from the redirect server indicating a redirection of a destination of the first call request from the second device to a third device, the redirection response comprising a third device address for the third device; based on receiving the redirection response from the redirect server, generating, using the network device, a redirection information for the first call, the redirection information being associated with the third device address and including a redirection identifier; storing, using the network device, the redirection information; sending a message from the network device to the first device, the message indicating a redirection of the first call request to the third device and comprising a respond-to address for the network device, the message also including the redirection identifier; receiving a second call request from the first device at the network device, the second call request being addressed to the respond-to address for the network device and including the redirection identifier; identifying, using the network device, the stored redirection information based on the redirection identifier included in the second call request; determining, using the network device and based on the identified redirection information, that the second call request is a redirection based on the first call request; and based on the determining, sending, using the network device, the second call request to the third device using the third device address that is obtained using the redirection information. ### Claim 2 (depends on 1) The method of claim 1, further comprising deleting the stored redirection information after receiving the second call request such that subsequent call requests directed to the second device are not sent to the third device without being sent to the redirect server. ### Claim 3 (depends on 1) The method of claim 1, further comprising determining the redirection information based on the first call request. ### Claim 4 (depends on 1) The method of claim 1, wherein the redirection information is associated with the first call request such that a call request directed to the second device that is different from the first call request cannot use the redirected information associated with the first call request. ### Claim 5 (depends on 1) The method of claim 1, wherein the redirection response is a SIP 302 message. ### Claim 6 (depends on 1) The method of claim 1, wherein the third device address for the third device is not included in the message sent to the first device. ### Claim 7 (depends on 1) The method of claim 1, wherein the network device is configured to send the second call request to the redirection server provided the second call request is not for the redirection based on the first call request. ### Claim 8 An apparatus comprising: one or more processors; and logic encoded in one or more non-transitory tangible media for execution by the one or more processors and when executed operable to: receive, from a first device at a network device, a first call request directed to a second device; send the first call request from the network device to a redirect server; receive a redirection response at the network device from the redirect server indicating a redirection of a destination of the first call request from the second device to a third device, the redirection response comprising a third device address for the third device; based on receiving the redirection response from the redirect server, generate, using the network device, a redirection information for the first call, the redirection information being associated with the third device address and including a redirection identifier; store, using the network device, the redirection information; send a message from the network device to the first device, the message indicating a redirection of the first call request to the third device and comprising a respond-to address for the network device, the message also including the redirection identifier; receive a second call request from the first device at the network device, the second call request being addressed to the respond-to address for the network device and including the redirection identifier; identify, using the network device, the stored redirection information based on the redirection identifier included in the second call request; determine, using the network device and based on the identified redirection information, that the second call request is a redirection based on the first call request; and based on determining that the second call request is a redirection based on the first call request, send, using the network device, the second call request to the third device using the third device address that is obtained using the redirection information. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the logic when executed is further operable to delete the stored redirection information after receiving the second call request such that subsequent call requests directed to the second device are not sent to the third device without being sent to the redirect server. ### Claim 10 (depends on 8) The apparatus of claim 8, wherein the logic when executed is further operable to determine the redirection information at run-time. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein the redirection information is associated with the first call request such that a call request directed to the second device that is different from the first call request cannot use the redirection information associated with the first call request. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein the redirection response is a SIP 302 message. ### Claim 13 (depends on 8) The apparatus of claim 8, wherein the third device address for the third device is not included in the message sent to the first device. ### Claim 14 (depends on 8) The apparatus of claim 8, wherein the network device is configured to send the second call request to the redirection server provided the second call request is not for the redirection based on the first call request. ### Claim 15 An apparatus comprising: means for receiving, from a first device at a network device, a first call request directed to a second device; and instructions encoded in a non-transitory machine-readable medium for execution by a processor, the instructions when executed by the processor cause the processor to perform operations including: sending the first call request from the network device to a redirect server; receiving a redirection response at the network device from the redirect server indicating a redirection of a destination of the first call request from the second device to a third device, the redirection response comprising a third device address for the third device; based on receiving the redirection response from the redirect server, generating, using the network device, a redirection information for the first call, the redirection information being associated with the third device address and including a redirection identifier; storing, using the network device, the redirection information; sending a message from the network device to the first device, the message indicating a redirection of the first call request to the third device and comprising a respond-to address for the network device, the message also including the redirection identifier; receiving a second call request from the first device at the network device, the second call request being addressed to the respond-to address for the network device and including the redirection identifier; identifying, using the network device, the stored redirection information based on the redirection identifier included in the second call request; determining, using the network device and based on the identified redirection information, that the second call request is a redirection based on the first call request; and based on the determining, sending, using the network device, the second call request to the third device using the third device address that is obtained using the redirection information. ### Claim 16 (depends on 1) The method of claim 1, further comprising storing address information for the second and third devices in the network device. ### Claim 17 (depends on 1) The method of claim 1, further comprising storing, in the network device, address information for at least the third device at least between a first time of receiving a redirection response at the network device transmitted from the redirect server and either of (1) a second time of sending the second call request directly from the network device to the third device or (2) an expiration of a timeout condition. ### Claim 18 (depends on 17) The method of claim 17, further comprising: storing, in the network device, the address information for at least the third device upon an occurrence of receiving the redirection response; and including the redirection identifier in the message to the first device, wherein the redirection identifier is different from the third device address.