1. A method for preserving stable calls during failover, comprising:
during a dialog between two user endpoints, determining whether a standby call processor has become operational, the standby call processor becoming operational when a corresponding primary call processor is in fault;
receiving a signaling protocol message from a requester after the standby call processor becomes operational;
determining whether the signaling protocol message includes an in-dialog signaling protocol request;
responsive to determining that the signaling protocol message includes the in-dialog signaling protocol request, determining whether a call state associated with the dialog is found in memory; and
responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request without terminating the dialog.
2. The method of claim 1, further comprising responsive to determining that the standby call processor has become operational, initiating a failover transition timer; and
wherein responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request, comprises:
responsive to determining that the call state associated with the dialog is not found in memory, determining whether the failover transition timer has expired; and
responsive to determining that the failover transition timer has expired, returning the non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request.
3. The method of claim 2, further comprising responsive to determining that the failover transition timer has not expired, returning a call terminating error response in response to the in-dialog signaling protocol request, the call terminating error response causing the requester to terminate the dialog.
4. The method of claim 3, wherein the call terminating error response comprises a session initiation protocol \u201c481 Calltransaction does not exist\u201d error response.
5. The method of claim 2, wherein the non-call terminating error response comprises a header specifying a value of the failover transition timer.
6. The method of claim 1, wherein the signaling protocol message comprises a session initiation protocol message and the in-dialog signaling protocol request comprises an in-dialog session initiation protocol request; and the method further comprising responsive to determining that the session initiation protocol message does not include the in-dialog session initiation protocol request, processing the session initiation protocol request according to session initiation protocol standards.
7. The method of claim 1, wherein the signaling protocol message comprises a session initiation protocol message; and the method further comprising responsive to determining that the call state associated with the dialog is found in memory, processing the session initiation protocol request according to session initiation protocol standards.
8. A system for preserving stable calls during failover, comprising:
a memory for storing a program for preserving stable calls during failover; and
a processor responsive to computer-executable instructions contained in the program that, when executed by the processor, cause the processor to perform operations comprising:
during a dialog between two user endpoints, determining whether a standby call processor has become operational, the standby call processor becoming operational when a corresponding primary call processor is in fault,
receiving a signaling protocol message from a requester after the standby call processor becomes operational,
determining whether the signaling protocol message includes an in-dialog signaling protocol request,
responsive to determining that the signaling protocol message includes the in-dialog signaling protocol request, determining whether a call state associated with the dialog is found in memory, and
responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request without terminating the dialog.
9. The system of claim 8, the processor responsive to further computer-executable instructions contained in the program that, when executed by the processor, cause the processor to perform operations comprising responsive to determining that the standby call processor has become operational, initiating a failover transition timer; and
wherein responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request, comprises:
responsive to determining that the call state associated with the dialog is not found in memory, determining whether the failover transition timer has expired, and
responsive to determining that the failover transition timer has expired, returning the non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request.
10. The system of claim 9, the processor responsive to further computer-executable instructions contained in the program that, when executed by the processor, cause the processor to perform operations comprising responsive to determining that the failover transition timer has not expired, returning a call terminating error response in response to the in-dialog signaling protocol request, the call terminating error response causing the requester to terminate the dialog.
11. The system of claim 9, wherein the non-call terminating error response comprises a header specifying a value of the failover transition timer.
12. The system of claim 8, wherein the signaling protocol message comprises a session initiation protocol message and the in-dialog signaling protocol request comprises an in-dialog session initiation protocol request; and the processor responsive to further computer-executable instructions contained in the program that, when executed by the processor, cause the processor to perform operations comprising responsive to determining that the session initiation protocol message does not include the in-dialog session initiation protocol request, processing the session initiation protocol request according to session initiation protocol standards.
13. The system of claim 8, wherein the signaling protocol message comprises a session initiation protocol message; and the processor responsive to further computer-executable instructions contained in the program that, when executed by the processor, cause the processor to perform operations comprising responsive to determining that the call state associated with the dialog is found in memory, processing the session initiation protocol request according to session initiation protocol standards.
14. A non-transitory computer-readable medium having instructions stored thereon that, when executed by a processor, cause the processor to perform operations comprising:
during a dialog between two user endpoints, determining whether a standby call processor has become operational, the standby call processor becoming operational when a corresponding primary call processor is in fault;
receiving a signaling protocol message from a requester after the standby call processor becomes operational;
determining whether the signaling protocol message includes an in-dialog signaling protocol request;
responsive to determining that the signaling protocol message includes the in-dialog signaling protocol request, determining whether a call state associated with the dialog is found in memory; and
responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request without terminating the dialog.
15. The non-transitory computer-readable medium of claim 14, the operations further comprising responsive to determining that the standby call processor has become operational, initiating a failover transition timer; and
wherein responsive to determining that the call state associated with the dialog is not found in memory, returning a non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request, comprises:
responsive to determining that the call state associated with the dialog is not found in memory, determining whether the failover transition timer has expired; and
responsive to determining that the failover transition timer has expired, returning the non-call terminating error response in response to the in-dialog signaling protocol request, the non-call terminating error response causing the requester to terminate the in-dialog signaling protocol request.
16. The non-transitory computer-readable medium of claim 15, the operations further comprising responsive to determining that the failover transition timer has not expired, returning a call terminating error response in response to the in-dialog signaling protocol request, the call terminating error response causing the requester to terminate the dialog.
17. The non-transitory computer-readable medium of claim 16, wherein the call terminating error response comprises a session initiation protocol \u201c481 Calltransaction does not exist\u201d error response.
18. The non-transitory computer-readable medium of claim 15, wherein the non-call terminating error response comprises a header specifying a value of the failover transition timer.
19. The non-transitory computer-readable medium of claim 14, wherein the signaling protocol message comprises a session initiation protocol message and the in-dialog signaling protocol request comprises an in-dialog session initiation protocol request; and the operations further comprising responsive to determining that the session initiation protocol message does not include the in-dialog session initiation protocol request, processing the session initiation protocol request according to session initiation protocol standards.
20. The non-transitory computer-readable medium of claim 14, wherein the signaling protocol message comprises session initiation protocol message; and the operations further comprising responsive to determining that the call state associated with the dialog is found in memory, processing the session initiation protocol request according to session initiation protocol standards.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of attaching metal members for forming an automotive vehicle structure, comprising the steps of:
(a) providing a first metal member;
(b) contacting the first metal member with a second metal member;
(c) providing a metal fastener that is substantially symmetrical about a central axis, the metal fastener including a radially enlarged cap portion and a shank portion extending from the cap portion, the fastener also including a core with a cladding covering at least a portion of an outer peripheral surface of the core wherein the cladding is metallurgically bonded with the core;
(d) rotating the metal fastener about the axis using a rotary driving apparatus; and
(e) driving the metal fastener through the first member and into the second member during rotation of the fastener thereby inducing friction between the fastener, the first member and the second member for at least locally melting portions of the cladding, the first member and the second member to form a flowable material about the fastener wherein;
i) the fastener is driven only partially into the second member; and
ii) the melted portions of the cladding alloy with the melted portions of the first and second members to metallurgically bond the first and second metal members to the fastener; and
(f) solidifying the flowable material for integrally attaching the flowable material to the first member and second member with a metallurgical bond.
2. A method as in claim 1 wherein the core of the fastener is formed of a material with a higher melting point than the first member and the second member.
3. A method as in claim 1 wherein the fastener includes a groove and the flowable material flows into the groove.
4. A method as in claim 1 wherein the fastener includes indentations for increasing friction between the fastener and the first member.
5. A method as in claim 1 wherein the first member is an aluminum-based sheet metal and the second member is an aluminum metal casting.
6. A method as in claim 1 wherein the core of the fastener is formed of high carbon steel and the cladding is formed of a zinciron alloy.
7. A method as in claim 1 wherein the core of the fastener is formed of high carbon steel and the cladding is formed of a aluminumiron alloy.
8. A method as in claim 1 wherein the core of the fastener is formed of a titanium alloy and the cladding is formed of a titaniumsilicon alloy.
9. A method of attaching a metal sheet to a metal substrate for forming an automotive vehicle structure, comprising the steps of:
(a) placing the metal sheet on the metal substrate such that a first surface of the sheet interfaces with a surface of the metal substrate, wherein the metal sheet and the metal substrate are adapted for incorporation into an automotive vehicle;
(b) providing a metal fastener having a core with an outer peripheral surface and a cladding disposed upon and metallurgically bonded with the peripheral surface wherein;
i) the cladding is formed of a material capable of metallurgically bonding with the sheet and the substrate;
ii) the core is formed of a material of a substantially higher melting point than the sheet and substrate; and
iii) the fastener is substantially symmetrical about a central axis and includes a non-circular cavity formed therein;
(c) rotating the metal fastener about the axis using a rotating apparatus having a member that can be temporarily matingly fit within the non-circular cavity of the fastener;
(d) driving the metal fastener through the metal sheet and into the metal substrate during rotation of the fastener thereby inducing friction between the fastener, the sheet and the substrate for at least locally melting portions of the cladding, the sheet and the substrate to form a flowable material about the core of the fastener wherein the fastener is driven through the sheet and is only partially driven through the substrate; and
(e) allowing the flowable material to solidify for integrally attaching the flowable material, the fastener, the sheet and the substrate together wherein the cladding metallurgically bonds with the sheet and substrate.
10. A method as in claim 9 wherein the fastener further includes a leading surface for initially contacting an exposed surface of the sheet.
11. A method as in claim 9 wherein the fastener includes a groove is and the flowable material flow into the groove.
12. A method as in claim 9 wherein the fastener includes indentations for increasing friction between the fastener and the sheet.
13. A method as in claim 9 wherein the sheet is aluminum sheet metal and substrate is an aluminum metal casting.
14. A method as in claim 9 wherein the core of the fastener is formed of high carbon steel and the cladding is formed of a zinciron alloy.
15. A method as in claim 9 wherein the core of the fastener is formed of high carbon steel and the cladding is formed of a zinciron alloy.
16. A method as in claim 9 wherein the core of the fastener is formed of a titanium alloy and the cladding is formed of a titaniumsilicon alloy.
17. A method of attaching an metal sheet to a metal substrate for forming an automotive vehicle structure, comprising the steps of:
(a) placing the metal sheet on the metal substrate such that a first surface of the sheet interfaces with a surface of the metal substrate, wherein the metal sheet and the metal substrate each include the metal aluminum and are adapted for incorporation into an automotive vehicle;
(b) providing a metal fastener having a core with an outer peripheral surface and a cladding disposed upon and metallurgically bonded with the peripheral surface wherein;
i) the cladding is formed of a material that includes zinc and is capable of metallurgically bonding with the sheet and the substrate;
ii) the core is formed of steel and has a substantially higher melting point than the sheet and substrate; and
iii) the fastener is substantially symmetrical about a central axis, the fastener includes a non-circular cavity formed therein and the fastener includes a substantially cylindrical shank portion with a driving surface;
(c) rotating the metal fastener about the axis using a rotating apparatus having a member that can be temporarily matingly fit within the non-circular cavity of the fastener;
(d) contacting the driving surface of the shank portion of the fastener with a second surface of the sheet;
(e) driving the metal fastener through the metal sheet and into the metal substrate during rotation of the fastener thereby inducing friction between the fastener, the sheet and the substrate for at least locally melting portions of the cladding, the sheet and the substrate to form a flowable material about the core of the fastener wherein the fastener is driven through the sheet and is only partially driven through the substrate; and
(f) allowing the flowable material to solidify for integrally attaching the is flowable material, the fastener, the sheet and the substrate together wherein the cladding metallurgically bonds with the sheet and substrate.