Using PSTN Reachability to Verify Caller ID Information in Received VoIP Calls

• US 20090022155A1
• Filed: 07/20/2007
• Published: 01/22/2009
• Est. Priority Date: 07/20/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Wing, Daniel G., Rosenberg, Jonathan, Jennings, Cullen F.
• Granted Patent: US 8,204,047 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 65/1053 IP private branch exchange [PBX] functionality entities or arrangements circuit switched PBXs H04M3/00

Abstract

A system for verifying caller ID information in received VoIP calls. In particular implementations, a method includes receiving a caller identification (ID) identifying a calling party telephone number in a call initiation message transmitted from a VoIP call agent; determining the identity of the VoIP call agent; verifying that a public switched telephone network (PSTN) call to the calling party telephone number would arrive at a VoIP call agent having the determined identity; and applying, responsive to the call initiation message, one or more rules based at least in part on the verifying step.

Claims

1. A method comprising:

receiving a caller identification (ID) identifying a calling party telephone number in a call initiation message transmitted from a VoIP call agent;

determining the identity of the VoIP call agent;

verifying that a public switched telephone network (PSTN) call to the calling party telephone number would arrive at a VoIP call agent having the determined identity; and

applying, responsive to the call initiation message, one or more rules based at least in part on the verifying step.

2. The method of claim 1 wherein the verifying further comprises:

querying a registry that maps telephone numbers to the identity of the VoIP call agent; and

matching a returned identity from the query to the identity of the call agent making the call.

3. The method of claim 2 wherein the identity is an IP address.

4. The method of claim 2 wherein the identity is associated with a public key, and wherein the identity of the call agent making the call is determined through verification of key ownership.

5. The method of claim 2 further comprising verifying the call agent that sent the call based on knowledge of one or more attributes of a PSTN call made previously by the call agent to the calling party telephone number.

6. The method of claim 5 wherein the verifying comprises:

recording one or more attributes of one or more of previous PSTN calls;

transmitting a query for proof of awareness of one or more of the PSTN call attributes for a destination telephone number to a VoIP call agent; and

receiving a response to the query from the VoIP call agent.

7. The method of claim 6 wherein the PSTN call attributes comprise one or more of a start call time, an end call time, a caller identification, a call length, and a call signature.

8. The method of claim 6 wherein the PSTN call attributes comprise a call signature, wherein the call signature is based on one or more of frequency spectrum analysis, silence detection, and a password.

9. The method of claim 5 wherein the verifying further comprises

accessing a cache of Voice over Internet Protocol (VoIP) call routing information, wherein the cache comprises a plurality of validated entries, and wherein each entry comprises a telephone number or prefix and a network address of a corresponding VoIP call agent;

searching the cache for a matching entry; and

if a matching entry is found in the cache, applying one or more policies for VoIP call agents validated against the cache.

10. The method of claim 9 further wherein the verifying further comprises

accessing a registry of VoIP call routing information, wherein the registry comprises a plurality of entries, and wherein each entry comprises a telephone number or prefix and a network address of a corresponding VoIP call agent;

searching the registry for a entry;

if a matching entry is found in the registry, applying one or more policies for VoIP call agents validated against the registry; and

if no matching entry is found in either the cache or the registry, applying one or more policies for unvalidated VoIP call agents.

11. Logic encoded in one or more tangible media for execution and when executed operable to:

receive a caller identification (ID) identifying a calling party telephone number in a call initiation message transmitted from a VoIP call agent;

determine the identity of the VoIP call agent;

verify that a public switched telephone network (PSTN) call to the calling party telephone number would arrive at a VoIP call agent having the determined identity; and

apply, responsive to the call initiation message, one or more rules based at least in part on the verifying step.

12. The logic of claim 11 wherein the logic is further operable to:

query a registry that maps telephone numbers to the identity of the VoIP call agent; and

match a returned identity from the query to the identity of the call agent making the call.

13. The logic of claim 12 wherein the identity is an IP address.

14. The logic of claim 12 wherein the identity is associated with a public key, and wherein the identity of the call agent making the call is determined through verification of key ownership.

15. The logic of claim 12 wherein the logic is further operable to:

verify the call agent that sent the call based on knowledge of one or more attributes of a PSTN call made previously by the call agent to the calling party telephone number.

16. The logic of claim 15 wherein the logic is further operable to:

record one or more attributes of one or more of previous PSTN calls;

transmit a query for proof of awareness of one or more of the PSTN call attributes for a destination telephone number to a VoIP call agent; and

receive a response to the query from the VoIP call agent.

17. The logic of claim 16, wherein the PSTN call attributes comprise one or more of a start call time, an end call time, a caller identification, a call length, and a call signature.

18. The logic of claim 16, wherein the PSTN call attributes comprise a call signature, wherein the call signature is based on one or more of frequency spectrum analysis, silence detection, and a password.

19. The logic of claim 15 wherein the logic is further operable to:

access a cache of Voice over Internet Protocol (VoIP) call routing information, wherein the cache comprises a plurality of validated entries, and wherein each entry comprises a telephone number or prefix and a network address of a corresponding VoIP call agent;

search the cache for a matching entry; and

if a matching entry is found in the cache, apply one or more policies for VoIP call agents validated against the cache.

20. The logic of claim 19 further wherein the logic is further operable to:

access a registry of VoIP call routing information, wherein the registry comprises a plurality of entries, and wherein each entry comprises a telephone number or prefix and a network address of a corresponding VoIP call agent;

search the registry for an entry;

if a matching entry is found in the registry, apply one or more policies for VoIP call agents validated against the registry; and

if no matching entry is found in either the cache or the registry, apply one or more policies for unvalidated VoIP call agents.

21. An apparatus comprising:

one or more network interfaces;

a memory;

one or more processors; and

a call agent application physically stored in the memory comprising computer-readable instructions operative to cause the one or more processors to;

receive a caller identification (ID) identifying a calling party telephone number in a call initiation message transmitted from a VoIP call agent;

determine the identity of the VoIP call agent;

verify that a public switched telephone network. (PSTN) call to the calling party telephone number would arrive at a VoIP call agent having the determined identity; and

apply, responsive to the call initiation message, one or more rules based at least in part on the verifying step.